By request, just a quick thread about my new (touch sensitive) heated seat controller. Not too many details, but some photos at least...
I've been planning this for quite some time and had designed the circuit and written the microcontroller software last year. But it took me a long while to get around to raise the energy to design and make the actual buttons.
The controller is fairly simple, it just uses a couple of solid-state relays, one each side, and based on the number of presses, selects one of three heat levels (plus off). It adjusts the heat by just turning the power to the heating elements on and off at different duty-cycles. Simple really. There is a red and blue ganged LED that signals the level selected - red=high, purple=medium and blue=low.
So on to the photos! This first shows the top and bottom of my home-etched circuit board. The little surface-mount chip on the bottom is the touch sensor chip, the chip on the top (middle) is the Atmel AVR microcontroller and the two black squares off to the sides are the solid-state relays:
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This shows the heavy sheet of aluminium that I used for the relay heat sink, mounted to the top of the A/C controller - probably overkill since I found the relays barely got warm:
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Then these are the 'innards' of the switch buttons. At the back is a PCB that supports the backlight and signal LEDs, which is in turn glued to the touch-sensor PCB, in turn glued to the front lens. The lens was cut out of sheet acrylic, shaped and polished. And the icon made from laser-printed transparency sheet.
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The switch PCB assemblies (above) are inserted into the barrels which are screwed into the bottom of the A/C controller. Those barrels are (ahem) made from the hollowed-out top caps of two fingernail polish bottles
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Then this shows everything put together and mounted back on the Boomerang...
[attach=5]
And finally, the finished article from the front:
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