IR DIY motorized lens-lift

I`m refurbishing my HT-room, and want to do a CIH-setup. I`m moving the amps, sources and projector to the room behind the back wall. I will be using an A-lens, and have been thinking of making a lift for the lens that can be built into the back wall. At first I thought of making a slide, using the inside of a flat bed scanner. I tried this, and I think it would have worked, except that the lens would block the ventilation openings of the projector. So to avoid this I made a lift instead of a slide. The scanner stepper motor didn`t have much power, and was not suitable for a lift. Might have worked with a reduction gear, and balancing out the weigth of the lens.

So I used a DC-gear motor instead. The motor is powered from a H-bridge. The H-bridge is controlled from a micro-controller, which get input from IR and an upper and lower position switch. If a switch is reached, the micro controller stops the motion, and stores the status in eeprom. So the status is known, even after a power cycle.

I uploaded a short video here to show it in action

Gunnar

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The electronics consist of three small boards. I did the powersupply/trigger board and the microcontroller board myself. I got the H-bridge from eBay for $5 INCLUDING shipping! This is less than I would pay for the 298H ship itself locally.
The box is just some scrap metal that I cut into a suitable size, and a little welding to keep it together.. The rest of the lift consist of a few pieces of scrap wood, and two drawer slides. I got the gear motor from eBay. Paid about $10. The microcontroller board has a demodulating IR-chip. The microcontroller decodes IR-signals from Sony TV-remotes directly. I used two codes, one for UP and one for DOWN. The microcontroller can decode all 127 Sony TV-codes. I will use some of these codes for the screen masking system.

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