Middlesex County, Ontario | I didn't decide on this either.
One approach is to wire all valve control to the arduino only. The only way to move the valve is through the arduino. You then wire in your existing buttons or toggle switches or joystick to the arduino as inputs. The arduino monitors those inputs and if it senses that you moved a switch, the arduino automatically switches to manual mode and does what you tell is to with the switches. If your current switch box has small switches, it probably has a pcb and you would need to cut traces and add wires. You would need circuitry capable of driving solenoids.
Another approach is to intercept the actual wires at the valve. Add in switching relays. One position is solenoids connected to arduino, the other position is solenoids connected to existing sprayer controls. You would need circuitry capable of driving solenoids. You could still monitor the old wires for signals to automatically switch back to manual mode. This approach does not require modifying any existing wiring. You could intercept at the solenoid plugs with a T harness. It could potentially harm the existing solenoid drivers if equipped, they don't like to be disconnected while the coil is active.
Another approach if you have a switch box with small switches (meaning there are solenoid drivers somewhere in the system) is to intercept the manual switches, and use the arduino outputs to mimic those switches. This means you do not require circuitry capable of driving a solenoid, you use the existing solenoid drivers.
Another approach is to tap into the CAN or whatever communication protocol used on your sprayer and command the booms to move that way. I think my Hardi is capable of this, as I believe there is an auto height system available that functions this way. I've gathered some documentation on the communication protocol but I'm not willing to invest the time or risk my system to go this route. With a CAN system I would be willing to experiment, especially J1939. I've worked on engineering for concrete mixers where all mixer controls were over a J1939 CAN connection and it worked fantastic.
I think the second approach would be the way to go as it does not require modifying the existing system, can be unplugged and removed/bypassed easily, and it is the most universal. If we were to all collaborate on a universal open source system, that second method would get my vote. |
DIY auto boom height control
