Introduction: Micro-usb 30F Supercapacitor Flashlight

This is an example of a supercapacitor flashlight that can be charged with a standard 1A smartphone charger.

French people can find the entire description here :

Step 1: You Will Need

- perfboard

- micro-usb connector

- 1.1A Polyswitch

- 4.8 ohm 1 Watt resistor

- 1000 ohm, 82000 ohm, 220 ohm and 11.4 ohm 1/4 Watt resistors

- buck converter (RC Airplane Module Mini 360 DC Buck Converter Step Down)

(4.75V - 23V to 1V - 17V)

- 1N5817 diode

- Supercapacitor 30 Farads 2.7V

- TL431 (adjustable shunt regulator with 2.5V Vref)

- green LED 3mm

- button

- boost converter (mini DC DC 0.8 - 3.3V to 3.3 V Step UP Boost converter)

- white LED 5mm (20000 mcd, 3.1 to 3.4V)

- soldering iron with solder and flux

- jumper wires

Step 2: Adjust the Buck Converter

With the micro-usb connector and a breadboard, you have to connect the buck converter, the Polyswitch, the 1N5817 diode and a 1000 ohm resistor.

You connect a voltmeter to the resistor.

Then you turn the buck converter screw to obtain 2.6V.

Step 3: Turn on a Green LED When the Supercapacitor Is Charged to 2.5V

The TL431 device is a three-terminal adjustable shunt regulator. The output voltage can be set to any value between Vref ( 2.5 V) and 36 V.

So it's easy to turn on a LED on 2.5V with a TL431...

Step 4: Breadboard and Perfboard Supercapacitor Flashlight

When the switch is engaged, the supercapacitor feeds a small boost converter which boosts the voltage to 3.3V to power a LED through a 11.4 ohm resistor.

If you need more information, you can read the original description (in french) of this supercapacitor flashlight here :

Enjoy !

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