Every year when you change smoke alarm batteries, you end up with a handful of 9 volt batteries that are essentially okay, just a little discharged. If you don't have any other devices that use them, then they often just end getting recycled or even in the bin.

This kit clips onto a 9 volt battery and turns it into a torch, lantern or flasher. It consists of a tiny PCB (27mm x 17mm) with two battery contacts, two LEDs, a resistor, a trimpot and a switch.

This kit features a 4 position switch, giving 3 modes, plus off:

Both LEDs on: both LEDs are powered at the current set by the resistor, around 20mA.

One LED on: One LED is powered by the current set by the resistor. This allows higher current through the first LED, or to drain the battery down to close to 3V to make full use of the battery.

Low: This drives either one or both LEDs via the resistor and the additional 10k trimpot. This lets you set a very low brightness mode for use as a marker light or where you only need a small amount of light for a long time. Current can be less than 1mA in this mode. You select whether this mode applies to one or both LEDs by small solder pads on the PCB.

Makes a great pocket emergency torch using narrow angle LEDs or a general emergency light using wider angle LEDs. It also works well as a hazard flasher using red or amber flashing LEDs.

Kit does not include a 9 volt battery, just the components required to make the torch. Supplied with two narrow angle and two wide angle LEDs for you to choose from.