Tag Archives: voltmeter


DIY Variable DC Power Supply with Display and PC interface

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A variable bench power supply is an important equipment in electronics lab for conducting experiments, prototytyping, and testing. This cool-looking DIY bench power supply provides fixed 5V and 12V outputs along with a separate variable DC output ranging from 1.2 to 25V. The on-board LCD display shows instantaneous output voltage, current, and power drawn, which are very important parameters during prototyping of a new project. The power supply can also be connected to a PC through RS232 port to visualize and monitor these parameters graphically on screen. The project uses Atmega8 microcontroller for measuring and displaying the electrical output parameters.

DIY variable power supply

DIY variable power supply

 

Yet another voltage monitor for car’s battery

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A couple of years ago I built a digital voltage monitor system for my car’s battery and its charging system. It plugs into the car’s cigarette lighter receptacle and displays the instantaneous output voltage across the battery terminals on a 4-digit seven segment LED display. I used Microchip’s PIC16F1827 microcontroller and it’s built-in Fixed Reference Voltage (FVR) module to achieve better A/D conversion accuracy while measuring the battery voltage. Here’s an instructable on building a similar device but using ATtiny13 microcontroller. Instead of displaying real battery voltage, however, this project uses three LEDs as visual indication of battery condition.

Car's battery voltage monitor

Car’s battery voltage monitor