Micro DCC control unit

The DCC micro power station project now offers several DIY assembly solutions. This project, which is still evolving, offers you turnkey solutions for building and controlling your own digital rail network.

The different solutions

Maturity : 100%

The ideal way to get started by building your own DCC control unit. This assembly, combined with JMRI software, enables you to control several locomotives simultaneously. The simple construction of this control unit enables a complete understanding of the entire process, from the command sent to the generation of the DCC signal on the rails.

Maturity : 80%

Several add-on modules (current measurement, control via Bluetooth or WIFI network, etc.) can be connected to the microcontroller, which offers new functionalities.

Combined with the BLE joystick module, it becomes self-sufficient, controlling up to four motors stored in EEPROM.

Technical choices

The only constraint initially set in the specifications was to produce the smallest, simplest DCC unit possible, with all the functions of a large one.

Here are the choices made during the design of these assemblies, and the arguments that led to this solution:

  • A single traction track: the duration of use of a programming track is very low compared to the duration of operation. It's a waste of resources to have a power circuit with current measurement that's practically never used. It's better to be able to select the operating mode, so that you can still set the parameters for your locomotives.
  • Do not use a commercially available power module that has already been assembled: commercial L298N-based modules contain a lot of bulky components that are also unnecessary for this project: 5 V power supply, terminal blocks, smoothing capacitors, jumpers, etc.
  • Do not use MAX47X-based modules to measure current consumption: in addition to being prone to failure, these small commercial modules have a significant impact on the circuit, due to the high value of the resistor used for measurement. Current consumption will be monitored using an op-amp-based circuit.
  • Use an Arduino Nano board to generate the DCC signal: to save space for the microcontroller, the DCC++ program will have to be adapted for use with the Nano. This operation (already carried out by a modeler on the Locoduino website) simply involves replacing the Arduino Uno references in the program with those of the Nano.
  • To be able to control a number of motors without having to type in codes to access functions, and to avoid using a keyboard as much as possible.