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Talking Electronics has produced two books on Model Railway Electronics.
They are Electronics for
Model Railways-1 (pdf) and Electronics for Model Railways-2
(pdf)
These books have completely sold out so we have provided them in .doc
format (Word) and .pdf
All the kits from the two books are still available and we get lots of orders,
but you must make sure
you are good at soldering and see what the module does, before ordering.
Some of the modules are available fully assembled and tested and some
have been improved or simplified
and you need to contact us before ordering anything.
email Colin Mitchell:
talking@tpg.com.au
Electronics for
Model Railways-1 .pdf
(35MB) free to download
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Model Railways-1 .doc
(13MB) free to download
Electronics for Model Railways-2 .pdf (56MB)
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For a list of every electronic symbol, see:
Circuit Symbols.
For more articles and projects for the hobbyist: see TALKING ELECTRONICS WEBSITE
email Colin Mitchell:
talking@tpg.com.au
More than 24 CIRCUITS as of 20-5-2022
Talking Electronics website has the remaining 50 projects as
kits
and the instructions are available in the two books shown above. As well as more projects
on the website.
INTRODUCTION This e-book presents a lot of interesting projects for Model Railways. Talking Electronics has produced two books for Model Railway enthusiasts (book-2 is now out of print). The two books are: Electronics for Model Railways-1 Electronics for Model Railways-2 Since releasing these two books, we have designed lots of extra projects and more are being released all the time. There is a very large group of Model Railway enthusiasts around the world and nearly everyone's layout includes more and more electronic devices, modules and controllers. But a lot of enthusiasts are not electronically adept and have either not studied electronics or had the good-fortune to have built electronic projects. That's why many of the projects we have designed recently are available as a kit or already built and tested. Even to put a kit together you have to be able to identify each part and fit it correctly as well as owning a fine tipped soldering iron and knowing how to solder quickly and cleanly to prevent overheating the component. Most Model Railway magazines don't have circuits and projects you can build, mainly because they don't have the back-up of component suppliers, reliable kit suppliers or the staff needed to answer questions on fixing kits that don't work. We have all these features at TALKING ELECTRONICS and everything is backed by emails and service. Most emails from us are very short as we have hundreds of emails to attend to each week but you must reply with one question at a time and eventually your problem will be solved. Colin Mitchell If you have DCC
Digital Command Control on your model railway, or are thinking about
using it or starting a layout with this feature, here is a website
dedicated to helping you:
Digital Command Control is a standard for a system to operate model railways
so that two or more locomotives can be controlled independently on the same
section of track. |
NOTE: Many of the projects and circuit and ideas in this eBook are available from Talking Electronics as complete kits, fully assembled, or as components at very low prices. Talking Electronics has sold over 300,000 kits during the past 45 years and about 100,000 have been Model Railway kits. You can now get many of the kits fully assembled and tested for those who have a layout but not a soldiering iron. Many of the projects are so new and different and complex that you will not understand them fully. Email: Colin Mitchell and ask for assistance before buying or doing anything. Here are some wonderful layouts and videos taken from the front and back of the trains on the layouts . . . . from MODEL RAILWAY LAYOUTS PLANS.com http://modelrailwaylayoutsplans.com/dave-tidies-up-his-layout/?inf_contact_key=93a9574ff8f6930e95fe40eaba006a971b0a3f0fd3ee5d9b43fb34c6613498d7" Video: https://youtu.be/MnBfqBCWNp4 You must join: MODEL RAILWAY LAYOUTS PLANS.com because they send a new layout every day with videos. This link show the enormous amount of wiring required for a layout with points and signals. This is the latest: http://modelrailwaylayoutsplans.com/john-shows-us-more-of-his-stunning-layout/?inf_contact_key=d02020000d3e42e28f99cc8a315cea07d18a532c4142cb79caf2b269de1401fa
Here are 2 of the latest images: There are 200 more photos of layouts on the
website:
The next stage is to add points (turn-outs) or cross-overs: |
Every project needs POWER. Power is ENERGY (actually: Power over a
period of TIME is energy) and it comes from a
battery or a POWER SUPPLY.
Power supplies are also called wall warts, plug packs,
chargers or adaptors and must be of the type that is SAFE. In other
words, you must be able to touch the output wires and the tap in the
kitchen and not get killed. USING DC ADAPTORS IN PARALLEL
Here is a typical 18v power supply for a model railway. This is the ideal supply, but it is expensive and our aim is to show how to produce the same output voltage by using much cheaper items (Plug Packs etc.)
USING
AC ADAPTORS IN PARALLEL
USING
DC ADAPTORS IN SERIES
You can connect any TWO or THREE together and the output voltage
will be the sum of all the voltages and the current will be
determined by the lowest current of the 3 adapters. If you do not have any old Plug Packs, you can buy new ones on eBay
for a few dollars.
THE BEST ADAPTOR:
The best DC adapter for all the CDU modules is a 24v or 30v supply
made from two 12v adaptors in series of three 10v adaptors in
series.
5v, 10v, 15v
POWER SUPPLY
The $2.50 plug Pack above was purchased as 12v @ 1 amp. It was
easily opened-up via a screw and clip, to reveal the PC board shown
below.
Some of the CDU projects can be supplied with 30v to 36v DC to fully charge the electrolytic(s). You can make a 36v supply very cheaply by using 24v and 12v plug packs and these are available on eBay for less than $10.00 (for both) including postage. Simply connect the leads as shown in the following diagram to get 36v. Some of these plug packs have a current detecting overload circuit and "shut-down" if the current is more than 1 amp (even for a millisecond). To prevent this we add a 47 ohm resistor. This "trick" only applies when you are using the plug packs for our CDU modules as the high current is only required for a few seconds and then falls to a very low value and the resistor will not get warm when used for this particular application.
THE ALTERNATIVE TO A WALL WORT The latest module to have this feature is JIM's CDU MkII and it has a mini trim pot to adjust the output voltage from 13v to 27v DC to cater for all different types of solenoid points. This module has on-board push-switches to control the position of the point and each module is designed to be connected to a single point or two or three points that ALL need to be activated AT THE SAME TIME. You can see the project HERE. This is just one way to get around the problem for the moment, but at some point in your plans to produce a large layout, you will need a POWER SUPPLY. You can spend a lot of money on a POWER SUPPLY but Talking Electronics is always aiming to show the cheapest and best way to get something at the lowest cost. Let's look at what we are talking about:
BENCH POWER SUPPLY
They come in all sorts of arrangements and offer current
limiting and output voltages from 0v to 35v (or higher) at 1 amp to 10 Amp or more. Power Supply MkII
The following project is a 0v to 12v BENCH POWER SUPPLY with current
limiting and has an output of 1 amp. This is sufficient for all types of
testing and you can increase the values by referring to the circuit. This is the cheapest,
safest Power Supply you can get.
Here is a set of 4 Li-ion cells. Just use the 4 lower cells in a 4-cell carrier. The top cell is just to increase the voltage slightly so the project will produce slightly more than 12v at 1 amp.
