Shared Projects by Renew-Magazine-1-year-flashlight

This is the PCB for a flashlight that runs continuously for one year, when powered by three rechargeable 2400mAh NiMH batteries.

Note that the batteries must be of the low-self-discharge type, or the batteries will go flat faster.

The PCB is designed to fit into a 4xAA battery holder, in place of one of the batteries.

The description of this circuit is published in Renew magazine, issue 166, available from January 2024. https://renew.org.au/renew-magazine/

Note that there is a typo in the above magazine article: in some places in the text, the capacitor has been described as “10mF”. This should have said “10uF”, as it did in the pre-prints of the article that I received.

Tools needed for assembly:

• Soldering iron and solder.

• Wire cutter.

• Fine-point pliers, often called “needle nose” pliers.

• A coat hanger made from wire, and two wooden spring-type pegs.

• a file or some fine-grit sandpaper.

Parts list:

• the PCB, ordered from Osh Park.

• a paperclip made of wire, approximately 25mm (1-inch) long.

• one battery holder that takes four AA batteries. Jaycar PH9200 is suitable.

• one 100-ohm resistor, 1/4W rating.

• one 3.3k resistor, 1/4W rating.

• two 10k resistors, 1/4W rating.

• five 220k resistors, 1/4W rating.

• one BC546 transistor (BC547, BC548 and BC549 are suitable alternatives).

• three BC557 transistors (BC556, BC558 and BC559 are suitable alternatives).

• one 10uF electrolytic capacitor with 6.3mm diameter or smaller, and 6V or higher rating.

• one superbright 5mm LED. Jaycar’s ZD0196 is suitable, and it appears to be a Cree C512A-WNN.

There is a PDF of the assembly instructions, with pictures, on GitHub.

To download the instructions, go to https://github.com/Renew-Magazine-1-year-flashlight/Assembly-Instructions

Click on the green “<> Code” button, and then click on “Download ZIP”.