(a) Schematic representation of ZAF’s three main modules with their key components. Basic electronic wiring is also shown. ZAF is designed to distribute the same food quantity to all (fish) tanks. (b) 3D visualization of the different ZAF modules: electronics, tubing, pumps, and food preparation. (c) Variation of the fish mean weight over 8 weeks during ZAF feeding (n = 7) versus manually-fed fish (n = 6). (d) Spawning success for ZAF fed fish versus a manually-fed fish (spawning evaluated at weeks 2 and 6). All bars indicate s.e.m.

ZAF+ main electronics components are a Raspberry Pi 3B+ to run the software and control the electronics, Arduino Megas Arduino 2560 microcontrollers for the digital devices, motor controllers to control the various pumps and 16 Relay Module interface board to drive current and control the valves. 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 to the motor controllers through digital pins. The Arduinos control the opening of each individual valve through the 16 relay module. A 12V power supply provides power to the electronics, except for the Raspberry Pi and the two Arduino Megas powered by the Raspberry Pi 5V.