Future Dreams: Voltage, Temperature & Frequency Meter

Voltage, Temperature & Frequency Meter

With PIC Micro controller

Features…

Voltage, Temperature and Frequency can switching to each others using push buttons.
Voltage Meter can measure DC voltage between 0v to 50v.
Frequency Meter can measure frequency up to 65KHz.
Temperature Meter can use between 0⁰C to 150⁰C.
Every functions can paused using push button.

Instructions…

Voltage meter

Volt meter can measure dc voltages up to 50v. 5V is the maximum voltage can handle PIC microcontroller, as it is voltage divider (10K,1.1K) use for convert 50V to 5V . 5v zener diode use for safety of PIC microcontroller analog input pin.

Temperature meter

Temperature meter can use between 0⁰C to 150⁰C. But LM35 sensor can use between -55⁰C to 150⁰C. Sensor’s resistant is changing opposite to temperature, as it is maximum temperature gives maximum voltage output(5v) and minimum temperature gives minimum voltage output(0v).

Frequency meter

Theoretically, frequency meter can use up to 65KHz, that is because this circuit made by using Timer 1(16bit) of PIC microcontroller. Timer 0 can only measure up to 256Hz, that is because timer 0 is 8 bit timer. Transistor part is use for safety of microcontroller from amplitude of wave signal. This circuit can apply 12v amplitude or more changing transistor base resistor value(4.7K). I tested it, using 12v amplitude square wave signal.

Troubleshooting…

If you have problem about accuracy of voltmeter, temperature meter and frequency meter, you can change values (*1,*2,*3) using Guide 01.