I recently faced a similar problem when I hacked the settings panel on a hot tub. The button technology in this case is based on potted piezo sensors and likewise did not respond to ohm-meter probing. I was fortunate in that the manufacturer provided a "parallel" connector (RJ-45 in this case) on the controller board. This allowed me to match pins to switches by measuring voltages with the unit powered up. The trick was finding out which pin carried VCC (5V in this case). It turned out that the switch outputs easily drive the inputs to an AVR and I am able to control them with software. The display in my case, uses 2 of the wires (clock and data) for a modified SPI interface (7bit bursts providing for each 7-segment pattern). An oscilloscope helps here.
From: Russell Senior <[email protected]> To: "A discussion list for dorkbot-pdx (portland, or)" <[email protected]> Sent: Saturday, May 2, 2015 12:05 AM Subject: Re: [dorkbotpdx-blabber] Gas range control panel >>>>> "Kenny" == Kenny <[email protected]> writes: Kenny> If the buttons deflect when pressing them, it is probably a Kenny> diaphragm key matrix, but you would have likely found that with Kenny> your meter. Kenny> http://pcbheaven.com/wikipages/How_Key_Matrices_Works/ Kenny> If there is a solid surface with no button deflection, then it is Kenny> probably a multi-electrode capacitive touch sensor with an Kenny> integrated controller and some simple bus connecting back to the Kenny> "computer". https://www.sparkfun.com/products/9695 Kenny> I assume this control panel is for the oven/clock and not the Kenny> range. A residential gas burner without a mechanical knob/valve Kenny> is pretty rare. The buttons don't seem to deflect (there are 24 labelled "buttons"), and yes, it's the oven-control/clock. I don't actually know what a range is. I meant "the box that gets hot with a surface on top with flames that shoot out." ;-) The top burners have mechanical knobs in front, as you guessed. I guess I should try busting out the soldering iron and see if I can interpose myself between the keypad/display and the computer and see if I can see what they are saying to each other. -- Russell Senior [email protected] _______________________________________________ dorkbotpdx-blabber mailing list [email protected] http://music.columbia.edu/mailman/listinfo/dorkbotpdx-blabber
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