Using RCTIME to create a crude touch sensor
Morrolan
Posts: 98
Hi All,
Today I attended a seminar held by Freescale Semiconductor aimed at ultra-low power microcontrollers (3uA for the MCU and also running/powering an LCD!) and one interesting thing I noticed is that we were using touch sensors but without any hardware - we wer simply pressing an area of the PCB under green solder mask. It turns out all of the touch sensor controls are done by the MCU in code.
This got me thinking - if you used RCTIME to do the same thing, would the added resistance of a human finger be enough to enable me to discern whether or not the sensor had been pressed?
Has anyone tried this kind of thing before?
Many Thanks,
Morrolan
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Flying is simple. You just throw yourself at the ground and miss.
"I think computer viruses should count as life. I think it says something about human nature that the only form of life we have created so far is purely destructive. We've created life in our own image."
Stephen Hawking
Today I attended a seminar held by Freescale Semiconductor aimed at ultra-low power microcontrollers (3uA for the MCU and also running/powering an LCD!) and one interesting thing I noticed is that we were using touch sensors but without any hardware - we wer simply pressing an area of the PCB under green solder mask. It turns out all of the touch sensor controls are done by the MCU in code.
This got me thinking - if you used RCTIME to do the same thing, would the added resistance of a human finger be enough to enable me to discern whether or not the sensor had been pressed?
Has anyone tried this kind of thing before?
Many Thanks,
Morrolan
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Flying is simple. You just throw yourself at the ground and miss.
"I think computer viruses should count as life. I think it says something about human nature that the only form of life we have created so far is purely destructive. We've created life in our own image."
Stephen Hawking
Comments
Set it up with say .01 uf and a 10K resistor. Arrange the circuit so your finger is applied in parallel with the 10K resistor. Watch the results with DEBUG. With no finger applied, the RCTIME value will be relatively steady. When the finger is in parallel, the RCTIME will vary.
Cheers,
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Tom Sisk
http://www.siskconsult.com
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