The 4-cell carrier can be bought on eBay for about
$2.50
The charger below will charge a single cell at about 500mA to 700mA and connects to your USB port on a laptop. You can only charge one cell at a time with this arrangement.
The 1 ohm resistor will discharge the cell quickly. The cell voltage
must not go below a minimum voltage of
2.8v. You need to place a voltmeter across the resistor while
discharging to make sure you do not discharge the cell below its
recommended minimum. The module in the photo charges the
cell quite quickly and at 4.2v the cell is charged to 90% (or more)
and the circuit turns OFF. More details of the project shown above can be found HERE. It describes a 1 amp adjustable POWER SUPPLY that can be used to power your locos or as a BENCH POWER SUPPLY for all your testing.
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CURRENT A small loco takes 300mA to 600mA and you need a 1AMP supply to make sure the necessary current can be supplied as the motor will take 800mA to 900mA when starting and accelerating and when hauling a number of coaches. For a DC layout, you will generally only be running one loco at a time and a 1-Amp supply will be sufficient. The current values mentioned above apply when the supply is 12v. If the supply drops to say 10v, the current will be less and if the supply increases to 14v, the current will increase by a considerable amount (when the same motor is connected). It is impossible to state the actual values because the current taken by a motor increases and decreases due to the load and this load is not only the velocity of the train, but the acceleration and inclination of the track and also the rpm of the motor (as it takes more energy to rotate at higher rpm) and lots more current when the motor is "loaded." AC TO DC Before we finish, there is a bit of theory that needs to be understood. We have mentioned the AC voltage and DC voltage on (or for) many of the projects. The two values are a little bit different and you may be wondering why. The technical reason is this: When you deliver 10v AC to a circuit that has diodes and capacitors (electrolytics) that convert the voltage to DC, the output is 40% higher than "10" because the 10v AC is actually 14v at the instant when the voltage is rising to a maximum and the capacitors get charged to this value. There is a loss of about 1.5v across the diodes in the circuit and the output becomes 12.5v Quite often the manufacturer of the 10v AC transformer will add a few extra turns and the voltage will be 13v AC (under no load). This is done because the output drops when full current is delivered (because the transformer is very poor quality) and this will ensure the output never goes below 10v AC. It drops from 13v to 10v - under full load. However the 13v AC will produce 18.2v AC minus 1.5v = 16.7v DC when unloaded and if you deliver more than 13v AC, the resulting unloaded voltage may be too high for some of the electronic components - especially IC's.
CONCLUSION ooooooooooooooooooooo0000000000000000000000000oooooooooooooooo
BOOST CONVERTER
|
This is PART "A" of our
discussion on controlling a point.
A Point Controller is a "device" or "MOTOR" or "SOLENOID" that
changes the point from "ahead" to "Siding." All layouts
need a point or lots of points so you can make
an impressive layout and have the trains leave and enter the main line
and provide shunting yards and loops and interconnecting lines.
If you have a solenoid operated point, we will cover
it later:
We connect a motor and worm gearbox as shown in the following image to the actuating lever on the point:
Image shows
the control rod on the gearbox is
The following image is the module that controls and limits the motor's operation. It allows the motor to be connected to a 9v to 16v AC or DC supply.
You get a micro motor with worm
gearbox and module and DPDT push-push switch
and the position of the point is shown on the red and green LEDs on
the module.
The movement of the point is fairly rapid. There are other modules
with slow movement.
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CHOICE NUMBER 2:
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NUMBER 3: ![]() The Printed Circuit Board has 2 x 500R mini trim pots to adjust the amount of travel of the output arm.
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CHOICE NUMBER 5:
Click Here
to order. oooooooooooooo0000000000000000000000000000oooooooooooooooo
CHOICE NUMBER 6: oooooooooooooo0000000000000000000000000000oooooooooooooooo
CHOICE NUMBER 7: The on-board tactile buttons need to be pressed for about 1/2 second for the program to recognise the button and activate the servo to set the point to the correct position. You need to set each point so that the PC board reflects the correct position of the point. Do this will all 5 points and you are ready to drive the loco. oooooooooooooo0000000000000000000000000000oooooooooooooooo
CHOICE NUMBER 8:
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CHOICE NUMBER 9: A description of how the circuits works is HERE
CHOICE NUMBER 10:
The angular movement of the
motor/gearbox is controlled by the resistors under the PCB and the voltage of
the pre-voltage module. The position of the point is shown by 2 LEDs on the module with an
outline showing the track with siding. This makes it easy to see the position of
the point. SUMMARY |
POINT MOTORS Here are 4 common POINT MOTORS. They can be connected to our CDU Modules to produce fast switching of the rails and at the same time the CDU Module prevents the solenoids getting hot or warm. ![]() ![]() |
This is PART "B" of our
discussion on controlling a point. (see PART "A" to control a point with a motor) The most common type of point motor is a solenoid that moves the rails from one position to the other. It is also called a TURN-OUT MOTOR:
It must be activated for less than 1 second. It was activated for 4 seconds and it MELTED !! The plastic core melted and bubbled through the coil and the activating rod is FROZEN. That's what this article is all about. If you add a CDU module to activate these POINT MOTORS they will not get damaged.
(the core is called an ARMATURE) The SOLENOID Point Motor consists of two
coils of wire that alternately pull a metal rod into the middle of the solenoid and
at the same time change the position of the point.
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CHOICE
NUMBER 8: -
see the new version (dual) for $18.00
The screw terminals make it easy to fit to your layout.
touches and pushes the contact. This occurs when the lever is in the "12 O'Clock" position and you must move it past this position to prevent the point motor "burning-out." ![]()
The PL-26 switch is called a PECO PASSING SWITCH
because it only makes contact when the lever is just before or just
after the top position. This means it is not making contact when
fully left or fully right. Our CDU module fits between the Power Supply and the switch or
switches to a SOLENOID POINT MOTOR. It is designed to deliver a short pulse of
energy to the solenoid to change the position of the point. A
Passing Switch will deliver a pulse of energy but if it gets stuck
in the mid-position, our CDU will prevent the point motor "burning
out."
CAPACITOR DISCHARGE UNIT MkII - MODIFICATION
Universal EU US Plug Switching Adapter AC 220V-240V To 5 V 12 V
24V Volt Power Supply DC 5V 12V 24V 1A 2A 3A 5A Power Adapter
Output Voltage 24v US Plug Current 1A $3.60 This gives you a 36v supply for less than $10.00 You just
need to wire the outputs in series.
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CHOICE
NUMBER 8A:
Comes built with toggle switches (just standard switches without rubber grips) and a front panel with 4 screws. oooooooooooooo0000000000000000000000000000oooooooooooooooo
CHOICE
NUMBER 8B: FOR 2-KATO POINTS
To operate a KATO point connect the two outer screw terminals
together
CHOICE
NUMBER 9:
The amount of energy delivered to the solenoid depends on the
voltage delivered to the module. For 12v DC supply, the solenoid
will work very delicately and will be suitable for small solenoids
used in "Z-scale." Supplying 16v AC will deliver FOUR times more
energy and will be suitable for larger scales and can operate 2
points. oooooooooooooo0000000000000000000000000000oooooooooooooooo CHOICE NUMBER 10: Talking Electronics has an In-line version that takes up
less space on your console.
