DCC Layout Decoder v0.8.9 Purpose ------- The DCC Layout Decoder is a flexible accessory decoder for turnouts, signals, building lights and other devices that need to be switched on and off. Unlike many traditional and often more expensive accessory decoders, it is easily configured using a normal web browser. System concept -------------- The system consists of one DCC Basic Module with ESP32, OLED display and DCC input. Up to four DCC Layout Modules can be connected to the Basic Module. Each DCC Layout Module provides 8 physical outputs: - 1 module = 8 outputs = up to 4 turnout/signal drives - 2 modules = 16 outputs = up to 8 turnout/signal drives - 3 modules = 24 outputs = up to 12 turnout/signal drives - 4 modules = 32 outputs = up to 16 turnout/signal drives Momentary outputs - K83 ----------------------- Momentary (K83) is intended for turnouts, semaphore signals and other solenoid accessories. One DCC address controls two physical outputs (Green / Red), and the switching time can be configured in the web interface. Permanent outputs - K84 ----------------------- Permanent (K84) outputs can be configured individually as Contact or Light. Contact Normal ON/OFF operation for accessories that should remain switched on or off. Light Adjustable brightness and a choice of lighting effects: - Normal - Fade - Blink - Slow Blink - Flicker - Beacon Momentary and Permanent outputs can be freely combined across the connected Layout Modules. DCC addressing -------------- The DCC start address is selected in the web configuration. Addresses are assigned automatically and sequentially according to the selected K83/K84 configuration. K83 uses one DCC address for a pair of physical outputs. K84 uses one DCC address for each physical output. Web configuration ----------------- Configuration is performed through the ESP32 web interface. The number of Layout Modules, DCC start address, output type, switching time, brightness and lighting effects can all be configured from a normal browser. This avoids the often complicated programming procedures required by many traditional accessory decoders. Output test ----------- A dedicated Test page makes it possible to operate every configured output directly from the browser. Test commands are sent asynchronously, so the complete page does not reload after every operation. This makes testing fast and keeps the page at the current position while working with many outputs. Power supply ------------ DCC Basic Module: 5 V DC DCC Layout Module(s): 12-18 V DC accessory supply 18 V DC has been successfully tested with Märklin turnout drives, a semaphore signal and LED lighting. The ULN2803A DCC Layout Module described here is a DC output module. Do not connect AC to its accessory supply input. Important --------- Ordinary solenoid turnout motors must be configured as Momentary (K83). Do not configure a normal turnout coil as Permanent (K84). This can leave the coil continuously energized and may overheat or damage the turnout motor. Hardware -------- Each DCC Layout Module uses: - 1 x SN74HC595N 8-bit shift register - 1 x ULN2803A 8-channel Darlington transistor driver - 1 x 1000 uF / 25 V electrolytic capacitor - 2 x 100 nF ceramic capacitors - 1 x 10 kohm resistor - IC sockets and screw terminals/connectors See the separate Hardware documentation for the complete component list, connections and wiring diagram. Test status ----------- Version 0.8.9 has been tested with three connected DCC Layout Modules. The test setup included: - 3 turnout drives - 1 semaphore signal - 8 LEDs - different brightness levels - Normal, Fade, Blink, Slow Blink, Flicker and Beacon effects Operation from Win-Digipet 2025, including simultaneous switching of multiple accessories, has been tested successfully. Project UNION ------------- DCC Layout Decoder Software version: v0.8.9 Developer: Jens Krogsgaard