PORT-A-LIGHT

-PROBLEM-

In Sub-Saharan Africa, people lack reliable access to electricity which makes it difficult for households to have safe and affordable lighting at night. This project aims to develop a device that converts energy from bicycle riding into stored electrical energy that can power lights in homes after dark.

Functional Requirements:

After doing some research about the Sub-Saharan communities, I discovered that the main mode of transport was to bike. Therefore now I can relate converting energy from a bicycle to stored electrical energy. Some functional requirements for the project are:

1. Energy Capturing: Convert bicycle movement to energy

2. Energy Storage: Store energy for later use

3. Lighting: Use the battery for light output

4. Simple Interface: Low maintenance indicators for different battery status

5. Connection type: Easy to use and replace connection type between batter, generator and light

6. Portability: Must work with common bicycles and quick to install/remove

7. Cost: Must be low cost so that funding can result to more products and lower cost to purchase

Power Production Estimates:

Bicycle Roller Stand

The user would place their bike on the roller and then would ride which would power a chain system that runs a generator and would charge up their batteries.

Pros:

• No bike modifications

• Usable by multiple users

• Allow access to many people

• Low cost to be used for many people

ENERGY TRANSFER

DESIGN ASSUMPTIONS

To calculate the estimated power mechanical energy available from a bike rider, several assumptions were made with research for bike riders in rural areas.

Battery To Light Source Designs

Typical cycling distance: 5–15 km per day

Average cycling speed: 12–15 km/h

Average sustainable rider power: 50–100 W

Expected generator efficiency: 40–60%

Target lighting power: 3–6 W LED lights

A healthy adult can sustain roughly 100–150 watts of mechanical power via bicycle for an hour however due to the difficult terrain of the bike riders in Sub Saharan African, the expected mechanical power produced is more likely between 50-100W. Additionally, we assume the generator to have an efficiency of only 50% due to slipping, friction and other factors.

The energy produced for a 45 minute ride could be,

Therefore with the energy produced, a 5W light bulb could run for 5.6 hours which is enough to light up a house between sunset and bedtime.

I thought of 3 possible designs that could work for turning mechanical riding power into electricity.

From the 2 designs, both use an exposed LED light for easy maintenance and also angled so that the light can spread in a wider range. The first design above was my initial design thought where the portable sliding battery pack slides in at the top and powers the LED lights with a simple battery indicator. However this means that the light box will have to be placed lower which reduces the LED light spread. Therefore I thought of designing a 2 part system where a power box is connected to the light box. This allows for easier access to the battery pack and the LED lights will have a wider spread however reaching the LED light for maintenance will be more difficult.