This In-line CDU module has two LEDs that show the position of the point.
It is fitted to your control panel and the LEDs show the position of a point.
This very handy for a point that cannot be seen from the control area.
The input voltage needs to be 12v to 16v AC or DC and you may need two adaptors in series to get this voltage. See Chapter 1 for the Plug Packs (or Choice Number 11). oooooooooooooo0000000000000000000000000000oooooooooooooooo
CHOICE
NUMBER 11:
You can use the "accessories"
output of a train transformer if it is DC (14v DC to 24v DC) or if
the accessories output is AC (14v AC to 18v AC). The module has been
tested up to 20v AC but it is best to keep to 18v AC max.
This principle applies to all CDU's but it does limit the "inrush current" and you can email me if you are adding a VOLTAGE DIVIDER to another project to see if any reduction in operation will occur. oooooooooooooo0000000000000000000000000000oooooooooooooooo
A larger CDU is also available from
Talking Electronics, to change up to 8 points at the same time:
This Capacitor Discharge Unit is easy to
connect to your layout with screw terminals. A Switch Module can be fitted to this CDU to activate the solenoid point and also show the position of the point via two LEDs:
The SWITCH MODULE (shown in
the images above) connects to 18,000u CDU for $7.00 extra. oooooooooooooo0000000000000000000000000000ooooooooooooooooo
CHOICE
NUMBER 13:
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NUMBER 14:
The VOLTAGE REDUCER MODULE consists of a 3-terminal block and 4
power diodes and screws into the 3-terminal block on the module.
If the input voltage is 17v, you can remove one of the diodes by soldering a link across one of the diodes (to short it out), as shown in the following image:
If the input voltage is 16v you can remove 2 diodes and if it is 15v, you do not need the VOLTAGE REDUCER MODULE. If you want to deliver 15.5v DC to CDU 18,000u Slimline - MkII with two plug packs, here is the circuit:
A Switch Module can be fitted to this CDU to activate the solenoid point and also show the position of the point via two LEDs:
The SWITCH MODULE (shown in
the images above) connects to 18,000u SLIMLINE CDU for $7.00 extra.
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The name: Capacitor Discharge Unit with SPDT Switch - SLIM
has been chosen to identify it from all the other CDU modules made
by Talking Electronics.
All the components fit on the PC board and the module comes with 2 x 1,000u electrolytics. The input can be 12vAC to 15vAC or 20vDC to 35vDC. You can make a 12v 24v or 36v supply very cheaply by using 24v and
12v plug packs. These are available on eBay for less than $10.00
(combined) including postage.
Using an old Printer Power Supply
There are lots of other power supplies from discarded electronic equipment and you just have check everything before you throw it out. 2 MODULES
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CDU with output for 2-Aspect signals:
The image shows the 3-wire connection
outputs for the 2-Aspect signals. It needs the power-supply module for the CDU to work for both Siding and Main It will not work without the 4,700u power supply module
This module comes with a pre-voltage module to make things easy for
you. You just need a supply of 9v to 20v DC and the
pre-voltage module will output 25.5v to the CDU modules.
You can mount 2 or 5 modules
"side-by-side" and use the face-plate shown in the photo below to
connect them together and fit them to your console. The circuit for the 5-Modules version has 2 x 4,700u electrolytics
in the power supply section because the charging of the 2,200u (in
the second part of the circuit shown above), when the switch is in
the "MAIN" position, will take a lot of energy from the 4,700u in
the power supply and the voltage across it will dip 50%
(theoretically). When 5 modules are connected to the power supply,
this will be passed to the other modules and affect the operation of
the other points at a time when they should not be affected.
CHOICE
NUMBER 16:
CDU 4700u
Slimline
This CDU (Capacitor
Discharge Unit) module has been designed with voltage-doubling
components so you can use the 12v DC or 15v AC terminals of your
train power supply. It also has voltage regulating to prevent
over-charging the electrolytic and an indicator LED to show when the
electrolytic is fully charged.
Jim's CDU MkII
THE CIRCUIT |
SOLDERING THE KIT Soldering these kits is simple if you have a bit of experience in soldering small components because all the parts are identified on the PC Board. You will need tweezers for the surface-mount components. We supply solder THAT IS NOT CHINESE SOLDER. Do not use Chinese solder as it does not contain the correct percentage of tin and lead and it does not "run" or melt or flow properly and does not produce a shiny joint. It did not work for me and I threw it in the trash. The frustration of trying to get a shiny joint was enormous. The first things you add to the board are the 13 surface mount resistors. Add a small amount of solder to one land for each resistor and pick them up with tweezers with the numbers showing and solder one end with the solder that is already on the land. Then go around and solder the other ends by adding a small amount of solder to each resistor. Watch the solder "click" onto the resistor and it will look a little bit like a skateboard ramp. The rest of the components are through-hole and it does not matter if you start at one end of the board or with the small components first. Every component is identified on the board and most of the parts have to be fitted around the correct way - so look at the legend on the board. The LEDs must be soldered very quickly otherwise they will be damaged. The mark of a well-designed PCB is being able to put it together with a handful of parts and no other reference. And the mark of a well-designed circuit is 100% operation with every board. You cannot afford to be messing around, "adjusting" the component values and trying to work out why it does not work. That's why every value has a reason and a purpose. This can only be gained by working on hundreds of circuits and gaining the experience, knowledge and understanding. The circuits are provided with all the projects to give you this experience. And to help you fix something, if it "blows up." ![]()
Alternatively, you can ask for Track Pick-off "using Rail Joiners." You will need to get to the track, remove the rail joiners that presently connect the rails, and fit the track jointers as shown in the following image:
CONCLUSION oooooooooooo000000000000000000oooooooooooooo
CHOICE
NUMBER 18:
The original circuit used two 555 IC's. The new and
improved circuit uses a microcontroller and 15 fewer components !!
That's why some of the components are no longer required.
CHOICE
NUMBER 19:
The SLOW MOTION SWITCH MACHINE costs $8.50 usd and comes with 2
metre of 3-core lead. This is the latest Slow Motion Switch Machine using digital control
to the motor. The switch MUST be fitted so the letters "C" "NO" and "NC" can be
seen as per the image above. They will not work if fitted the wrong
way around. These are special switches - push switches - and not
toggle switches. Push the legs through the holes of the printed
circuit board and before you solder the pins, try the operation of
the module. When you know it operates correctly, solder the pins
with the fine solder provided. |
TURTLE - 2 POINTS CIRCUIT All the
work is
done by the microcontroller.
|
CHOICE
NUMBER 20: 5 Point Controller for Servos This module operates 1,2,3,4, or 5 servos very slowly.
