DCC

Accessory Decoder


In a digital model can be maintained although some changes with the analog control of turnouts, signals and accessories, if you want to control from the command station and set routes or control from the computer, you will need a decoder to read the signal from the DCC command station and activate properly accessories or turnouts. Normally an accessory decoder controls 8 outputs for 4 turnouts or signals

Here you can find different types of accessory decoders

Accessory Decoder for 4 turnouts and signals or 4 semaphores
Turnouts Decoder for 2 turnouts
Servos Decoder for 4 servos
ServoPoint Deco for turnouts with servo
Semaphores Decoders for semaphore with slow on / off and flash
PAN-Sound DCC decoder for railroad grade crossing with sound
Peripheals DCC Decoders with transistors, adjustable output, and so on. Chained
MOT-VREG Adapters for accessory decoder outputs
Turntable Turntable decoder
PpP Decoders Decoders for semaphores, turnouts, lighting.







Decoder for 4 turnouts and signals


In Internet there are several designs of accessory decoders, can be found among others in MERG, Estacion Digital, CTMS or Le monde du DCC

Basically they are all variations of the same design with a PIC16F84 which use the same software or with some variations. I also I made my own variation of the design of the decoder by adding a button that has been pressed while you program the decoder, so we should not disconect the other when you program it and I've changed so that the two outputs that control an accessory are not activated at the same time so it can be used both for turnouts or semaphores.



Schematics and PCB design can be downloaded here, if you want to know how to make PCB or identify the components, you can read one of these tutorials.

For the assembly and testing of failures can follow this step by step



I have separate the DCC data entry to use a transformer to feed the accessory decoders and do not overload the booster, thus consuming only to power the optocoupler. If you want to feed from the booster only thing that connect the power input to DCC input. The 2200uF capacitor allowed to have a good reserve of power to activate the turnouts, the ULN2803 can give in their outputs 500mA if You need more power can weld another ULN2803 above the existing circuit. Additionally, I have placed twice ground connectors in case you want to use from a panel push buttons to activate manually turnouts like this:

To program the PIC16F84 can use the HEX file that is here or another of the links above. If you have a central Lenz, you can use a PIC16F628 and the HEX file that is in MERG, in this case does not need the pushbutton.

To program the decoders ought to press the button when push the programmingg key at the commnand station, once programmed the LED will light. The CV of decoders start in the CV513, here you can see the main CV. The time of activation of the outputs will be 10ms by the number programmed into your CV, if you program a value of 0, you'll get a fixed output (for the semaphore).


Semaphores with slow on / off


If you want to get a slow ignition of the lights in your semaphore, you can program the PIC with the file that is here to get 4 semaphore red / green in which you will choose the maximum brightness and speed of light, or you can also control two semaphores or 3 lights type RENFE controlling the track, all using the accessory decoders with or without the permission programming pushbutton.



You can also download the manual and you can see a video of how it works, thanks to Peli







4 servo decoder v.2


To move the turnouts with a slow motion effect can be used servos. You can see a decoder for two servos on the page from Heiko Schroeter, it also allows controls the frog of the polarized turnouts or the ServoPoint for a single servo. The PCB and the CV programming can be found in Different-ways

If you have no need to control the frog of the polarized turnouts, you can mount this decoder that allow to control 4 servos in which you can set the speed of movement and the angle of movement.

You can use the same PCB from Different-ways or better this another scheme that already incorporates the bridge of diodes and is a smaller assembly



The program and the PCB can be downloaded here, if you want to know how to make the PCB or identify the components can read one of these tutorials. When you prgram the PIC12F629 keep in mind that it has to preserve the value of the last position, so it might be desirable to first read the PIC and save value and then check it once programmed.

The connectors that carry the servos vary according to the brand, here you have a few:



Carlos Viva sent me his design for this decoder servos:







2 servos with 2 relays decoder


Haakon asked me to modify the 4 servo decoder software to get a 2 servo decoder with relays to control the frog of the polarized turnouts that changes the relay in the middle position.


you can set the speed of movement and the angle of movement.

The program and the PCB can be downloaded in Collaborations section with the name of Servopoint2. When you prgram the PIC12F629 keep in mind that it has to preserve the value of the last position, so it might be desirable to first read the PIC and save value and then check it once programmed.







