3 DIGITS VOLTMETER WITH PIC18F1320

18f1320_voltmeter

https://postimg.org/image/sy5g6cq77/

This is a small, hand-made, 3 digits voltmeter with PIC18F1320. The voltage is displayed on three common anode 7 segments LED displays of your choise. They are multiplexed and driven by small transistors. The maximum input voltage is 30 VDC and can be trimmed with a small trimmer resistor that changes the ratio between the two resistors of the input voltage divider. The analog input of the μC is protected by a small zenner diode rated at 5.1 volts. As result, you can see volts with one decimal digit.

The displays need current limiting resistors (R8-R15) in series with the μC outputs. Their values depend on the specific type of display you gonna use. I used resistor networks of 220 Ohms. They can be clearly  viewed in the next five pictures.

The circuit is supplied by an LM7805 regulator and is protected from opposite polarity with a diode.  The PIC18F1320 is a little bit overkill for such a circuit, but I had it “sitting” in my drawer. Everything was assembled on a small piece of breadboard and wired with Kynar wire. For long lasting opperation, a small heatsink is good to be placed on the regulator. Some pictures of this one-afternoon project:

2014_10_17_22_26_272014_10_17_22_25_112014_10_17_22_24_432014_10_17_22_24_032014_10_17_22_23_242014_10_17_22_21_342014_10_17_22_21_062014_10_17_22_19_44

The code was developed with MPLAB IDE and HI-TECH C Compiler and is free-to-use for anyone who desires to make this mini voltmeter. Just use the link below:

https://drive.google.com/open?id=0B_CGrhtJ7yX5cGhiN3pfN3M0YXM

In this link, you can find seperate folders for firmware and hardware. The schematic was designed with Altium DXP, but there is no PCB.

There is also a github repository at https://github.com/manolena/PIC18F1320-mini-voltmeter.

Have fun!

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s