Automatic Watering Pot Filling Device (Rain-O-Mat)

2026-02-13 - Edit: 
Upon request I added some more photographs and in the file section the Arduino Nano-Sketch. 
With the pictures, the code and some following information you should be able to rebuild this built.
For the valve I used a Schottky diod 60V/5A (SR560/SB560). This diod is the prevent current going backwards and estroy any electronics (e.g. MicroProcessor), when the valve ist shut off. The magnetic field may induce a not negegable current. But you need to get any informations how to use this diod. I assume to put it in between the power (+) and the magnetic spool, but you need to find that out. This project is 5 1/2 years ago. Meanwhile I moved further down the road.
The little display beside the OLED screen is only a Voltmeter which tells you how much juice still is available from the two LiIon 18650 batteries.
Function: You adjust the time for opening the valve by a potentiometer. Green button starts opening the valve for the duration of the adjusted time in seconds. 

Red button shuts it off. Yellow button is to open the valve as long as you press this button.

During summer watering flowerd etc. is a bit exhausting. When you need to observe the filling of a watering pot, it is even more driving you nuts. At least it drove ME nuts!

With the aid of my ideas, an Arduino Nano, several feet of filament and some solder I managed this project!

Print Settings

Printer: Prusa MK3s with MMU, Voron 0, Voron 2.4
Rafts: Doesn't Matter
Supports: Yes
Resolution: 0.2mm, 0.1mm
Infill: 15-40% depends on the part
Filament: Doesnt matter PETG, PLA, TPU

Notes:

TPU for the latch, this replaces any steel spring.
The latch I found on Thingiverse. Thanks to "kdtop3" who put the SCAD files on Thingiverse. I needed to do some modifications, but the base idea and base design was great!