Build one with 12v peristaltic pumps and H Bridge motor driver. I used to use L298n but recently swapped to a board Adafruit makes which is a PCA9285 with two TB6612 which gives you 4 outputs per board. I also automate my dosing of nutes etc so I first lower the speed of the pump and then coding it for forward and reverse for TIME based calibration. I have also just ordered 8 x HX711 5kg load sensors as each pump has a pipe to a 2 litre glass mason jar. Below the jar is a 90mm PC fan with magnets attached which spin up before dosing and there is food safe magnets in the jars. So once these cheap £3.20ish scales arrive I don’t have to use just time, I can use a combination of weight and time. Having the scales also lets me know how much solution is in each one also.
This is all doable via Home Assistant and ESPHome and I decided to mount the pumps in my main control box. I cannot take credit for this design as it’s based on LEDGardener who was the boss of Home Assistant Hydroponic Automation. I just a changed a few things like using a more efficient motor drivers, only 2 wires to the ESP (i2c) and adding the scales.
I’m using a Gothen 12v G9XX (forgot the last two digits. Run the hole saw (I used a 3in reverse stop plastic cracking and also biting into the plastic as it can REALLY small at you if it’s a decent high torque drill!
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Slow and steady! These enclosures are not cheap (this was around £70 without the plastic grill inside.View attachment 5272102
Finished! Just wire to the motors to pumps and keep them tidy.
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ESP32-S3 in the middle with 4 motor channels each side sitting on feather triplet or whatever it’s called. When happy, il make my own PCB up using the same components plus the required resistors as il be embedding an ESP32 into my control PCB board:
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