No one has encountered a situation where a smartphone swears abusively at a low battery, and the light turned off as luck would have it? I think that many. Or the same story with your favorite netbook, which has 12 volts power? Or do you need an autonomous light source that is as independent as possible from the presence or absence of voltage in the network? Unfortunately, to think about creating such a device made the civil war, already going on almost at the doorstep of my house :(
Thank God, I know how to handle a soldering iron, in the pantry there is a whole box of electronic junk, which is nowhere to go, and it is a pity to throw it away, and then a video with a similar man-made miracle got on the network from which toggle switches, bolts and contacts stuck in all directions. But it worked, and it worked great! Here, I think, just what you need. The author of the video especially did not disclose the scheme, but it is not too complicated. I apologize, the artist from me from the word "bad" :)
As a case, I used a Chinese lamp Delux REL 500LED, which was killed by two years of operation
The battery there, instead of the standard 4 hours, held a maximum of 15 minutes, but I decided not to throw it out of the natural female hamster, but supplement it with two batteries from dead cell phones. The result was a capacious enough battery to work all night in the night-lamp mode. The stepper motor from the old dot matrix printer is found at the bottom of the box. Diode bridges could be assembled independently from Schottky diodes 5818, or torn from old flashlights, but I used ready-made assemblies in one 2W10 package. The only thing I had to buy was two capacitors with a total capacity of 11,000 microfarads and voltage stabilizers 7805 and 142EN8B, there were no such parts in my flea market. Capacitor C3 is taken from an old charger. I also needed two three-position switches, one of which was kindly provided by a gutted lamp, and the other was borrowed from an old flashlight, and a couple of meters of a thin two-color wire. What I didn’t find was the drill. Someone from relatives took "for temporary use", but never returned. But the need for inventions of the cunning, in the presence of self-tapping screws, a soldering iron and a sea of electrical tape, the matter was decided without it.
All. It was only up to the scheme and implementation.
From the very beginning, I did not want to hang a flashlight in the case. There is not much space there, but the LEDs also get warm. Therefore, I decided to make a conclusion of 5 volts to the USB port and the lamps on the corresponding plugs. By the way, there was a use of the removed LED panel, and it turned out a bright lamp.
One drawback - for about 40 minutes the panel sits the battery in half. I also made a night lamp and an ordinary lamp on flexible legs. The 12 volt output was fitted to the connector from which the lamp power supply was powered in a previous life. The shaft of the stepper motor fit perfectly into the hole for the nail slightly widened by the knife (the economical Chinese planned to hang the lamp on the wall), but the hole for the pin of the gear mechanism had to be melted with a soldering iron, simultaneously scolding forgetful relatives. Nothing, managed. And the lever on the gear made from a fragment of a bicycle spoke and a piece of a thin plastic tube.
The lamp and the charger worked properly, the battery from the engine was charging quite cheerfully, as reported by the green LED. By the way, it not only signals charging, but also does not allow capacitors to "pull" out of the battery. And then I felt lazy every time for half an hour to twist the handle. Having disassembled my freak, I soldered another USB port, taken from the extension cable gnawed by a cat, and soldered the USB plug from the same cord to the old charger from the cell phone. And it charges the device perfectly in the presence of 220 volts in the network. The only condition is that the switch "5v - 12v" should be in this neutral position. In these photos, a generator, charger, circuit and a set of lamps "for all occasions", including a 12-volt LED strip.
In addition, a fully working Chinese rechargeable flashlight was removed from the drawer with recharging, as it were, from the network. “As if” - because the plug was clearly collected by a blind Chinese man on a night shift: these stubs did not reach a single outlet in principle. I threw the plug, capacitor and diode bridge into the treasured box with junk, they will still come in handy, the USB port was soldered directly to the battery and stuck it in place of the plug. It is charged both from the generator and from the mains, and it charges mobile phones with a battery of not more than 1300 milliamps / hour. It really shines for 8 hours, although here the Chinese have not deceived ...
There are plans to build an external battery for 12 volts, but this will be a completely different story ... :)
