Check out this cool PIC Microcontroller Touch Keypad by Mondo Technology. I love the simplicity of button press detection. There are lots of industrial buttons that do this exact thing but they are very costly.
“This board layout was created using the SOIC version of a PIC16F627A without drawing the usual schematic first. Most of the part values are etched on the Layout. The SIP resistor packs I used are 10k ohm, some experimentation with this value may be useful.
The actual data from the touch sensors is quite erratic and requires some software processing. Basically you create a pulse for each of the ports and read the data with the instruction following the pulse signlal rise. Then read the ports the same way looking for a gap of 0.1 seconds with no data detected. This does the ‘debounce’. This results in fairly clean data capture from the sensors.”
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Cool idea but the chopper will be dirty after so much touching. And what if you are loaded with static electricity? The pic will die.
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Some 5.1 Volt zeners could prevent the static shock death. I would be interested to see what an industrial circuit looks like.
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Well i think in indurtries they use piezo keypad or a special thing which is a 3 layered stuff: between two layer there are microswitches.
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I’ll have to make one of those in the near future!