Raspberry Pi Pico Powered Dosing System Keeps Fish Happy

Whether you have expensive tropical fish, delicate reefs, or humble goldfish. You need to keep your tank clean for your aquatic pets. And this Raspberry Pi Pico-powered dosing pump is just the thing. Created by yojoebosolo (Joe Stiff), this $18 (£14) tiny pump project provides microdoses of a chemical that maintains a fish tank. 

The pump system is a peristaltic pump that uses mechanical manipulation to move the liquid through a tube. This pump system is commonly used in medical and scientific applications where precision and hygiene are key. The tube can be easily replaced as no liquids go through the pump. They are massaged through the tube. And they can be swapped for a different liquid. Yojoebosolo uses it to micro-dose various chemicals into a fish tank.

Powering the project is a Raspberry Pi Pico. Based on the low price in the Bill of Materials, we see that it was the Pico, not the Raspberry Pi Pico W. Details are dotted across the rather lengthy comments section. There we can see that a two-channel relay controls the pumps. We can only see one input, a micro USB port, on the back of the 3D-printed case. The relay is directly connected to the Pico’s 5V supply, and a GPIO pin on the Pico controls the open/closed state of the relay contacts.

The 3D-printed case is simple but beautifully made. The front of the case holds the pumps, secured using machine screws. Looking inside the case, thanks to a downloadable 3D model, we can see where the Raspberry Pi Pico can be secured (left) and where the two channel relays are housed (right).

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