Sunday, August 2, 2009
16F88 3-digit voltmeter
I wanted to make a simple 3 digit voltmeter for mounting inside a power supply for troubleshooting purposes. Scouting around the internet, I couldn't find anything complete enough to make a meter. So I decided to make my own using Pic Pro basic to program a 16F88 PIC. Micro Engineering Labs has a good tutorial on how to interface a 4 digit led display to a pic. The tutorial was helpful enough that I was able to fashion a circuit and program into a usable meter. Then it dawned on me that the circuit could become an event counter by changing the input stage and program. The event counter uses a 16F628A or 16F88, since both pics have the same I/O pinout.
The circuit is also compatible with a frequency counter I found on the net. This circuit uses a 16F628. Use code "COUNTER3.HEX" for common anode display found at that site. This site got me started in making a multipurpose board.
Below I included links to my programs and schematic for anyone else to make there own. You can use the programs and circuit freely, just don't make money with it.
PBP Basic Program as 100V meter.
Hex file for 16F88 PIC
Schematic in PDF
PBP Basic Program as event counter.
Hex file for 16F628A
Hex file for 16F88