Machine Control Board - USB

I’ve made the schematic for the USB Machine Board. Quite simple to assemble point to point even.

See corrected schematic below



Have you looked at the SK21 board? It looks pretty similiar and would just need a different ino. It’ll use USB regular Nano or the Nano33 IOT

Hi Brian, looks good. Couple questions.
Do I need the LM2596 or could I power it off the 5volts that is available on the autosteer PCB board, or is there too much draw?
Is the nano being powered by the USB?
On the relay module there is a vcc jumper, do you know what that is for?
Thanks for the wiring diagram, I just have a 4 channel now was just going to do left and right sectional, then end row lift so hoping 4 channels will do it

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I would just add another LM2596 and then you are good. Power the nano with the usb then since all the real power needs will be powered by the supply, the nano will use almost nothing.

I’m not sure what the vcc jumper is for exactly on your particular board for sure, they are all a little different and quirky, but here is a good description that might match yours. One way is fully isolated, the other not. Adjust the schematic accordingly.

And another good one here:

The LM2596 is on its way! Changed back to 8 channel relay board seeing I had it in a bag anyway. My WAS is on right side of pic, it’s a honeywell magnetic so we well see how well it works on pivot of 4wd

Thanks Brian

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The one thing that isn’t in the code is if the relays are inverted, like 1 is off and 0 is on. Can add the code as req’d to make that work “upside down” if needed

you can use the all in one section control code. In the setup zone of the code you can set SectRelaysON = 0 so they spray on low. If You don’t use switches, set everything about them to false

I heard already people asking that, are coming from Cerea

You can also just run the relays with VCC and signal and use the optoisolator built in for isolation rather then pulling signal low and common ground.

This is the proper way to use those relay boards

Would one of the power supplies need to be an isolated power supply such as:

No, with proper grounding, the current draw from the relays is not seen in the autosteer board ground if used as opto input type relay

The new updated schematic. Now a low turns on the relay, and its isolated, best of both worlds. You can still use the +5 from the nano if you only have a couple of relays, just connect Nano +5 to JD-Vcc.


Is it possable to use an nano 33 IOT in place of a plain NANO. When i try to upload machine usb to it i get this message

Arduino: 1.8.12 (Windows 10), Board: “Arduino NANO 33 IoT”

Machine_USB:9:12: fatal error: EEPROM.h: No such file or directory

#include <EEPROM.h>


compilation terminated.

exit status 1
EEPROM.h: No such file or directory

This report would have more information with
“Show verbose output during compilation”
option enabled in File → Preferences.

The Nano33 doesn’t have eeprom. So it won’t work with an ino for the Nano that uses eeprom.

Ok their is no quick change in program to make it work?

There is no quick change. There is a work around. Just looking for it now.

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I believe you can use this:

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I have a rewrite for Nano33Iot and I’m using it on my sprayer:
It works on ESP32 and Nano33iot.


  • switches
  • relays or documentation only
  • 2 independent WiFi networks
  • Webinterface

based on the WEder circuit, but adjustable pinout

Would this be set up to work with machine control? I need 2 relays for hydraulic lift and 2 for section control?

The code above is for section control. If you need hydraulic lift, it might be supported by the autosteer code, as well as the section control as output only.