ServoPoint


The problem of using servos to move the turnouts is the way to polarize the frog if needed, can be done, for example, by installing a switch as a final career. Another problem is to move them by hand because the 4 servo decoder has no buttons to move it manually..

ServoPoint allows to use a servo and at the end of the movement gives a pulse to a small bistable relay that permits properly polarize the frog, leaving another switch for free use, such as signaling the position of turnout, and with a pushbutton you can manually move the servo.

The program and the PCB can be downloaded here, if you want to know how to make the PCB or identify the components can read one of these tutorials. When you prgram the PIC12F629 keep in mind that it has to preserve the value of the last position, so it might be desirable to first read the PIC and save value and then check it once programmed.

Salus was the one who asked me to adapt the software's of 4 servo decoder to move the turnout and polarize the frog. Here you have his design, the DEC-SRV1, which improves the mine because is optocoupled and adapted to move turnouts taking the electronics incorporated. You can also watch a video with its operation




ServoPoint_Opto


Version of ServoPoint with optocoupler:

The program and the PCB can be downloaded here, if you want to know how to make the PCB or identify the components can read one of these tutorials. When you prgram the PIC12F629 keep in mind that it has to preserve the value of the last position, so it might be desirable to first read the PIC and save value and then check it once programmed.







Decoder for semaphore with slow on / off


If you want to achieve a slow turn on of the lights of semaphores you can mount this small decoder for 2 red / green lights with which you can choose the maximum brightness and speed of ignition, or you can also control a 3-light RENFE type lights with track control or used to control 2 lights maneuvering semaphores type RENFE.

If you want to show more light aspects in your semaphores, you can see the new UniSemaf . If you need more semaphores at a decoder, you can see UniSemaf-648 or other circuit with PIC 16F628 or 16F84

You can use the same PCB from Different-ways or better this another scheme that already incorporates the bridge of diodes and can be powered from the DCC or from a power supply



The manual, program and the PCB can be downloaded here, if you want to know how to make the PCB or identify the components can read one of these tutorials. When you prgram the PIC12F629 keep in mind that it has to preserve the value of the last position, so it might be desirable to first read the PIC and save value and then check it once programmed.



UniSemaf


This decoder allows 4 lights and up to 8 different aspects with slow effect of the lights and flash, and you can choose freely the lights and the aspects programming their CV. These are some semaphores that can be achieved:



The manual, program and the PCB can be downloaded here, if you want to know how to make the PCB or identify the components can read one of these tutorials. When you prgram the PIC12F629 keep in mind that it has to preserve the value of the last position, so it might be desirable to first read the PIC and save value and then check it once programmed.



UniSemaf-648


Semaphore decoder with up to 8 lights and 32 fully configurable aspects with PIC16F648 (24 aspects with the PIC16F628). With slow effect of the lights and flash, and you can choose freely the lights and the aspects programming their CV. Uses the same PCB as decoder for 4 turnouts and signals



The manual, program and the PCB can be downloaded here, if you want to know how to make the PCB or identify the components can read one of these tutorials.





2 turnout decoder



Simple decoder for 2 turnouts with the 12F629 and fixed pulse time of 0.5s. To set a new address, press the button and move the turnout (odd address) you want as first turnout, the second will adopt the following address (even)

Schematics, program and the PCB can be downloaded here, if you want to know how to make the PCB or identify the components can read one of these tutorials.





Peripheals DCC



Salus designed these accessory decodersthat can be chained:

DEC-TRN Accessory decoder with transistor for big loads
DEC-AJT Accessory decoder with variable output voltage
DEC-RLE Decoder for 4 relays
DEC-SRV Decoder for 8 servos
DEC-MTR Master board to chain the modules

The design of the decoders you have here. HEX files to program the PIC can be downloaded here.





MOT-VREG



Adapters for accessory decoder outputs:

MOT Adapter for slow motion motor type Lemaco, Tillig, Conrad... up to 1A
VREG Output voltage regulated for accessories, semaphores... from 4V to 12V and 1A

It can be joined to control a motor and its speed. The design of the adapters you have here.