In this tutorial, we are discussing a DIY bicycle USB charger circuit. This will use the output power of a bicycle dynamo to produce a regulated 5V output to charge any electronic devices. A bicycle dynamo is a kind of generator that is attached to bicycles to produce electricity for the bicycle’s lights.
The wall chargers for your devices provide direct current at 5 volts. Whereas a bicycle dynamo hub usually creates electricity in the form of an Alternating current at 6 volts. Therefore we will change the electricity coming out of the dynamo hub into Direct current with the help of this circuit. This circuit is using only a few components, which helps in keeping the weight, size, and cost down and can easily be attached to your bicycle.
Hardware Required
| S.no | Component | Value | Qty |
|---|---|---|---|
| 1. | Bicycle dynamo | 6V/3W | 1 |
| 2. | Diode Bridge D1-D4 | 1N5822 | 4 |
| 3. | Capacitor | 2200uF/16V, 100nF, 33uF | 1, 1, 1 |
| 6. | Voltage regulator IC | LM2940CT-5.0 | 1 |
| 7. | USB Socket | Type A Female | 1 |
Circuit Diagram
Working Explanation
The alternating current generated from the dynamo is converted into the required direct current (DC). This is done by using a full-wave bridge rectifier having four 1N5822 Diodes. After the conversion, this signal is now passed through an electrolytic capacitor for filtering. The filtered signal is now sent to the Voltage regulator IC LM2940CT. This IC will give us our desired output of regulated 5 volts. Before going into the USB socket we will filter the output one more time by a capacitor to cancel out any residual noise.
A female USB socket of Type A is connected to the output of the circuit so that you can connect your devices. In this circuit, the dynamo used has a rating of 6V 3W but you can also use a 12V dynamo. If you’re using a 12V dynamo then change the 2200uF capacitor from 16V to 25V.
Application and Uses
It produces 5V output that can charge various electronic devices such as,
- Smartphone
- MP3 Player
- GPS
- Cameras, etc.