Buy 5 Point Controller for Servos $25.00usd plus $6.50usd post |
CHOICE
NUMBER 21: 5 POINT IDENTIFICATION for Passing Switches This module shows the position of 5 points via blue and orange LEDs on a faceplate that fits on your console. If you have solenoid points that operate via PASSING SWITCHES or CENTRE-OFF TOGGLE SWITCHES or any other type of switch to activate the point for a very short period of time, this module can be connected to the 5 points and it will record the position of the point via a LATCHING RELAY. These are MEMORY RELAYS with very short activation time and hold the information, even after the power is turned off and re-applied. The main module is connected to the face-plate with 7 wires (about 100mm long) so it can be screwed to your console. The cost of the module, fully built and tested, is $25.00 USD plus $8.50 USD shipping. You can get 2 metre leads to connect the point to the 3-screw terminals on the back of the main module for $2.00 per lead. Contact Colin Mitchell at Talking Electronics before buying any items. email Colin Mitchell: talking@tpg.com.au Buy 5 Point Identification for Passing Switches $25.00usd plus $8.50usd post
|
The image on the left is just an example
to show the connection of the servo to the point. The servo
can lay down to take up less room.
There are many ways to
connect the servo to the "switching lever" and here's one
way that adjusts the movement of the arm on the servo to the
travel needed by the switching lever. The following images clearly
show how the 3.7g SERVO is connected to the point via a
LINKAGE:
THE SUPPLY
FITTING the REED
SWITCHES
PARTS LIST
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Automatic Point Switcher
Automatic Point Switcher is
available from: This is another Automatic Point
Controller from Talking Electronics to cover slightly
different requirements.
4
Points CDU Controller
This
module will change the position of 4
point motors via the 4 toggle switches
and the LEDs on the board show the
position of the point. The module comes
with the switches separate in a plastic
bag because they are too tall to post in
out small posting box. You can solder
the switches to the board or fir them to
your control panel and use 3-core ribbon
cable. The two outer
wires of each point are connected to the
2-terminals above and the 4 middle wires
of the points connect to the 2-terminal
block on the left of the module. oooooooooooo000000000000000000oooooooooooooo
CHOICE
NUMBER 25: KATO
Modules are available for this project
from
The CIRCUIT
Understanding KATO
The
KATO Throttle is called KATO POWER PACK
A
Kato 22-018 Power Pack is available on eBay for $40.00 shipped and
you will need an AC plug pack
The KATO 12v AC plug pack costs $25.00 to $40.00 on eBay BUT is for 100v AC and is not much use in the
rest of the world. The advertisers don't tell you it's for 100v AC.
There is NO 240v version.
What you need is a transformer as shown above. It converts 240v AC
to 12v (or 15v) at about 1 amp.
Now we come to adding a KATO TURNOUT CONTROL SWITCH. The photo
below shows
5 switches added to a KATO Power Pack.
These switches have two studs on each side and they click into the
studs on the right-hand-side of the Power Pack. The two terminals
called 0v and 12v on the circuit above are the studs and are not 12v
(as explained above) but possibly about 14v pulsed DC.
The KATO 24-840 Turnout Control Switch (shown above) is
actually a PASSING SWITCH
and only makes contact when the lever is a little-bit down from the
top and a little bit up from the bottom. These switches cost about
$8.00 on eBay.
If you don't have a KATO POWER PACK, you can buy a Kato 24-829
Accessory Adapter. It is also called
Kato 24-842 DC Converter.
It contains 4 diodes and converts an AC voltage to PULSED DC. The
Passing Switches will then send the pulsing DC "around one way" to
the point via a pulse or "around the other way" via a pulse. Here is
a Kato 24-829
Accessory Adapter clicked onto two
KATO 24-840 Turnout Control Switches.
You can see the DC Converter has click fittings on both sides
If you have 15v AC from
a "TRAIN TRANSFORMER," you can connect the 15v to the two
wires coming from the back of the
Kato 24-829
Accessory Adapter. If you have 12v DC, you can
connect to the two wires (around either way) but the output will be
10.5v DC. This will be sufficient to pulse the KATO POINT MOTORS
(solenoids).
Talking Electronics has designed a number of modules to
replace KATO modules.
THROTTLE WITH PWM
4-POINT CONTROLLER FOR KATO POINTS
KATO DISTRIBUTION BOARD
$18.00 plus $4.50 postage
Buy Here oooooooooooo000000000000000000oooooooooooooo
|
ACTIVATING A POINT This discussion involves up-dating a manual point to an automatic point or motor-controlled point. It can also be called: Moving a point, changing a point, activating a turn-out or controlling a point. All the modules to do this are on this page and we are going to give you a list of the different modules and what they do. If you have solenoid activated points, this discussion is not for you. We have separate modules to activate solenoid points for PECO points and KATO points. See the index above for CDU Modules. If you have DCC, (DIGITAL CONTROL) we have modules that connect to the track and are activated from the track signals. If you have DC control of your locos, we have slow activating servos requiring control lines from your console to each point. Your console will have LEDs to show the position of the point. We also have a servo that connects to the track to leach energy from the track to charge a battery that controls a servo. The module is contained in a HUT and is activated by an IR remote control (from an old VCR) and you can walk around your layout and activate the points. The Module is called IR Point Controller. |
COMPUTER CONTROLLED
POINTS COMPUTER INTERFACE MODULE with OPTO ISOLATOR and FRONT PANEL $45.00 usd plus $11.00 usd shipping. Buy Here You have a computer with 6 spare outputs and you want to control 3 points. The computer has 0v (low) to 5v (high) output and a turn-out requires a voltage as high as 25v . You do not want to get this high voltage near your computer. The answer is our COMPUTER INTERFACE MODULE with OPTO ISOLATOR. This set of modules does 3 things. It takes 6 lines from your computer to operate 6 opto isolators and the output from each OPTO ISOLATOR delivers a signal to the COMPUTER INTERFACE MODULE. The COMPUTER INTERFACE MODULE has a 26v circuit to operate solenoid points and a memory circuit to control LEDs to show the position of the point. All you need to do is program your computer program to deliver a pulse of any duration from each output and the first output will change the point to MAIN and the second output will change the point to SIDING. The COMPUTER INTERFACE MODULE and OPTO ISOLATOR. modules require an input voltage 9v to 15v and the COMPUTER INTERFACE MODULE has an inbuilt automatic pre-voltage power supply to convert the 9v -15v to 26v.
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WIRING A POINT MOTOR Point Motors take a high current when they are operated for the very short time they are intended to work. Most point Motors have a coil resistance of about 3.8 ohms and when operated on a supply of 12v, this will allow 3 amps to flow. Normally, wiring for 3 amp will require medium duty hook-up wire because the current will be flowing for a long period of time and thick wire prevents it getting hot. But with a solenoid-type Point Motor, it is only activated for less than a second. This means thin hook-up wire is perfectly suitable. 3 metres of thin hook-up wire will have a resistance of about 1 ohm and if 3 amps flows, the voltage drop across the wire will be 3 volts. But most Capacitor Discharge Units are charged to a voltage higher than 12v and can be 24v. If we take 24v, the current will be 5 amps and the voltage drop will be 5v. This gives the solenoid 19v. The Capacitor Discharge Unit is designed to give 24v at the beginning of the pulse and gradually drop to almost zero after less than 1 second. This give the solenoid Point Motor an initial kick to start moving and then the current gradually reduces so the "end clunk" is not so strong. This means the wiring to the Point Motor can be almost any thickness as it has very little effect on the operation of the solenoid. |
Talking Electronics has produced a number of different TRAIN THROTTLES.
