A weblog focused on interesting circuits, ideas, schematics and other information about microelectronics and microcontrollers.
E-books
Disclaimer
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.
PIC touch keypad
28. September 2007 - 13:50 — admin
If you need some kind of little bit excentric, unusual and good-looking touchpad, check the Luhan Monat's site 
for the PIC touchpad .
Luhan says:
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.
Mostly, this is just an example of how to make your own control panels. The system can be extended to more inputs depending on how many your micro has. This design provides a telephone style layout and is programmed to send out values in 9600 baud ascii.