In the previous tutorial, we learned together how to use solenoid actuators to move the turnouts in a digital model railway.
Sometimes those actuators don’t move correctly, due to the power supply not capable of providing enough current. It’s possible to solve this problem by adding a device called CDU (Capacitor Discharge Unit), which stores the current when the turnout is not moving and can provide it rapidly when the turnout has to move:
All the documentation needed to assembly this device is opensource and available in my Github repository.
The topic for today’s tutorial is instead the second family of actuators: dc motors (or point motors):
Those actuators has some advantages: they are “slow”, so the turnout moves more realisticly, they are quiet and they require less current.
To control them with Arduino, and therefore build a DCC accessory decoder, you need an H Bridge, like the one already used when we built together a DCC booster. One of the most common ICs to control small motors is without dubts the L293D, which I used to design the board presented in the tutorial:
(the documents for this board are also available in my Github repository)
Enjoy!