hey! i need a circuit diagram for making a temperature and voltage sensor. I plan to use LM35 for temperature but have no idea for the voltage part. i want to display the reading on seven segment display. my options of microcontroller are PIC/8951.
temperature sensor - LM35 data sheet will help
Voltage sensor - Just a basic resistor divider circuit is enough, with about 2 or 3 resistors.hope you know what is a resistor divider circuit.
Based on the voltage levels you need to measure, you can choose the resistor values, so that the divider will convert the maximum measurable level to the max voltage the controller can aquire(probably 5 V)
If you need both the temperature and the voltage measured, you need to go for an ADC if you choose 89C51. PIC will work fine as it comes with built in ADC's. Use one for temp and other for volatge. As said by "cameo_2007", for monitoring voltage, just a resistor network will suffice whcih will then connect to the ADC pin....Cheers