Most locos take about 300mA to 500mA and need a voltage of about 12v for full
speed.
There are two types of TRAIN THROTTLE: ![]() Two Amp Power Supply circuit diagram. It is also called 2-amp THROTTLE ![]() The completed project, showing the placement of the parts The input voltage can be AC or DC. The DC voltage needs to be at least 16v6 to get 12v DC out. If you supply 17v to 20v DC, nothing will be damaged. Just the 470R resistor will get slightly hotter when the input voltage is above 18v. The 2-Amp POWER SUPPLY project is
HERE You will need a double-pole double-throw toggle switch to reverse the train. Ask for it. $2.50 extra.
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TRAIN THROTTLE No2.
(kit: $18.00 with leads)
Click Here
to order.
The $2.50 plug Pack above was purchased as 12v @ 1 amp. It was
easily opened-up via a screw and clip, to reveal the PC board shown
below.
oooooooooooooo0000000000000000000000000000oooooooooooooooo Kit: $28.50 plus $6.50 postage.Click HERE to buy a kit. Built and Tested: $35.00 plus $6.50 postage. Click HERE to buy a module. This is our latest design with forward and reverse via the yellow CONTROL POT. This project does not need a reversing switch as the pot provides zero speed when at 12 O'clock and reverse when turned to the left and forward when turned to the right. The output is Pulse Width Modulated (PWM) to give the loco smooth starting. By this we mean the motor gets pulses from the throttle that allow it to start very slowly. The module is capable of delivering 3 amps (due to the thickness of the tracks) and the power diodes are 5 amp. Additional heatsink fins will be needed for currents above 2 amp. But we suggest a 1-amp supply for most loco's. The 4 FETs on the output bridge are capable of handing more than 10 amp and the trackwork on the board can be modified to handle 5 amps by soldering tinned copper wire along the tracks identified with additional solder pads. This means the controller can be used for garden layouts where the loco will draw 5 amps. If you want to control more than 5 amps, you will need to connect the supply directly to the MOSFETs in the bridge and by-pass the 5 amp diodes. The switch at the right is the on-off switch. The two LEDs on the board indicate forward and reverse, in case you cannot see the loco on a large layout.
All the digital signals are controlled (and generated) by the microcontroller and
the pot determines the timing of the waveform and the
activation of the H-bridge. This version was requested by a customer. He wanted the control facing the front: ![]() ![]()
The cost is the same for either module
but you must specify which version you want. The switch and knob are
not attached when posted as the module must be less than 2cm high
for posting in the box we use.
You can request the following type if you do not want to use the rail joiners:
This version is cheaper and has improvements. The throttle knob and the reversing switch comes out the front so you can fit the module to your console. The module will pass about 2 amp as the two 1N4004 protection diodes are in parallel. The throttle goes down to zero due to the clever circuitry with the 555 IC. It is also cheaper. Cost of fully built and tested module is $15.00USD plus $8.50 USD shipping and includes the knob. Price $22.00 AUD and $6.50 AUD postage Click HERE to buy a module ![]() ![]() ![]() The throttle above can also be bought with CURRENT LIMITING for $2.00 extra. The pot on the module is rotated clockwise to increase the current to a maximum of 1.5 amp. When it is rotated anti-clockwise the current is reduced to less than 100mA. It works like this: Suppose you have a 12v supply that is capable of delivering 10 amps. If a short-circuit occurs on your layout, the throttle module above will pass a high current and the diodes will burn out. With this module, the current will be limited to 1.5amp and nothing will be damaged. This module will also allow you to test new track for shorts at points or other new sections of track. Simply reduce the maximum current and you will be able to drive the loco and if a short-circuit occurs, the maximum current will be limited to about 300milliAmp or so. Cost of fully built and tested module is $17.00USD plus $8.50 USD shipping and includes the knob. Price $25.00 AUD and $6.50 AUD postage Click HERE to buy a module
UPGRADE YOUR CONTROLLER
Some of the following
controllers deliver just 7v and some are up to 16v AC output and/or
16v DC output. They all have forward/reverse on the control handle
so the only improvement you will get by connecting to the THROTTLE WITH PWM module above is PWM.
PWM will allow your train to start very slowly as the pulses
overcome some of the friction by pulsing the motor with strong
bursts and this gets the train moving.
The Transformer ooooooooooooooooo000000000000000000000ooooooooooo
STATION STOP
MODE 1 |
The output of the
servo moves about 70 degrees as this will give the greatest "throw."
You can select the hole on the arm to produce the travel you want.
Here is a set of gates controlled by 4 servos.
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DCC stands for Digital Command Control and basically
means you can control more than one train on the same track.
The next cheapest "add-on" is our DUAL DCC CONTROLLER +5 to operate two DCC locos plus 5 other items such points. It costs $53.00 and it has 5 buttons to operate up to 5 DCC points and the module shows the position of the point via LEDs, plus images on the module of the tracks. xx Operating a Point - Controlling a Point - a Turn-Out If you have a Peco Point or other point using a solenoid, you can operate this Turn-Out with your NCE Power CAB Controller by fitting our DCC Capacitor Discharge Unit.
It is called: DCC POINT CHANGER for a SOLENOID POINT (with CDU)
and will operate a Peco or other
solenoid point:
// ????le with a relay that you can
toggle from the "5 button DCC controller" shown above. This will
allow you to operate station lighting or motorised animation
devices.
The next "add-on" is a DCC module with 5 buttons to operate
1,2,3,4 or 5 DCC points. You will need to buy the
$25.00 DCC Point Controller called a Capacitor Discharge Unit or the
DCC Point for $35.00 using a servo to operate the point.
Here are the modules in more detail:
This Dual DCC controller will control 2 locos at the same time and
is an ideal way to create a DCC set-up. And the cost is just $43.00
AUD plus $6.50 posted worldwide.
This is a 1amp decoder NOT 500mA as most of the
advertised small decoders.
You can turn a DC Loco into a DCC loco with this universal Motor Decoder for
$18.00 plus $4.50 postage worldwide.
