There are many designs of LED flashlights. The most convenient of them are those that run on batteries. In such a flashlight, you do not need to change the batteries - it is enough to periodically charge it, like a cell phone.
Instructions
Step 1
Take an old faulty cell phone. It must be old enough that the battery in it is not a lithium-ion, but a nickel-metal hydride. Use a charger from it.
Step 2
Change the plug on the charger to another one for which you have a mating part.
Step 3
In the housing that you want to use for the flashlight, drill a hole for the mating connector. Install it in this hole. With the charger connected, use a voltmeter to determine the polarity of the voltage at its contacts.
Step 4
Glue the battery to one of the sides of the case so that you have access to its contact pads.
Step 5
Connect the positive terminal of the mating connector to the positive terminal of the battery through a current-limiting lamp for voltage 12 V and current 0.1 A. Connect the negative terminal of the mating connector directly to the negative terminal of the battery.
Step 6
Drill a hole for the toggle switch in a convenient place in the body. Install it in this hole.
Step 7
Take four white LEDs and two 100 ohm 0.5 W resistors. Make up of them, observing the polarity, two chains in series, each of which consists of two LEDs and one resistor. Connect the chains in parallel. You will get a lantern emitter.
Step 8
Drill holes for LEDs in the housing. Insert them into these holes. From the inside of the case, fill the emitter with "Moment" glue or similar in such a way that it does not hit the extreme terminals. Wait until the glue is completely dry.
Step 9
Connect the positive terminal of the emitter via the toggle switch to the positive terminal of the battery. Connect its negative terminal directly to the corresponding contact pad of the battery.
Step 10
Open the toggle switch. Connect the charger included in the mains. The current limiting lamp should light up weakly. Leave the flashlight to charge for fifteen hours.
Step 11
Stop charging. Now the device can be turned on and off with the toggle switch. When the brightness of its glow drops, turn off the flashlight and recharge it.
