Voltimeter?

[zx81]

Hi

I have a signal between 0~24V and I want to convert it to digital (8 bits is enough) and send it to a PC (RS-232).This is all I need, I can use a Max232 or Max233 for the serial data, but any suggestion about a PIC model to make the conversion?

Regards

[ErnieM]

Literally most any PIC you pick will do. I search MChip's site for the flash units with 2 or more A2D's (the lowest count is will search for) and got back 166 of 186 hits. Even the lowly PIC10F220 (the tiny 6 pin SOT device) has flash memory and A2D

Microchip search page:
http://www.microchip.com/ParamChartSearch/params.aspx?branchID=1005&mid=10&lang=en&pageId=74

Just keep in mind the A2D converted can only range up to it's reference voltage (which is fixed to be VCC in the 10F220), so you'll need a voltage divider to being your 24V down to the range the PIC can read. That divider is also a nice place to add some overvoltage protection too.

[sammy]

Hi
take a look at the links i have pasted. they are great articles on how to use the ADC on small 8 pin pics.

http://www.rentron.com/four-channel-ad.htm
http://www.rentron.com/PIC12C67XAD.htm
http://www.rentron.com/PIC12C67X.htm
http://www.rentron.com/PICX2.htm

Micorhip makes the 12f675 which is the pic of choice if you want flash memory.

good luck

sam

[Acetronics2]

This link too ...

http://www.melabs.com/resources/samples/submitted/12F675_Voltage_Monitor.bas

Alain