Converting AC Locos
Here is a video showing how to fit a bridge rectifier to deliver
pulsating DC to the filed winding:
The only problem with fitting a bridge rectifier is this: At
low velocity the energy delivered to the field winding will be very
small and thus the motor will be very weak. The decoder delivers
pulses of energy to the motor and the pulses are actually at full
strength but for a short period of time. You can put 100u to 1,000u
electrolytic across the field winding to see if it improves the
performance. |
DCC POINT CHANGER
using a servo Talking Electronics has produced a module that detects the DCC signal on the track and changes a point. But to explain this we have to start at the beginning. To operate the DCC Point Changer you need a DCC Controller such as NCE POWER CAB. There are a number of suitable types, BUT NOT A HORNBY CONTROLLERER. The Power Cab has a keyboard to select the address of a loco. But the same range of numbers can be used to access other items such as the operation of a point. We have used address "40" to operate our DCC POINT CHANGER using a servo, shown below. You can have 1, 2, 3, 4, or 5 DCC POINT CHANGERS on this address and to operate each point, the keys 1, 2, 3, 4, 5 are used in TOGGLE MODE. By pressing key 1, the first POINT CHANGER will activate the point. But you will not know the position of the point, if you cannot see it move. So we have a DCC Point Identification module that picks up the signal from the track and shows the result on a display. ![]() You need
4 things:
TO SERVO You will also need a
connection to the track to pick-off the signal< to operate the DCC
Point Changer and also power the servo.
Track Pick-Off MkII. It has two springy clips
that touch the inner parts of the rails and make electrical contact. .
1. You need a controller such as NCE Power CAB that uses NMRA DCC digital signals. 2. You need the DCC POINT INDICATOR module (the module shown above) 3. You need a DCC Point controller. This can be purchased from Talking Electronics and is connected to the track to pick up track voltage and DCC signals. The DCC Point controller can be designed to operate a solenoid point (commonly called a Point Motor and is actually a solenoid that needs a CDU (Capacitor Discharge Unit) to operate it remotely. Or the DCC Point controller can be designed to operate a servo with slow activation to change the position of the point. There are two different types: DCC Point controller - for solenoid or DCC Point controller - for servo HOW IT WORKS 1. The DCC Point Indicator module is connected to the track using the TRACK PICK-OFF BOARD and track joiners. 2. The DCC Point controller module is connected to the track using the TRACK PICK-OFF BOARD and track joiners and the output is connected via 3 wires to the solenoid or the servo is connected to the arm on the point via a linkage. You can have 1, 2, 3, 4 or 5 modules that control the points and they can be any mixture of DCC Point controller - for solenoid or DCC Point controller - for servo 3. On your< NCE Power CAB (called a controller) select address 40. 4. Now press button 1 and the DCC Point controller connected to button 1 (via the program in the chip on the DCC Point controller module), will activate the point to the branch line. Press button 1 again and the module will activate the point to the main line. 5. At the same time, the LEDs on the DCC Point Indicator module will show green or blue to correspond to branch line or main line. SIGNAL PICK-UP oooooooooooooooo000000000000000000000000000000ooooooooooooooooo
DCC POINT CHANGER for a SOLENOID POINT
The module takes a small amount of current from the track to charges the
4700u electrolytic to 25v. .
ooooooooooooooooo0000000000000000000ooooooooooooooooo ![]() ![]() ![]() Your
controller connects to the module
This module fits between your controller and the track. |
This projects allows
you to use any old IR remote control from a TV or VCR to control your points.
You can walk around your layout while someone is driving
your train and control the destination of the train.
18/8/2022 |
We have designed 4 different CROSSING LIGHTS MODULES to
cover the different requests from customers.
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LOCO STOP This module is for a 2-aspect signal. See below for 3-aspect signal module. This is another clever design. The module, fully built and tested for $25.00 usd plus $5.00 shipping. You will also need a signal. There are 5 different signals shown in the images below: Signal A is a dwarf signal 20.5mm high Signal B is a dwarf signal 13mm high Signal C is a dwarf signal 7.5mm high D is a signal head 13mm high E is a signal head 7mm high The signals are connected to the module with about 15cm of very fine wires. The signal heads come with poles that you glue to the head. The module also comes with a reed switch on 1.5m of very fine screened audio lead and 2 super magnets. Click HERE to order the module, reed switch and a 2-aspect signal. When ordering, you will need to include which type of signal to be connected to the module.
The circuit is used on a model railway layout to automatically
control a 2-aspect signal to add to the features of driving around a
layout.
The reed switch is placed a short distance in front of the signal so the loco has to stop and wait for green. You can add an accident or track-repair after the signal to provide a purpose for stopping the train.
LOCO STOP
for a 3-aspect
signal. (module coming soon)
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Train Detectors are mainly used to watch the passage of a train
around your layout via a series of LEDs on your console. Here's how to decide on the module you need: Firstly you have to work out what you want to turn ON when the train approaches. Is it LEDs or globes or a motor? Then you have to know what current your device takes. Normally this is of no concern, but some of the Train Detector Modules have a transistor switch and the capability of the switch may be limited to 50mA, 100mA or 200mA. One module will handle 3 Amps or more. Then you have to decide if you want REED SWITCHES or Infra-red sensors. The simplest is a set of two reed switches. This will detect the train in both directions. They are placed either side of the crossing and detect the on-coming loco. If you want to pay a little more, you can have 2 IR detectors. Then you have to decide if you want a DELAY feature. Some modules have an on-time (also called a DELAY) from 1 second to 30 seconds. You may want to activate a set of lights at a station as the train passes or a windmill or a set of crossing lights and some of our modules provide an activation for a period of time. You select the DELAY TIME by adjusting the mini trim pot on the module. Now that you know all the features of the modules, you can select the right one to suit your application. There is one final option. Two modules have an ISOLATION feature where the output (the output is a SWITCH) is totally isolated from the electronics of the module and this means you can turn on a device that has its own power supply. The output of some Train Detector modules is a SWITCH - just like the wires from a reed switch, or the connections on the output of a relay. Other Train Detector "supply" the current (and voltage) to the module being activated. And this "supply" comes from the power rail of the Train Detector module. If you do not know what you want, you need to email us with your details so you get the correct module. THIS IS HOW THE TRAIN DETECTOR WORKS: When the Train Detector module detects a loco, the resistance between the two output connections is very low. (The OUTPUT of the Train Detector module). We say "low" because the switching device may be a transistor (in the circuit of the Train Detector). It will be zero ohms when the switching device is a relay. When the "switch" in the Train Detector module is a relay, you can connect the two wires (to the device you are activating) around either way. But in our case the relay is a CMOS relay and the connections must be around the correct way. When the "switch" in the Train Detector module is a transistor, you must connect the two wires (to the module you are activating) around the way we will explain in an accompanying diagram. This is because the transistor only becomes a "switch" in one direction. If the module you want to control is powered by a different power supply to the supply for the Train Detector, you will need to buy the OPTO or RELAY VERSION. This version is classified as ISOLATED. Finally, you need to know if you want the Train Detector to be able to switch a very small current - such as 50mA or a higher current - such as 500mA or 1 amp. If you buy the relay module, it will switch everything, but the other modules are cheaper. Finally, you can buy a module that remains active (switched) for 1 sec to 30 seconds. This is called DELAY TIME or ON-TIME. IR DETECTOR Since you cannot see the Infra-red beam of the Train Detectors, we have designed a detector that you move around in front of the beam and work out where it is the brightest. This detector also works for 38kHz beams. It is essential for detecting problems. Ask us about the kit. And we also have a LED TESTER that will illuminate and test LEDs and also test leads for continuity. Ask us about the kit. Now we come the modules: THE FIRST TYPE This is our simplest and cheapest TRAIN DETECTOR. It is called TRAIN DETECTOR with reed switch. It is fully built and tested and costs $8.00 plus $6.50 postage. ![]()
You will get the module on a Printed Circuit Board. The
photo shows the prototype with one reed switch and 2 super magnets 12mm
diam x 1mm thick.
