Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: Lubby on March 09, 2015, 10:09:00 PM
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I'm adapting my CNC for an art project - a video camera moving through a model set. It leads to yet another technical issue. I need to work out a way to create a dimmer for some lights, or control AC current. I think there's likely various ways to do this. I'd appreciate any feedback some of you might have.
A simple on/off would be quite easy through an output relay. The thing is that I want to be able to dim the light or control the intensity of it.
I could think of two possibilities:
1. With the machine as it currently is I'm no longer using a spindle. I'm wondering if I could use the VFD of the spindle to control a circuit board. This way I could simply include the intensity of the light within the G code ( or S Code) by increasing or decreasing the 'speed' of the spindle. Could this work? Any suggestions on a board that could work with this or what type of hardware would be needed?
2. Another consideration was to configure things for a servo spindle. I haven't done this before but I believe I can control the PWM rate this way. I could use the PWM to run a circuit board and control the lights.
I suppose a third option would be to use LEDs which are a bit easier to control digitally but it would still require some sort of VFD or PWM control I'd think... Unless I could use a stepper signal sent to an arduino which would then run a circuit board. This way I could just run the light's intensity like I would an axis using steps.
I'm sure this is outside the typical spectrum but I appreciate any feedback and hope this it might be informative to others in regards to the possibilities available in interfacing between Mach and the physical world.
Thanks
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Check out SSR's (Solid State Relays) - many types are 'opto-isolated', require less than 10mA drive current and can be driven directly from the Mach3 PWM signal (spindle control) and will switch a/c mains voltages proportionally with the PWM waveform. As they switch at the 'zero crossing point' of the mains a/c there is little or no EMI noise produced by their operation and this may offer a solution.
Tweakie.
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Thanks Tweakie.
I did do a test with an SSR and PWM fade running off an Arduino. There's problems with the AC wave and the digital pulse. It fades but it's quite choppy. I think this could likely be solved through a circuit board of some type. I'm just not sure which.
But good to know I might be able to do this through the PWM spindle control.
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Possibly a small motorized aperture ... or filter element ? Infinitely variable by motor position ?
Russ
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... at the light source of course, not at the camera. The filters could be colored to give additional effects.
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I found a PWM AC dimmer circuit board online ( https://www.tindie.com/products/thewp122/ac-60hz50hz-phase-controller-dimmer-board-arduino-compatible-2/ ) and I'll use the PWM spindle control to operate it.
Thanks for the feedback.
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Hook a SMALL stepper to a stock dimmer switch. Use an axis to control.
Easy Peasy, (;-) TP
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Hook a SMALL stepper to a stock dimmer switch. Use an axis to control.
Now THAT'S my kind of thinking right there, I luv it!
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Hook a SMALL stepper to a stock dimmer switch. Use an axis to control.
Easy Peasy, (;-) TP
Hear, hear! What a great idea. It's like an extra set of hands. Nice one.