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Low battery alarm

Matan-Vinkler·low-battery-alarm

Low battery alarm PCB layout, top view — open source board by Matan-Vinkler

About the Low battery alarm PCB

Low battery alarm is an open source PCB design by Matan-Vinkler, published on GitHub under the MIT license. It is a 2-layer board measuring 56.3 × 41 mm, with 12 components from 12 distinct parts.

By type, the board carries 3 resistors, 2 capacitors, 1 transistor, 1 connector, 1 buzzer and 1 fuse.

It belongs with the power & battery designs in this gallery.

From the project

A simple PCB design that detects low battery levels using a high-voltage divider and triggers a buzzer via a 5 V DC-DC module. Includes input filtering, surge protection (TVS), and transistor-based threshold switching. KiCad project + BOM + gerbers.

- Revision: vNOV 2025 - Author: Matan Vinkler - Date: 27-11-2025

This PCB implements a low-battery alert system for a 48 V DC battery. When the battery voltage drops below 25%, the board activates a 5 V buzzer and indicator LED (optional).

The design fulfills all assignment requirements:

Accepts 48 V DC input using a standard connector Monitors battery voltage using a high-value resistor divider Activates a buzzer once charge level drops below 25% Includes a filter stage to reduce voltage spikes and noise caused by variable loads Generates a stable 5 V rail using a DC-DC converter Provides…

Low battery alarm bill of materials (BOM)

12 components, 12 distinct parts.

QtyPartRefs
1
BC547
Q1
1
Jack-DC
J1
1
Buzzer
BZ1
1
500 mA
F1
1
IA4805D
PS1
1
SMBJ58A
D1
1
47 uH
L1
1
100 uF
C1
1
0.1 uF
C2
1
220k
R1
1
3.3k
R2
1
75
R3

Low battery alarm design files

The KiCad project lives in the Matan-Vinkler/low-battery-alarm repository on GitHub; these links point at the commit this page was built from.

Low battery alarm: common questions

How big is the Low battery alarm PCB?

The Low battery alarm measures 56.3 × 41 mm, has 2 copper layers and is 1.6 mm thick.

How many components are on the Low battery alarm?

12 components, from 12 distinct parts. The full bill of materials is listed on this page.

Where can I download the Low battery alarm design files?

From the Matan-Vinkler/low-battery-alarm repository on GitHub, which has the KiCad layout and the schematic; the links under Design files point to each one.

Can I use the Low battery alarm design in my own project?

Yes, under the terms of its MIT license, which Matan-Vinkler chose for the repository.

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