Here is the circuit of a compact hand powered generator that can awake little electronics by hand crank. This is a great vacation device that you can rely on to operate your small electronics. The prototype generates up to near 150mA of current at 5 volts, enough for a wide range of minuscule devices!
It is easy to use a small dc motor as the “dynamo” of a hand crank generator, but mechanical construction of the associated “gear-train” unit is an awkward task. That is why an easy method is used here. In this project, a commonly available 5V DC plastic gear robot motor forms the heart of the power generator. A 60mm dia robot wheel, fitted with a 40mm long pcb stud, works as the crank shaft.
Basic circuit diagram of the Hand Crank Generator is shown below. Diode D1 (1N5819/1N4007) is used for input polarity protection. While cranking, about 5 VDC available across the output terminals is stored by the super capacitor C1 (1F/5.5V) for a finite duration. If the output is not available while cranking the motor in clockwise direction, just reverse the connection of the motor wires at the input of the circuit.
- M1: 5VDC Plastic Gear Robot Motor
- D1: 1N5819/1N4007
- C1: 1F/5.5V Super Capacitor
The “raw” output available from this circuit can be used in a number of ways. At first, a zener-diode based 5.1 V regulator circuit is connected to the prototype to get a stable (low current) 5.1VDC supply. It’s fine!
- C2: 100nF
- R1: 47 Ω¼ W
- ZD1: 5.1V ½ W
- Prototype was also tested with 1N4007 as D1, and 2200uF/25V electrolytic capacitor as C1. However, for better efficiency try to use 1N5819 as D1 and the 1F/5.5V super capacitor as D1
- The raw ouput can be processed to get a stable 5V (or 3.3V) with the help of a lowdrop voltage regulator like LM 1117-5.0 ( LM1117-3.3) available in SOT-223 package. Tested application circuit is shown below
Componets bought from