voltage monitor

[samtheboxer]

Samtheboxer,

Dave has already sent you a link that explains what a voltage divider is and how to figure the correct values of resistors to use so I won't repeat his info.

Whether you use an ADC or comparator you will need to use a voltage divider to divide down the battery voltage into a range that is safe for the PIC.

I suggested using a comparator and interupt because it doesn't require clock cycles from the PIC unless the battery voltage has dropped below the pre set threshold. I was thinking that he just wanted some sort of failsafe that would shut things down if the battery voltage dropped to low but do other things in the mean time. I am using just such a feature on a project that I am working on now. After re reading the original post I see that what was really wanted was to circuit that just monitored the battery voltage and for that the ADC approach is better.

Which circuit and code you use depends upon what it is you are wishing to accomplish.

Terry

Terry - I have attached a schematic of my circuit using the voltage divider. I drew it up really quick using paint, so it doesnt look pretty. Also, the battery input should be +12 and -12, not +12 and -11. I also figure out were to put that voltage divider ground, im just running it into the chip ground. (i will post a proper schematic here shortly, i am working on it now.)

So, i think ive got the circuit down but now i need to work on the program. All i want to do is run a program flashing some LEDS as a strobe light on my helicopter. When the LIPO reaches 9.5v (or so, just not below 9V) i want the chip to change the pattern of the LEDS to warn me that my battery is getting low and its time to land. So far, i understand i need to use the comparator on the 12f629 and compare the battery voltage from the divider to the internal voltage in the chip (supplied by a constant 5v).

Here is my frustration, I am new to all this and might be in over my head, but im not giving up. I understand how to blink a light and different flash patterns, but thats about as far as ive gotten. No matter how hard i look i cant seem to find a program to dissect or an example of what i want to accomplish and how to accomplish it code wise.

I hate to ask, but would it be possible for someone to write the picbasic pro code for me, a working program, so that i can run it and figure out how it works? I feel like if i just has a working program, a lot of it would make sense to me........