PWM/HPWM Stepper Motor Controller

[DavyJones]

Normally I would design and build everything necessary to perform the tasks I need to with a PIC. In this case though to speed up development of my project I decided to use the stepper motor controller and relay module I am using to speed things up. The PIC is still doing all the work. I am working on a conveyer belt system that will move parts under a sprayer to get coated with a substance. I am controlling a solenoid to turn air on and off and a second solenoid to control dispensing the liquid, in this case for testing it is water. One thing I noticed since the nozzle is gravity fed and upside down as seen in my video, the gravity feed will produce a stream of water when the air is not engaged basically a constant drip so controlling the liquid flow (on and off) eliminates the drip. I did find no drip nozzles where I would only need to control the air flow but at $400 a pop that was not going to happen. The ones I am using are $20. My video is a mock up model for testing. I plan on adding a small conveyer pulley today and also control the stepper motor. If that succeeds I plan on moving to the next phase and build the working frame. I plan on using the extruded aluminum like many 3D printers use for frames.
If you or anyone else is interested in my progress as I move through this project I can keep posting the little videos I make.
Thanks for your help so far.
David
The air and liquid are not coming on simultaneously. The air valve is open first then 100ms seconds later I open the solenoid for the liquid. After 500ms of them both being on I turn them both off simultaneously then pause for 2 seconds to start the cycle again. This is producing almost virtually no drippage from the valve but I have on occasion seen a build up and a rogue drip is produced. I will mess with the timing to see if I can totally eliminate that or a tiny drip once in a while is not going to be bad since the part will have moved past the nozzle by that time.