I have the control board for my DIY motorized standing desk wired up, and ran a test of the board controlling 3 linear actuators at the same time. I knew the wiring and software worked for 1 actuator, but this was the first time that I connected more than one actuator up. The desk will be lifted by 3 actuators so I needed to be sure this worked.
Here it is, worked on the first try and nothing caught on fire!
One thing of note – I had initially planned to control each actuator independently from the Raspberry Pi, with each relay signaled from a different GPIO pin.
However, in the midst of wiring the control board up I realized that it was possible that a software bug, crash, or other unforeseen scenario on the Pi could theoretically result in actuators moving in different directions, and that would be a Very Bad Thing (images of broken desks, shattered monitors, and crushed babies come to mind).
So they are all wired now on 2 GPIO pins (one for the “A” relays, and one for the “B” relays).
So now the leg apparatus’ are built, and the control board is working. Next step: put it all together!