I want to convert a signal that is 12v-14v (high, 0v low) to RS232... My guess would be to use a Max232 chip, but I'm not sure of the electronics to go with it, could one of the electronics guru's help me out please?
The MAX232 (or other MAX RS232 transciever flavor) is the best way to go. Because you have 0V-12V swing, you will need to cut that down to 5V swing. You could either use a voltage divider circuit, or an opto-isolator to do this.
Well, a voltage divider would be better otherwise I'll have to use a regulator to get 5v. Ummm... could somebody help me with the voltage divider part as I'm not sure how they work.... I know it's just a resistor, but that's about all I know.
A voltage divider is two resistors in series between V+ and ground. Your desired voltage is at the junction between the two resistors and is equal to: V*R1/(R1+R2). So, in order to get 5v from 12v, R1/(R1+R2) needs to be 5/12, so the ratio between R1 and R2 would need to be 5:7. The resistance values should be fairly high so that they don't draw current that doesn't necessarily need to be drawn (plus they'll need to dissipate the current from the rest of the circuit as well).
