This circuit can come handy when you are camping in a remote area where there is no electricity available to charge your mobile phone or tablet's battery. If you can make tea or light a fire, you can as well charge your device using this circuit. It uses a simple Thermoelectric device.

Thermoelectric Modules

A Thermoelectric generator, or TEG (also called a Seebeck generator) is a solid state device that converts heat (temperature differences) directly into electrical energy through a phenomenon called the Seebeck effect (a form of thermoelectric effect). Thermoelectric generators function like heat engines. Connect a TEG module to a vessel in which something is to be cooked and it will start generating electricity.

Step 1: Gather Tools

The parts needed are

1. Thermoelectric Module

2. 1N5817 Schottky Diode

3. Duct Tape(To affix TEG to vessel)

4. 47uF Capacitor

5. DC-DC Boost Converter(PFM Module)

Step 2: Build Your Hardware.

Thecircuit is built by a 5v Thermo electric Module, Schottky diode 1N5817 and DC-DC boost converter module. Working of this small DC-DC boost converter module is based on pulse frequency modulation (PFM) technique.

A PFM converter is an alternative DC-DC power converter architecture that uses a variable frequency clock to drive power switches and transfer energy from input to output. Because the drive signal’s frequency is directly controlled to regulate the output voltage, this architecture is referred to as PFM. DC-DC converter with constant-on-time or constant-off-time control is a typical example of this architecture.

In the circuit diagram, the negative terminal (black wire) of Module is treated as the positive output terminal, connected to PFM module (board 1) through polarity guard diode 1N5817 (D1). The PFM module is connected across buffer capacitor (C1) to get a USB-standard 5V DC output through its USB (A-type) connector. You can connect the mobile with data cable and charge your mobile from the output of DC-DC Boost Converter.

Step 3: Place Thermo-electric Module

Simply add water and place the water on fire. Place the thermoelectric generator on the vessel. It will start generating elctricity in seconds. Place the high temperature cable to the back of TEG and the charging will start.

The larger the temperature difference between the water in the vessel and bottom of the vessel, the more electricity, TEG will produce.For example melting a snow is a great way to generate electricity as the temperature difference is higher. Do not worry about overpowering your device as circuit built in regulator which ensures that your USB device charges safely.

Step 4: Connect Your Device

The regulator outputs five volts(USB Standard) and upto 100-milli amp. of current, which is the most any smartphone/mp3 player can handle. This means that, when you are charging your USB device with TEG and circuit, you will get the same charging power as you would from your wall outlet charger at home.

Now connect your mobile and hurrah!! You have successfully made phone charger from heat.