hand crank generator

Hand Crank Generator

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.

hand crank generator

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.

hand crank generator 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!

hand crank 5V generator


  • C2: 100nF
  • R1: 47 Ω¼ W
  • ZD1: 5.1V ½ W

Lab Note

  • 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

hand crank 3.3V generator

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  • jack

    Hi! Thanks for this information.

    I have a question. Why does this circuit use with the 100nF capacitor(C2)?

  • krokkenoster

    Just a point to look out for use a motor that if a battery is connected the motor runs and if reversed the battery then the motor runs in the different direction. Old cassette motors has a electronic speed regulator and this prevent the output. I made something similar a number of years ago all I used was the motor from the filter shaker of a “Tennant” road sweeper and I played a radio on it All I used were belts and pulleys as I did not have to worry about gear’s teeth not meshing I did this in 1979 These motors were 12 volt units and the output current was sufficient to light up a 12 volt 10 watt globe. I heard the story the guys went out hunting and somebody left the radio on and when they returned the battery was dead as a dodo bird. The nearest service station was 75 miles away (c.a.1930) One guy stood thinking and the other one started to take the battery out.He didn’t feel like carrying the battery all the way. He removed the generator and held it against a wheel that they jacked up. They spinned the wheel for some time and refitted the battery and cranked the engine and the drove away. You can only do this with a generator (remember them?)and not an alternator as it need some current to excite the field of the rotor!!

    • T.K.Hareendran

      Thanks for the feedback! Fortunately the plastic gear robot motors are simple dc motors without any electronic speed governors. Another experiment with one discarded-stepper motor gives very rich output.

  • Jim Keith

    Great idea! Avoid SMD by using this TO-92 LDO regulator from Texas Instrument: LP2950-50 (5V), LP2950-33 (3.3V) and LP2950-30 (3.0V). All are $0.49 each from DigiKey.

    • T.K.Hareendran

      Thanks for your valuable feedback & suggestion dear Mr. Jim Keith. I will try using the LP2950-XX series as soon as possible!

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