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
DCC2DMX	DMX lighting decoder
KDaktion	Action pushbutton decoder
PpP Decoders	Decoders for semaphores, turnouts, lighting.

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).

Take a look to Collaborations section the contributions to this design that you have sent me.

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

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:

Take a look to Collaborations section the contributions to this design that you have sent me.

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.

Take a look to Collaborations section the contributions to this design that you have sent me.

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

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.

Version of the ServoPoint with 4 positions for the PIC12F629, PIC12F675 and PIC12F683:

The ServoPoint 4p decoder is a DCC accessory decoder specially created to control a servo with 2, 3 or 4 positions and a relay independent or linked to the servo positions.

The decoder uses 3 consecutive accessory addresses. The first one moves the servo to positions A or B, the second one moves the servo to positions C or D. The last one changes the relay if it is independent of the servo positions or moves the servo to the position to the that the relay is linked so that it changes when the servo reaches the position.

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 or PIC12F675 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.

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.

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 program 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.

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.

The manual, program and the PCB can be downloaded here. When you program 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 PIC must be programmed with the corresponding HEX file before mounting it on the board.

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.

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

Adapters for accessory decoder outputs:

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

With the TT-F9152 decoder you can control the turntable manually and digitally, each really existing track can be accessed directly thanks to the indexing capacity. The bridge can be rotated to the next existing track with a single pass. It can also be rotated 180º with a single command.

It works in analog or digital (DCC or Motorola), being able to be controlled and programmed from the three buttons of the control panel or in digital with the commands Marklin 7686.

For the 48 track turntables Fleischmann 9152, 9152C, 6152, 6651C, Arnold 6381 and with the 24 tracks Roco 35900 and with little work in the Atlas N. You can find the design of this decoder here.

DCC2DMX - DMX lighting decoder

Many large models have ambient lighting with DMX modules that allows them to have the focus of attention at the right time in a particular scene or by combining several colours in lighting, the effect of sunrise and sunset to a light day or night ambient.

The DCC2DMX is a DCC decoder that has an output to control DMX lighting equipment. You control it as a DCC locomotive and the speed control regulates the intensity of the channel, you can directly control up to 28 channels with function keys, has 4 additional channels to provide automatic day/night lighting transition with the light function.

We can assign a different locomotive for each of the 32 channels, channels not assigned can continue to be controlled with the master locomotive and the corresponding function key. You can store and retrieve the current status of the lighting channels controlled by the master locomotive address, so you can have different preset lighting scenes.

If we use a long address for the locomotive master, you can enable a mode that besides the locomotive decoder has an accessory decoder with which to retrieve scenes or activate day / night transitions.

The DCC2DMX was used for the night/day illumination of the missing Scopic Miniatur Barcelona model railway

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.

KDaktion - Action pushbutton decoder

One of the things that attracts the attention of the railway models in addition to the trains themselves, are the scenes with animation or movement. So that the visitor can also interact on the model, you can distribute some buttons that press on them to start a certain animation or runs for a while.

KDaktion (from German Knopfdruckaktion: Action pushbutton) allows you to activate two digital outputs or servos for a while and with a programmable sequence so that you can make simple animations that give life to the model. You can also set a waiting time between two animations so that the movement of the public is favored during the visit of the model.

When the two-color green LED is illuminated, the button can be pressed to start the animation, when pressed, the green LED will turn off and the red LED will light indicating that the programmed sequences are being performed on the outputs that can be: move the Servo to a certain position, activate / deactivate the digital outputs, repeat actions a certain number of times or wait.

Once the sequences are finished, the red LED will flash during the programmed time during which the animation cannot be started, once the time has elapsed the green LED will illuminate. If the button is pressed while the LED is flashing in red, it will flash alternately in red and green indicating that the sequence will start again as soon as the timeout period expires.

It is very versatile since by mounting the appropriate components you can control two servos (to move an excavator like the one in the image), a servo and an output, two outputs, a servo and an input, or an output and an input

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.