ConnivingPigeon's reef-pi build

ConnivingPigeon · Jul 22, 2023

Hi all!

I wanted to share my in-progress reef-pi build. I have a small fluval evo 13 gallon tank, so this is certainly overkill, but I enjoy the challenge. I currently have a very simple setup on a breadboard, with a Ph probe, temp sensor, float switch and a relay to turn on/off an ATO pump. I wanted to make something more permanent, and also learn some more about basic PCB designing, so I came up with the following PCB in KiCad.

It supports an Atlas Scientific Ph probe, 3 temp probes, 4 digital GPIOs, two 12v pump relays, and has some additional headers for extensibility -- I pull out two additional I2C headers and an SPI header for output, as well as some voltage pins so I can expand later if I want to.

I sent off the board to be printed, so hopefully in a few weeks I'll have more pics.

theatrus · Jul 22, 2023

Very nice - glad to see more custom boards showing up

Sral · Jul 29, 2023

very nice indeed !
I would recommend testing the 4.7k pull-up on the temperature sensors though. I think I have read on an official manufacturer document about stable OneWire buses that they recommend lower resistance when operating on 3.3V

theatrus · Jul 29, 2023

Sral said:
very nice indeed !
I would recommend testing the 4.7k pull-up on the temperature sensors though. I think I have read on an official manufacturer document about stable OneWire buses that they recommend lower resistance when operating on 3.3V

Also, you can generally power the sensors on 5V and use a 3.3V pull-up. Remember most of the sensors don't use real DS18B20 chips so behavior can be pretty puzzling and inconsistent