LED Night Light Use Joule Thief Circuits

I enjoy making illuminated devices such as the recent projects I have worked on - Joule Thief , Simple Flashlight With COB LED, Mini WLED Controller and various versions of PCB Christmas Trees.

Recently, I discovered the Joule Thief LED Night Light by ledartist, which is a great idea that uses a small circuit called a Joule Thief to boost the voltage of batteries. They also added a light sensor that automatically turns on the light when it is dark. Therefore, I decided to make my own version.

What Is A Joule Thief ?

A joule thief is a minimalist self-oscillating voltage booster that is small, low-cost, and easy to build, typically used for driving small loads. 

It can use nearly all of the energy in a single-cell electric battery, even far below the voltage where other circuits consider the battery fully discharged (or "dead"); hence the name, which suggests the notion that the circuit is stealing energy 

The circuit is a variant of the blocking oscillator that forms an unregulated voltage boost converter. The output voltage is increased at the expense of higher current draw on the input, but the integrated (average) current of the output is lowered and brightness of a luminescence decreased.

Because the joule thief can utilize the energy in a battery even below the voltage where other circuits consider it fully discharged, it is considered an eco-friendly circuit design

As the circuit is very simple, materials are easy to get. 

Custom PCB x 1

CdS Photoresistor x1

1k ohm x1

100k ohm x1

10k ohm x1

50k ohm trim pot x1

22pF x1

470uH x1

SS8550(or just about any general purpose PNP transistor) x1

SS8050(or just about any general purpose NPN transistor) x2

LED x2 or COB LED

AAAx1 battery box X 1

I hope to make it as small as possible, so I am using SMD components as much as possible. I have added two types of LEDs to the PCB: SMD LED and COB LED. During soldering, I have the option to choose which LED to solder onto the PCB.

I use EasyEDA to design PCB and upload the design to JLCPCB.com to manufacture PCB.

JLCPCB make high quality prototyping PCBs for people all over the world. They have over 300,000 worldwide customers with over 8000 orders per day! They have over 10 years of manufacturing experience and are super reliable. Try it for your self and get 10 PCBs for just $2 at JLCPCB, New registered users US$54 offer , Order here

You can use my gerber files to ordel your own PCBs, and build this DIY Project.

Just a quick example how to order PCB from JLCPCB.com:

1)press "QUOTE NOW"

2)press "Add your gerber files"

3)upload zip or rar

4)all properties could be left default

In just a few days, I received the custom PCB from the factory and was able to enjoy the DIY assembly process. With the help of the custom PCB, I was able to assemble the entire quickly and easily. The entire assembly process can be viewed on YouTube

Insert a battery and take the Night Joule Thief to a dark room. LEDs should light up.

Adjust the trimmer pot (VR1) so that the LEDs turn on at the desired darkness.

With the help of custom PCB manufacturing, I was able to easily create the LED Night Light with just a few simple steps.I hope everyone enjoys my creation.