It comes with a reed switch on 1500mm lead and two very strong super
magnets that fit under two of your locos.
If you have 2 tracks you need to use
our 40kHz Train Detector with 40kHz coding and our special 22cm sensors. This
is the only sensor that will reliably detect across 2 tracks and not be
affected by ambient light.
The "evermodule" is just a flip flop without any delay or
train detection. You need the TRAIN DETECTOR module to get the
full-operations features, you want.
This design also comes with a TOGGLE feature where the
first reed switch turns the module ON and the second reed switch turns
the module OFF. This is ideal for activating STATION LIGHTS or any other
attraction that needs to be activated when the train passes.
THE SECOND TYPE
THE THIRD TYPE
You can also get this module with 12 inputs and 12 outputs.
The 12 LEDs are in a row and you can see them illuminate in-turn as your train
executes the circuit.
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THE FOURTH TYPE - Reflective Detection This module also supports a reflective module
containing two LEDs that can be placed between the rails:
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The second isolated module uses a relay and can pass 1Amp via its output
terminals. This is idea for larger loads such as sound modules, motors,
and motorised point controllers.
THE SEVENTH TYPE
- 5amp capability on the output pins.
The receiver only detects a 38kHz signal, similar to your TV remove control and thus the project is not affected by room illumination. The first 555 IC on the module produces the 38kHz signal.
All our train Detector modules can be connected to LED
Lamps in a Station or roadway and will turn ON when activated by the
train.
If you are not sure about the value of resistance (the
value - in ohms - of the resistor), start
with 2k2.(red-red-red) Lamps with "grain of wheat" filaments can also be used (they do not need a resistor) but only up to 6 on a Train Detector module.
THE NINTH TYPE
This TRAIN DETECTOR module comes with two reed switches and
2 very powerful super-magnets that you
place under the loco. The super-fine screen leads to the reed switches
are 1m and about 1.5m in length. |
The module also has CROSSING LIGHTS sockets and comes with 2 LEDs for
demonstration purposes, so you know the module is working. You may need a resistor in the positive (red) lead of some lamps and if you are not sure, add a resistor and lower the value of resistance until you get the required brightness. The module will allow up to 10 station lights to be connected to the output terminals.. Here is the list of modules: TRAIN DETECTOR with reed switch. Fully built and tested: $8.00 plus $6.50 postage.
6 TRAIN DETECTORS (kit) . . $21.00
(no delay)
TRAIN DETECTOR IR using 4n25 . . $24.00 (isolated
type)
(no delay)
TRAIN DETECTOR IR using RELAY . . $25.00
(isolated type) (with delay) |
FLASHING AND ROTATING LIGHTS Talking Electronics has produces a number flashing and rotating lights modules. Only pay once for shipping multiple modules. email Colin Mitchell before buying modules.
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HOUSE LIGHTING - Random
Lighting g This module drives 6 white LEDs in random and you can adjust the on-off times. 3 of the LEDs come on 1 metre of wire with the second LED on each wire at 800mm from the module. Cost of the module, fully wired and tested: $15.00 plus $4.50 postage Contact Colin Mitchell before buying for international costing and postage availability. This was requested by a customer who wanted to illuminate his row of houses with an on-off lighting effect to simulate the presence of people. ![]()
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LIGHTHOUSE LIGHT Add this module to your layout for a very effective Lighthouse Beacon. Double-faced super-bright 1206 LEDs can be mounted in all types of models to give the effect of a rotating light. The result is very effective. Microcontroller circuit with 5v regulator. Input voltage can be 8v to 15v DC or 9v battery. The latest module has a mini slide-switch to select single flash or double-flash. (not shown in photo below)
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CARRIAGE LIGHTING
Add this module to a carriage for a very realistic
lighting effect. |
to
Index
Theory, Test Gear
& More Projects
MATRIX BOARDS Talking Electronics has produced a lot of matrix board in all sorts of sizes and shapes so the board is ready and neat for the layout of components. These boards cost just $2.00 for the small boards, $2.50 for the medium size and $3.00 for the larger boards. Simply email Colin with the number and size and they can be sent to you. Click Here to order
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THEORY
THE MULTIMETER I test all my projects with a $5.00 multimeter !! WHY??? Because an analogue multimeter puts a load on a circuit and the reading MUST be genuine. Secondly, an analogue multimeter will show fluctuations in a circuit and show when a certain part of a circuit is not maintaining stability. And thirdly, an analogue multimeter will respond to changes and pulses much faster than a digital meter. Lastly, if I can design and test a circuit with a cheap meter, everyone else should be able to do the same when using a more-expensive meter. Finally, an analogue meter lasts a lifetime. And if you damage it, the cost is only $5.00 And you get 500mA range, a digital meter gives 200mA. Analogue Meters are on eBay I have digital meter when I want to read voltages accurately.
This is how you do it.
Current flows through the multimeter from the
positive probe to the negative probe and the arrow on top of the meter
above shows this direction.
If you cannot remember how to connect a multimeter
when testing CURRENT, tilt it slightly so the positive terminal is
higher than the negative terminal and lay the red probe on the bench,
HIGHER than the black probe. |
THEORY
SERVOS
![]() The servo has a "pot" as the feedback but it does not have any "stops" and thus the wiper passes the end of the curved track. I tested this servo by trying to find the "dead spot" where the servo did not respond to a position that would normally be past either of the "end-stops." The program in the servo detects when the wiper is not on the track and sends the arm to a starting position - proving this servo is the best one to buy. "No stops" means the servo will not get jammed if it is forced (by an outside force). Sometimes, when these servos are used in a Robot-Fighting situation, they get forced to move (when in a collision) and this jams the gears. This servo does not have that fault. This servo also operates slowly (when connected to some of our modules) and does not "jitter" when used in our projects. |
THEORY
The
reed switch only detects a magnet when the magnet is in
positions A and
C. This
is because the magnetic flux produced by the magnet "hits"
the left or right reed and magnetises it in a process called
TEMPORARY MAGNETISM or INFLUENCED MAGNETISM and since the
other reed is not magnetised, the two reeds "stick
together." When the magnet is in the centre of the reed,
both reeds get magnetised by the North pole of the magnet
and they do not make contact. |
THEORY
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THEORY
This is just one way to connect it to a circuit when you want to be able to connect a Hall Device or a reed switch to the same input terminals of a project.
