Help with air assist board hookup

need help figuring out how to hookup air assist on my smoothie board. I attached some files to show what I’ve tried so far with no sucess.

when I send M106 from console it does not trigger my SS relay, which requires 3-32 VDC to trigger it. I tried changing pwm to digital yet its not triggering the relay. I assumed it would send 5v to the relay but apparently not ! not sure what I’m doing wrong, any help would be appreciated.

What are you driving with the solid state relay?

If you are driving the compressor or something you want on/off you probably don’t want a pwm signal. SSR’s switch on the zero voltage crossing, if it’s on and off, it can be an issue.

I have one on my machine for ventilation, but on mine, it’s wired to 24V then the Ruida controller completes the ground to enable it.

Does your Smoothie board output the 5v or does it sink the current?


thats just it I don’t know that much on this subject. my objective is just to get it to send 5 volts to ss relay

Do you have a voltmeter? That is by far the best way to tell… measure the output of the controller to see if it responds.

Do you know if it supplies or sinks current.?

I thought @berainlb has one of these and can probably better advise you as to what codes are being sent and the proper configuration of the SD card.

I don’t see anything directly that specifies air assist, although I know they do it with a smoothie.

The M104, from this link is

M104 	Set Extruder Temperature - S<temperature> 	M104 S190

Is this the right code related to the SD configuration?

Voltmeters on Amazon start at <$10… a good investment that you can use for many things …

Check out this thread and see if it helps…


@jkwilborn Note that I do not own this board.

In any case, agree with Jack on need for a voltmeter/multimeter. Trying to work through this without one would be needlessly difficult.

A few things that stick out to me:

  1. In the config file that you show you have both listed modules assigned to pin 2.4. Did you modify the config file this way?
  2. You list pin 2.5 as “Dedicated air assist pin” but don’t indicate how you attempted to enable it. I’d assume this would activate with M8.

I’d suggest measuring voltages at those pins at idle and then with those commands enabled to see if you get a voltage shift.

Sorry, though you had one of these… It’s always nice to have someone with experience on a specific kind of hard/software.

I guess I can’t keep track of them all…


1 Like

ok, been struggling with this for a while . I will try doing these measurements today. thanks

By the way, I took a look at LightBurn gcode for air-assist and it looks like it’s generating M106 for air on and M107 for air off.

once machine is powered up there is 1.2 vdc on pin 2.4 and ground, when I send M106 fromlightburn console it doesnt change. I have the switch set to true, pin 2.4 digital and not getting the min 3vdc needed to trigger relay

Have you tried pin 2.5? You may want to try M106 as well as M7 and M8.