3 digit battery voltmeter (0 to 20VDC) for cars and motorbike

Easy and Simple Voltmeter Circuit

In every automobile info cluster, everyone needs to know about their battery status, some cars/motorbikes having that features but i don't think they all are showing in volts. some times we need to know about battery charging voltage for overcharging, over draining etc. it will helps user to troubleshoot their electrical systems as well.

Circuit:

The Above figure is circuit of voltmeter, I have used bus over there (blue color) to simplify the work.

• Note: Before connecting high voltage to the network, Make sure of configuration of input voltage divider network (ADC input pin connection) they are R12,R14,R14. After confirming voltage at the junction of R13 & R14 is < =5.1V, connect to microcontroller input.

Components: (some components in circuit diagram is not same as real parts)

• IC1:PIC16F684
• IC2: 7805 (I recommend Filtered voltage regulator circuit)
• R1,R2,R3: 1K Ohm.
• R5 to R11: 330Ohm or 470Ohm.
• D1:5V zener diode.
• T1,T2,T3: BC547
• DIS1,2,3: Common cathode 7 segment display.

Description:

This voltmeter can show voltage from 0.1V to 20.0V
The battery voltage is fed to the resistor voltage divider network to reduce voltage for 20V range to 5V range. That reduced voltage to the ADC of PIC microcontroller. the controller will convert ADC Hex value and show them in multiplexed 3 digit 7 segment display.

PCB,Project files and .HEX files

PCB

Simulation circuit

Project files:

Yandex Folder

Arduino sketch and circuits are coming soon...

I tried my best to simplify and provide all the information, If you feel problem in any ask me for solutions.