Although we need to stress test it but I’d like to share the progress on the seeder conversions. Maybe we get more insight.
Motor
The center of the system is around a a ~250W wheelchair motor sourced from AliExpress.
Make sure it’s 75RPM! https://www.aliexpress.com/item/1005009030847143.html
Controlled by a Kamami motor driver. Which is like cytron but has a few key differences:
Screws to connect wires. Soft start (although I had this almost at fully off).
Power comes from a high-power step-up converter; it’s critical to check and set the output voltage before connecting anything. We’ve seen units set as high as 70–80V.
For feedback we use a 360 PPR encoder, which required an external pull-up resistor;
but there’s NPN / PNP so maybe its not needed for all of them.
Work switch I think best to use something like these: https://www.aliexpress.com/item/1005005715655894.html
Power connection I think this is the only seller who has a proper cable gland:
David has added the Bin level sensor detection so those could be connected as well.
I was short on inputs on my board so ended up using these optocouplers: https://www.aliexpress.com/item/4000121424232.html
The nice thing about them is you can connect the sensors like this:
5V / 12V → sensor → Opto IN (which will go through the coupler then a resistor and a LED) so if the LED is on you have signal 
the other end could be connected to any pin with input_pullup
Maybe and external trigger button could be also added for the very long term solution to start / stop the calibration from the seeder itself? But I think we’re already off to a good start.
