- the wireless receiver only produces pulses (12v for on , -12v for off), so a regular relay cant be used because once the pulse is gone , it wont conduct , and i cant find an impulse relay.
- i want to use a microcontroller, but is there a micro that can take -12v as a logic zero and +12v as a logic one.
-if i cant get one of these, how can i configure the circuit to be used with a regular microcontroller.
-can i use a voltage regulator this way:i/p:12v , o/p:5v.
it requires four 0.1uf capacitors and it works by if there is +12v in an input it will output 0v which you can use in most 5v micro controllers. if it has -12v in the input it will output 5v. Are you sure +12v equates to a logic one because in the RS232 specification it is the other way around where a positive voltage is logic 0. That's how the MAX232 works.
If not you will need to build an inverter or invert the signals in code
the wireless receiver takes its vcc from the car battery and produces +12v or -12v normally to open or close the doors , but i want to use this singal to switch a motor (water pump) on and off.
For inputs of 15V down to 3V it will output 0V
For inputs of -15V up to -3V it will output 5V
It seems this is inverted from what you want but a 7404 or a transistor can be used to invert the logic. The beauty of using the MAX232 and the inverter is that you do not have to work with transistors and the resistors required to make the work right.
If you do want to go the transistor route that is ok too. **broken link removed**