µ[micro]electronics info

A weblog focused on interesting circuits, ideas, schematics and other information about microelectronics and microcontrollers.




Because I have not tested all electronic circuits mentioned on this pages, I cannot attest to their accuracy; therefore, I do not provide a warranty of any kind and cannot be held responsible in any manner.

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Touch sensors

Two touch sensors based on an ARM microcontroller.

The first one is the piece based on AT90S2313 with two sensing plates and two switches. Author (Pontus Frössander) says: "The basic idea is really simple. Make one pin output and another input. Connect a resistor between these pins. The resistor together with the human capacitance (about 100 pF) forms an RC network. The AVR set the output to low and then make a transition from 0V to +5V. 5 µs after this switch, the logic level at the input pin is sampled. If someone is touching the probe connected to the input pin, the capacitor (=human) will not be fully charged, and the input will be a digital 0 and vice versa."

Link: Touch sensor

The second one is ftom the well known ELM-CHAN pages. It implements the capacitive touch sensor (the same principle as the first one), but it provides 8 sensors and it's based on ATTiny2313.

Link: Simple touch sensor

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