We are all aware of about voltmeters (voltage meter), which is nothing but a device used to measure voltage between given two terminals. Apart from the basic usage digital voltmeters are also employed as panel meters for automation systems and robotics. There are analog and Digital voltmeters are available in the market. Have you ever thought about building a PIC microcontroller based digital voltmeter with seven segment display output? Here I’m explaining the constructional details of digital panel voltmeter using PIC16F877A microcontroller. It can measure voltage between 0V to 30V DC. Seven segment units are provided for digital voltmeter display which gives clear visibility of digits from long distance comparing to LCD display.
The program for digital voltmeter using pic microcontrolle is compiled using Mikro C. We are providing the .HEX file for this simple voltmeter absolutely free!
The following figure shows digital voltmeter panel circuit diagram with microchip PIC.
Components Required for Digital Voltmeter Using PIC Microcontroller
- PIC16F877A Microcontroller
- Transistor (BC548 x4)
- Resistor (1KΩ x 5; 10KΩ; 100KΩ; 22KΩ)
- Seven segment Display x8
- Crystal (20MHz)
- Capacitor (10µF, 33PF x2)
Working of Digital Voltmeter Using PIC Microcontroller
- PIC programming is quite easy if you have a perfect C compiler like Mikro C pro, MPLAB Hi-tech C etc.
- If you are new to PIC microcontroller I recommend to checkout our previous articles and Getting started guides for PIC MCU. You may also checkout our PIC Projects
- PIC16F877A has inbuilt ADC (Analog to Digital Converter) Module, I used ADC to read input voltage value.
- First of all let I discuss how do we measure voltage? Actually PIC’s ADC can measure 0V to +5V, but here our voltage range is 0V to +30V.
- Hence we can’t feed the input voltage directly to the controller’s ADC pins. Instead of feeding directly, input voltage is reduced by a combination of voltage divider resistors.