rotating a dimmer switch - board/motor choice?

Any other Phidget projects you've done not related to the above subjects
jeraux
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rotating a dimmer switch - board/motor choice?

Postby jeraux » Wed Oct 12, 2011 8:01 pm

For the life of me I can't find a automated dimmer switch that I can control via usb except for automated home devices that start over $50/pc for each peace!! Too Much, and the learning opportunities are limited by having to use proprietary software.

So, I would like to connect the shaft of a dimmer switch to the shaft of a motor and use it to control stage lighting - forward to brighten, reverse to dim. There is also an opportunity to motorize the lights for tilting up and down, hopefully the same type of motor could be used for that application. I need to be able to rotate the dimmers a specified number of 'steps' forward and backward (so i may need to fully rotate depending upon the dimmer switch limits). I also need to determine the current position so the next scene does not have to start with the dimmers off each time. The tilting application will require similar functionality without the full rotation.

So which is it - stepper or servo?

This is my first venture into interfacing the computer with the physical world, all my experience has been database/web (vb/asp/sql) related...I'm looking forward to the challenge and hopefully I'm not in over my head.

erik
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Re: rotating a dimmer switch - board/motor choice?

Postby erik » Thu Oct 13, 2011 9:18 am

Most servos can only rotate approximately 180 degrees, and I assume that the dimmers are probably closer to 300 degrees. It might be enough that the lights you control only need to go up to 60%, depending on the overall brightness or the lights, or you can have the range set anywhere, such as 10% to 70%, 20% to 80%, etc. You could also try looking for servos that have a greater rotation range (such as the GWS S-125), and there are also some websites that describe how to mod a half-revolution servo to enable it to go for more degrees.

Using the steppers will give you the ability to rotate the full range of your dimmers (and then some). However, steppers "forget" their CurrentPosition if the controller is unplugged or turned off. So you will need to incorporate the last known position into your program or write some calibration routine at start up to determine where the stepper is set to.

I think that the servos will probably be the easiest way to have this all set up.

Alternatively, there are some stage lighting systems that can be controlled by a 0 to 10V input. If your system can be controlled in this way, take a look at the 1002 PhidgetAnalog which can be programmed for -10 to +10V.

jeraux
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Re: rotating a dimmer switch - board/motor choice?

Postby jeraux » Fri Oct 14, 2011 3:51 am

The full 360 servo seems like just the thing. I'll no doubt be back for more advice soon enough - thanks.

jeraux
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Re: rotating a dimmer switch - board/motor choice?

Postby jeraux » Sat Oct 22, 2011 3:50 am

Could the servo/stepper controllers control an RGB led light...? I've provided a link to a product that is similar to others i've seen all be it a bit extreme, most have forward voltages below 12v.

http://www.ebay.ca/itm/30-Watt-High-Power-RGB-Full-Color-Rainbow-LED-Light-DIY-/360396470423?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item53e94db897


If so, could I get an example of one...i've read specs on the ones here and at pololu and there are lots available with example code and sample applications.

I will greatly appreciate any help - thanks in advance!!


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