The Hall device is being
used in an unusual way in this project, with the output connected to
the "supply lead." |
TEST EQUIPMENT
LED TESTER This project tests LEDs and tests for continuity and tests for other things as well. It's a very handy piece of test gear. Note: The two lithium cells are 6v for the supply. See the full project HERE LED Tester Kit
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TEST EQUIPMENT CONTINUITY TESTER This project tests for continuity and resistance and other things as well. It's a very handy piece of test gear. Note: The two lithium cells are 6v for the supply. See the full project HERE
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PROJECT TRACK PICK-OFF Track Pick-offs are available from Talking Electronics for $2.00 plus postage. This Printed Circuit board is fitted between the sleepers and has contacts to touch the rails so the voltage on the track can be monitored or delivered to a project. If the current taken from the track is very small, it will not interfere with the operation of the train(s) on the layout and is called LEACHING. A little bit of power is taken from the track and this saves running wires all the way back to your control panel. Talking Electronics has designed 2 of these TRACK PICK-OFF boards: Track Pick-Off MkI has two track joiners soldered to the board and this is fitted between two sections of your layout. The images below show this board and how it it fitted to the track:
Here is the module connected to a project:
If it is not easy to connect the track joiners to
your layout, we have:
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TEST EQUIPMENT TRACK TESTER This project tests the voltage on your track. It's another very handy piece of test gear. See the full project HERE The Track Tester kit costs $10.00 AUD plus $4.50 AUD postage. The Track Tester is also available ready-made for $16.50 USD (posted) It alerts you to the presence of DCC via the piezo diaphragm and the voltage of your track at all parts of the layout. Click Here to buy a Track Tester.
MINI
TRACK TESTER $12.00 usd plus $6.50usd shipping. Click Here to buy Track Tester with 4-Digit Display Our Latest Track Tester has a 4-Digit Display to show the track voltage. It shows DCC track voltage as well as DC track voltage as well as LEDs to show the positive rail. The display illuminated when the left probe touches the positive rail. The piezo diaphragm allows to you hear any noise on the rails including DCC commands.
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TEST EQUIPMENT
OVER-CURRENT DETECTION Requested by William Hicks: This circuit detects when the tracks are overloaded by too many trains. ![]() Note: Each 1R resistor needs to be 0.5watt 0R22 needs to be 5watt!! The circuit will drop 1.4v when full detection-current is flowing. Here is the simplest over-current circuit:
Kits
are available for this
project from
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CURRENT TRIP |
FLASHING RAILROAD
LIGHTS This circuit flashes two red LEDs for a model railway crossing. ![]() ![]() |
FLASHING LIGHTS FOR MODEL
RAILWAY CROSSING: A flashing LED is used to create the timing for the flash-rate and the transistor provides the alternate flash for the second set of LEDs. The first circuit comes off the web, but Colin Mitchell doesn't think it will work. See his circuit below. ![]() The top two 1k resistors are current-limiting resistors and can be increased if you want the LEDs to be dull. The 2k2 makes sure the two LEDs are completely turned-off because the flashing LED draws a small current when it is off and this shows in the two LEDs. The lower 1k may need to be reduced to 470R to completely turn the transistor OFF. The other circuit does not have any of these features. The flashing LED has to be an ON-OFF flashing red OR green LED. Not a red-green flashing LED or a RED-GREEN-BLUE flashing LED. The flashing LED actually has an in-built resistor and will work on 2v to 5v. But we are using its feature of "taking a small current" when illuminated and then "taking almost zero current" when not illuminated, to "switch the transistor." You can get the CROSSING LIGHTS plastic mouldings from Talking Electronics. They will take 3mm LEDs. Cost: $6.00 for 2 Crossing Lights with 4 LEDs and 2 metres of fine 0.25mm enamelled wire. . You need to "push-out" the red lens and fit the 4 x 3mm red LEDs and carefully solder wires to the LEDs.
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TRAFFIC LIGHTS Here's a clever circuit using two 555's to produce a set of traffic lights for a model layout. The animation shows the lighting sequence and this follows the Australian-standard. The red LED has an equal on-off period and when it is off, the first 555 delivers power to the second 555. This illuminates the Green LED and then the second 555 changes state to turn off the Green LED and turn on the Orange LED for a short period of time before the first 555 changes state to turn off the second 555 and turn on the red LED. A supply voltage of 9v to 12v is needed because the second 555 receives a supply of about 2v less than rail. This circuit also shows how to connect LEDs high and low to a 555 and also turn off the 555 by controlling the supply to pin 8. Connecting the LEDs high and low to pin 3 will not work and since pin 7 is in phase with pin 3, it can be used to advantage in this design.
Both 555's are wired as oscillators in astable mode and will oscillate ALL THE TIME when they are turned ON. But the second 555 is not turned on all the time! The first 555 turns on and the 100u is not charged. This makes output pin 3 HIGH and the red LED is not illuminated. However the output feeds the second 555 and it turns on. Output pin 3 of the second 555 turns on the green LED and the second 100u charges to 2/3 rail voltage and causes the 555 to change states. The green LED goes off and the orange LED turns on. The second 100u starts to discharge, but the first 100u is charging via a 100k and after the orange LED has been on for a short period of time, the first 555 changes state and pin 3 goes LOW. This turns on the red LED and turns off the second 555. The first 100u starts to discharge via the 100k and eventually it changes state to start the cycle again. The secret of the timing is the long cycle-time of the first 555 due to the 100k and the short cycle due to the 47k on the second 555. |
4 WAY TRAFFIC LIGHTS
This circuit produces traffic lights for a "4-way" intersection. The seemingly complex wiring to illuminate the lights is shown to be very simple. This circuit is used in the next article. ![]() |
4-Way
Traffic Lights Kits
are available for this
project from
This wiring diagram shows how the LEDs are connected in the over-head light. All the anodes are connected to the black wire and the cathodes emerge as Green, Orange and Red. The 4-screw terminal block is looking at the where the wires enter the terminals and this is clearly shown in the photograph above. |
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This project operates crossing
lights automatically when the train enters the crossing and turns them
off automatically. The flash-rate can be adjusted as well as the
brightness of the lights and the overall length of time for the
flashing. No other module on the web offers these features.
Two LEDs on the module indicate when the lights are flashing and the module comes with 4 extra LEDs for those who have bought crossing signals without the LEDs installed.
The circuit has a number of very clever features. .
It uses two 555 ICs to provide all the functions. The
signal diode on the first 100u discharges the 100u quickly when the
circuit turns off so the timing can restart again with full duration.
The module is available fully-built and only needs to be connected to
12v DC. Connect the reed switches or Hall devices to the input terminals
and switched ON.
TWO versions of this project are now available because some 2-aspect lights have a black wire that goes to the anode of each LED via a resistor and some are wired with the black lead to the cathode of the two LEDs. The difference between the two PC boards can be clearly seen by the white frame around the output pins.
A new version of JIM'S CROSSING LIGHTS (called ver5) has been produced for customers who cannot work out which type of lights they have installed. It has a change-over switch and works with both types - very clever !!! ![]() The image above shows the fully built and tested module. It comes with 2 reed switches on 1200mm leads and 2 super magnets for $25.00 usd plus $6.50 usd postage. Order a module: Jim's Crossing Lights for TypeA&B lights Connecting the Lights: ![]()
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