People pedal powered computer charger

Author avatarVélo M² | Last edit 9/12/2019 by Clementflipo

People pedal powered computer charger DSC05302.JPG
The people pedal powered computer charger is a device that harvests human energy to charge a computer. The energy input comes from an ordinary bicycle in a stand that drives a generator. The energy output is the charging voltage of the computer.


The project Vélo M2 plays with PPP (people pedal power) applications. In Brussels we're having PPP open-air cinéma projections, PPP mobile fablab workshops and PPP music scenes and DJ sets. []

This projects takes people pedal power to a smaller scale, where we will be charging a computer. In order to demonstrate the accessibility, we're construction the device in a remote town in Sweden, Torsby.


- bicycle stand

- wood

- DC generator

- power display

- DC/DC converter

- cables, connectors and plugs


- woord or metalworking tools

- multimeter

Step 1 - People Pedal Power

People pedal power is a form of renewable energy. One human can produce around 75W electric power sustained for about 15min, or 50W during a longer period. This is enough power to be able to charge an average laptop. This energy can be harvested on a PPP device.

To find out more about People Pedal Power, visit our site

Step 2 - Overview

The PPP charging device gives an alternative for charging your computer. You on your ordinary bicycle will pedal while on a bike stand. The bike stand has a generator that is turned by the bicycle wheel by a roller. The power coming from the generator is converted to the DC voltage your computer needs to charge. We are adding a display in between to monitor the production.

Step 3 - Charging : adapting to the computer voltage

The aim of the people pedal power is to charge a computer. A computer battery is normally charges by an adapter that converts AC mains power to DC power. This charger will be only for YOUR computer.

Be informed :

- we want to charge with the same power as the adapter does

Check the voltage and the current at which the adapter charges your computer. Mine charges at 20V and 4.5A.

- you will be cutting your power cable

You can also chose to buy the plug separately and assemble a new cable.

Step 4 - Energy monitoring

Step 5 - Conversion : messy DC power to flat DC voltage

Step 6 - Generator : mechanical to electric energy

Step 7 - Roller : slow- to fast-rotation mechanical energy

The second etape is converting the slow-turning mechanical energy of the bicycle wheel to a fast-turning mechanical energy. Electric generators like high speeds.

Step 8 - Bicycle stand : dynamic energy to static energy

Step 9 - Bicycle : human energy to mechanical energy

The fist etape is the conversion of the human energy to slow-rotating mechanical energy. We are using an ordinary bicycle to harvest the energy.

Think about this :

- your bike should have low-profile tires

When the profile is too important (see picture) there will be a large energy loss due to vibrations. You will also have more noise when pedaling.

- the fixation of the axis should be not of the fast-release type

The fast-release-type with flat end (se picture) is often not compatible with the bike stands. You can easily change the axle with another (second hand) axle.