Air assist

Machine: k40 custums build

Board: c3d mini

Firmware: _Smoothie

Problem/ Question: _ i want to buy and air solenoid but am not sure what current and voltage the c3d mini can output from the pins.
Help please thanks edgar

Hi Edgar,

It would depend on the specs of the device that you intend to connect and use. When searching the forum for “mini air”, the first several results show topics about what other people have done:

Please let us know exactly which air solenoid you had in mind, so we can better assist you with specifics of if that item is compatible, where, and how to hook it up.

Hi thanks, that why i asked for current and voltagev from the output of c3dmini.
So that way i know what to look for.
But anyways i have a 12v 500ma is it ok to use on the fets?

Hi Edgar,

Thank you for providing more details. The reason we ask for device specifications is to ensure it will be supported by the board.

If the board is being powered by 24v, then 12v is not available on the controller, so you would use a 24v solenoid for simplicity.

Thanks, but i do have a 24 v supply on the board, but isnt there a voltage in for the fet on cohesion mini?
I think i saw that there is a voltage in next to the fets and i though i could power then externally with other power source like 5v ex.

Hi Edgar,

The 5v available from the board itself, like the top 2 small FETs, is a very small amount.

We recommend using the FET2 (P2.7) on the bottom of the board, as it is larger and will provide whatever voltage you feed into the input terminal on the left side, like 12v from a separate power supply. You should install a flyback diode to protect from voltage spikes and ensure board stability with an inductive load, such as a solenoid. FET1 (P2.5) is used to control your laser, so do not use that one.


In the config file on your SD card, check the options for fan control, as seen below. Enable the fan (set to true). LightBurn uses M106 and M107 commands to enable and disable when the Air Assist feature is used in the Cut Settings Editor on the layer. The default fan pin number is 2.6. Update this to the pin number you connect to.

## Switch module for fan control                                  true                        M106            #                       M107            #                              2.7             #

Please refer to our Air Assist documentation for general setup information.

hi thanks for support.
so i can feed 12v from a power supply to the mosfet IN and then connect this 12v air solenoid direct to the fet2 .

Hi Edgar,

Yes, you could do that.

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