Introduction: KEY RING TORCH

About: Now I am a retired person, who enjoys life and making small things to pass the time keep myself busy.

In this project a Joule Thief has been used as it is small and pocket size.

It also give long life to the battery.

The PVC cover of a toothbrush head is used as the container.

Discarded Motherboard Battery of 3 volt is used as a power source,

as it is small in size and packs a lot of power.

A micro switch is used because it cannot stay ON in your pocket by accident.

This can also be used as a Continuity Tester with a slight modification.

Step 1: List of Parts.

1. A small PVC container.

1. Micro Switch.

1. Disc type PC. Motherboard Battery.

1. Transistor BC 337

1. Electrolyte Capacitor 10uF / any Voltage.

1. Disc Capacitor 470pF

1. Resistor 2.2K

1. Ferrite core (taken out of a CFL light)

10. Turns of double 0.5mm copper wire for the coil.

1. Extra bright White 5mm LED.

Step 2: The Circuit

Follow the Circuit and solder the parts on a small  thin PVC sheet,

or a cardboard and cut to fit the PVC container.

Fix the Micro switch on top of the container.

Drill a small hole for the LED.

Step 3: The Inner Stuff

Here you can see how all the parts have been fixed on the PCB,

this is for your guidance.

Step 4: Placement of Parts

This is an enlarged view of the PCB.

Maintain polarity.

Step 5: The Continuity Tester

This is the Circuit diagram of the Continuity Tester.

Only one change has been made, instead of the Micro Switch,

two leads wires have been taken out from the switch connection to test other components.

Step 6: The End

Photograph of the Continuity tester.

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    6 Discussions


    8 years ago on Introduction

    Good one Bro nice way of displaying project work........................


    8 years ago on Introduction

    Good job - nice application of the JT idea.

    The sensitivity of the continuity checker can be improved by disconnecting the wire from the resistor to the base of the transistor and putting the test leads there - you'll then be able to tell resistances up to 15k by the brightness of the LED.

    Naturally you'll have to replace the switch!


    8 years ago on Introduction

    Nice job. A multitasking Instructable no less. Unfortunately I already have both of these in other forms so I won't be making them, but very good ideas and very green none the less.