The eternal torch in the kinder

Having a very energetic dog that runs around without a break for the ball, we decided to use it, having made such a device so that when jogging to save some energy. We will make a keychain on the neck with a LED. In the morning he will be charged for a walk, and in the evening he will glow and become a useful gadget, since we have a black dog and in the dark evenings it is completely invisible.

We will need

  • - Any LED (we used the 3-color chip inside, it smoothly shimmers with different colors);
  • - The case for the keychain (we used the kinder box);
  • - Any old mechanism from an old watch;
  • - Some neodymium magnets;
  • - A ring from a bunch of keys;
  • - Diode Bridge;
  • - Switch, etc.

Manufacturing forever first flashlight in the kinder

The eternal flashlight in the kinder
We get neodymium magnets from the boxes with magnetic clasps, you can also get them from old headphones, from speakers and non-business phones.
Eternal flashlight in the kinder
We collected a small stack with 8 small magnets,You can also use one magnet approximately as in the picture.
The eternal flashlight in the kinder
Making a small cylindrical base of paper, where the magnets will freely pass, also install two paper washers on the cylinder, for the convenience of winding the coil. For strength, we saturate the paper structure with superglue and let it dry.
Eternal flashlight in the kinder
We take the wire for winding the coil from the old cheap Chinese watches.
Eternal flashlight in a kinder
We need to wind from 500 to 1000 turns. For convenience, we will use a drill-screwdriver, with his help we managed in a few minutes.
The eternal flashlight in the kinder
After winding to protect the coil, carefully isolate with electrical tape.
The eternal flashlight in the kinder
Solder two small copper wiring to the coil terminals, this will be the place where the coil is connected to the circuit. Insulating tape fix the copper wires along the base, and solder the wires to them.Hot-glue we isolate the place of soldering and at the same time fix it to the body.
The eternal flashlight in the kinder
Throw the magnets inside the coil and seal them on both sides with paper plugs.
The eternal flashlight in the kinder
The place of attachment of the keychain will be made of a clip, twist the loop and fasten it to the kinder. Inside we move the antennae loops on the sides and so that it does not jump out and fix with hot melt.
Eternal flashlight in the kinder
On the other side of the kinder, pierce with an awl two small holes for the legs of the LED, apply hot melt glue and glue the LED to the kinder by installing it in its place.


The eternal flashlight in the kinder
The electrical circuit is simple, the essence of its work is that when you run a dog, the key chain around your neck will shake, which will cause the magnet to shake in the coil. Bouncing magnets will pass along the winding which will give bursts of small amounts of alternating electricity. Next, the bursts will be leveled by a diode bridge and recharge the Li-PO battery.When evening comes we will turn on the switch and the accumulated electricity will power the LED.
Eternal flashlight in the kinder
Solder the diode bridge to the coil and the battery. The eternal flashlight in the kinder
Set the switch in its place and put everything together. Check, everything is lit. "style =" max- width: 100%; " alt="The eternal flashlight in the kinder"> The coil is securely glued inside the case so that it does not hang out inside the kinder.
The eternal flashlight in the kinder
The key ring shines brightly and the dog is visible from afar, we also have a three-color LED with a microchip inside. The keychain changes its color smoothly, it looks very beautiful.


During the operation of the keychain, we noticed a problem, unfortunately the coil energy generated, is not enough for us to charge the lithium-ion battery, also part electricity is dissipated on the rectifier bridge, and to fix everything, you need to redo the circuit. Instead of the usual diodes on the rectifier, you need to use schottky diodes, for example, ss14, and instead of the battery use an ionistor, this will give the opportunity to accumulate even small charges from the coil.You will also have to make an auto-oscillating step-up voltage converter to power the LED from the ionistor. We will use a 2N5551 transistor, KT315, S9014 or any similar low-power transistors. The transformer TR1 consists of two windings, 1-setting and 2-power with a midpoint. The circuit works due to bursts of self-induction of the choke, the self-induction voltage can exceed the supply voltage tenfold. The transformer is wound on a ferrite ring, which can be found in the old economy lamps (Ring size is not critical). Both windings have 20 turns of 0.3 mm wire. The end of the first winding is connected with the beginning of the second one and this is our middle point. See the picture below and the winding principle.

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