If you’re wearing a FPV headset, goggles, or perhaps have a ground station being powered off a lipo battery you’ll want a low volts warning, but not a loud ear-splitting alarm going off right next to your ear!

Based on low cost low volts alarm from Hobby King, here’s an easy solution.

It simply involves removing one of the piezo buzzers off the board, and replacing it with a standard single-turn 1kΩ trimpot.

This video demonstrates the modification, and you can hear what a difference this makes:

One of the piezo buzzers is de-soldered from the board.

View from solder side:


View from components side:


A cermet style trimpot is a close, but not perfect, fit into the PCB holes a shown:


This is the board with the trimpot installed.


The only thing to do now, is to cover the board in 20mm clear heatshrink, and make a hole in it to be able to adjust the trimpot.