ZAF Plus Electronics
The electronics are probably the most technical part of ZAF+ construction. There is nothing overly complex, but it does require carefull planning and a lot of diligent soldering to connect the different electrical components. We therefore advice that you plan ahead. The electronics are comprised of four different components:
- A Raspberry Pi 3 B+ to run the software and control the electronics.
- Two Arduino Megas (Arduino 2560 R3) microcontrollers for the digital devices.
- Several motor controllers to control the various pumps.
- 16 Relay Module interface board to drive current and control the valves.
To summarize the wiring: the Raspberry Pi is connected directly to one Arduino Mega using a USB cable. The two Arduinos are daisy-chained via a serial connection (the whole design can be extended by daisy-chaining more arduinos). The Arduinos are connected the motor controllers through digital pins (PWM). The Arduinos control the opening of each individual valve through the 16 relay module. A 12V power supply (at least 10A best 20A) provides power to the electronics, except for the Raspberry Pi and the two Arduino Megas powered by the Raspberry Pi 5V.
The following figure summarises ZAF+ electronic connections:
