A bench prototype that shows live V, I, P and energy on an LCD, takes keypad input, and switches a real load through a relay.
Overview
Power feels close to home in Bangladesh — bills, load shedding, dodgy wiring, appliances that die because the voltage dipped. That is why I keep coming back to energy-monitoring projects.
This one measures voltage, current, power and energy, shows them live on an LCD, lets you punch in commands on a keypad, and switches a connected load through a relay. It is small, but it covers the three things a smart meter actually does: measure, display, control.
Measurement module feeds electrical data to the controller. Firmware updates the LCD, reads keypad commands, and switches the load-control stage according to the selected test or control mode.
Project photos
Energy meter demo with LCD readings, keypad, wiring, and load-control hardware.
Videos
Implementation details
Firmware
Firmware reads electrical parameters, calculates or displays voltage, current, power and energy, handles keypad input, and drives the relay/load-control hardware.
Power
Prototype handles mains-related measurement and switching; isolation, enclosure design, fusing, and wiring separation are important before field deployment.
Components / BOM
Microcontroller board, Energy measurement sensor/module, LCD display, Keypad, Relay or load-control module
Engineering challenges
Doing measurement, UI and load switching at the same time without one starving the other. Mains-side wiring needs respect — fuses, isolation and a tidy bench setup, even for a prototype.
Solutions
Kept measurement, display refresh and relay control as separate concerns in the firmware so the UI never feels frozen. Wired the load side carefully and tested with a controlled bench load before anything bigger.
Results & metrics
Live meter readings update smoothly while the relay switches an actual load on the bench. Easy to demo without a laptop.
Future improvements
Add wireless telemetry, data logging, a small dashboard, prepaid-style modes and a proper metal enclosure with isolation that I would actually trust in a shop.
