Low voltage projects

Addressable LED strip/chain controller
Controller for addressable LED strips (WS2812/WS2812B) or chains for 5-60 LEDs. Based on the ATtiny85 microcontroller. With music controlled effects.
Created: 2023/12/20
Last modified: 2024/01/01

Ultrasonic source
Ultrasonic source usable as an educational tool or as a powerful ultrasonic animal repeller.
Created: 2023/08/15
Last modified: 2023/08/15

Live wire/cable detector
Two versions of a simple circuit usable for detecting live wires - using capacitive coupling.
Created: 2021/09/30
Last modified: 2021/09/30

Hot air station
Analog hot air station using an 858D handle. Temperature and air flow control. Simple circuit with LM358 - schematic diagram and description.
Created: 2020/12/11
Last modified: 2020/12/11

Very low voltage Joule thief - voltage booster for LED
Germanium transistor based Joule thief variation able to run on 55 mV. Capable of running an LED using a Peltier module + body heat.
Created: 2020/12/11
Last modified: 2020/12/11

Lithium cell charge level indicator
Simple charge level indicator for rechargeable cells based on the LM3914 IC. Can be easily modified for other voltages/battery types (Pb...)
Created: 2020/12/07
Last modified: 2020/12/07

Nixie clock
Small nixie clock based on ATtiny88, DS3231M, MMBTA92, MMBTA42, MC34063
Created: 2020/10/18
Last modified: 2020/10/18

Boost converter for 3 watt UV-C lamp
DC-DC converter designed for powering 3 watt UV-C lamps from 3 to 5 volts, including Li-ion batteries
Created: 2020/07/24
Last modified: 2020/07/24

Low power LED flasher 2
Low power LED flasher with up to 10 years runtime on a single AA battery
Created: 2020/05/04
Last modified: 2020/05/04

9 V Ni-MH charger, LED tester
Simple 5 V (USB...) powered 9 V NiMH charger (7.2/8.4 V) also usable as a LED tester
Created: 2020/02/25
Last modified: 2020/02/27

Decorative neon lamp supply
Simple voltage converter for decorative neon lamps (flicker flame type) operating from a 5 V power supply (for example USB).
Created: 2019/12/20
Last modified: 2019/12/20

Inductor saturation current tester
Device for testing saturation current of various inductor and measurement of parameters of inductor cores using current up to 50 A.
Created: 2019/12/08
Last modified: 2021/03/20

I-V curve tracer
Tool for measurement of I-V curves (ampere-volt curve, current-voltage characteristic) using an oscilloscope.
Created: 2019/12/07
Last modified: 2019/12/07

Automatic fan control
Temperature based automatic fan controller using LM358.
Created: 2019/12/07
Last modified: 2019/12/07

Self-oscillating step-down LED driver
Two transistor self-oscillating buck (step-down) converter for LEDs (300 mA).
Created: 2019/11/29
Last modified: 2019/11/29

Photodiode based radioactivity detector
Beta/gamma detector based on common photodiodes (BPW34).
Created: 2019/07/11
Last modified: 2021/03/11

Avalanche pulse generator
Generator of fairly short pulses with short rise time and high amplitude.
Created: 2019/05/10
Last modified: 2021/02/27

200 mW laser + constant current source
200 mW laser with a simple IC-less constant current power supply
Created: 2018/12/28
Last modified: 2018/12/28

Constant current 1W LED driver (II.)
A small MC34063 based constant current supply. Used for soldering gun modification (incandescent to LED).
Created: 2017/12/09
Last modified: 2017/12/09

Electronic dice
ATtiny13 based electronic dice powered by a CR2032 battery.
Created: 2017/06/03
Last modified: 2017/06/03

Rechargeable battery analyzer
ATmega328P based capacity & internal resistance meter + dummy load
Created: 2017/05/28
Last modified: 2017/12/23

Super simple LED flasher
An extremely simple circuit. 4 parts total.
Created: 2016/09/28
Last modified: 2021/02/22

Low power LED flasher
A microcontroller-based flasher with 15uA power consumption
Created: 2016/08/24
Last modified: 2016/08/24

Wireless energy transfer
Resonant Royer-based wireless energy transfer circuit
Created: 2016/06/20
Last modified: 2016/06/20

TDA2003 based amplifier
A small 5W/channel amplifier
Created: 2016/06/06
Last modified: 2016/06/06

Constant current LED supply
MC34063 based switch mode LED current regulator
Created: 2016/05/18
Last modified: 2016/05/18