Hey! I’m very new to this but I wanted to see how to use an arduino to push in an airbrush trigger for a specified amount of time.
I know I’d have to make a setup to hold any device near the trigger and that’s not the problem I’m simply wondering what’s the best way to do it.
I am thinking about using either a solenoid or a servo motor. My fear with the servo motor is if it can apply enough pressure (and I don’t understand the code aspect) and with the solenoid I fear if it is running too long it will overheat.
I’m imagining a maximum run time as around 30 sec to a minute perhaps continuously. But this cycle of 30sec pause 30sec spray could go on for 5 or 10 min.
How much force does it take to push the trigger(operation lever). Can you measure it with a push/pull spring scale? Or put a known weight on it?
I would think that a servo rotating a cam through 90 degrees would work fine to push the trigger but you will need to know the force required to select the servo.
I'm not sure a servo will give you the level of precision that airbrushing something well demands. I don't know your application (are we painting miniature figurines or walls?) but I would try to control the mechanism before the trigger. Instead of adding onto the trigger, would it be reasonable to replace the trigger altogether?
EDIT: after reading @cattledog reply, I started thinking about it a bit more. That could work I think, like an old-style mechanical (hobby grade) RC speed controller.
Actually a solenoid has equal forces on the piston and on the body of the solenoid. To make the thing do movement, the body of the solenoid is mounted in/on some structure, usually metal. That structure provides heat sinking for the solenoid body. So much depends on the heat created by whatever solenoid you choose.
The operation lever (trigger) moves forward/backward to move the pin backwards, out of and opening the nozzle or forward, into and plugging the nozzle.
Luckily for my project I only need something to push the trigger in. Even though it’s a dual action airbrush I don’t need to control the needle and will just be using one “fixed” setting.
I agree that’s the biggest issue. I want to say 5N of force seems to be good enough. I haven’t been able to measure it yet though sadly as I’m trying to design this for a friend and haven’t had access to the airbrush
Wait can you elaborate on this with maybe an example? I understand using a lever for better leverage and the longer the arm the greater the conversion of downward force to the force applied but do you mind explaining how I’d do this with a solenoid?
Examine the trigger of your spray gun. The trigger is a lever, it's attached to a pivot at one end, the attachment to the valve is part way up the trigger. When you squeeze your finger travels further than the attachment point, which in turn travels further than the valve.
