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

(see below in the instructions to learn more about the material)


- wood or metalworking tools

- soldering material

- 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 will be pedaling on your ordinary bicycle 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.

Material :

- touch-safe connectors with locking



Instructions :

- 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.

The PPP device will charge your computer in stead of the adapter. Cut the cable in between the adapter and the computer plug. Solder/screw the new plugs to the cut wires, female tot the adapter side, male to the computer plug side.

You can also chose to buy a new computer plug separately and assemble a new cable for the PPP device.

Step 4 - Energy monitoring

We will be monitoring the power and energy production of the device.


Follow the rules :

- don't overcharge your computer.

When you are approaching 100% charge you should be extremely careful to not put too much power. The current must AT ALL TIMES stay lower than the current indicated on your adapter.

- don't blow up the converter.

Again when you approach full charge be careful to not put too much power. The voltage should AT ALL TIMES stay lower than the 40V that is indicated on the converter.

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.