A simple yet powerful device which gives off-grid communities in India a reliable source of energy by harnessing their daily motion.

What is it?

Jhoule – a simple yet powerful device which gives off-grid communities in India a reliable source of energy by harnessing their daily motion.
Jhoule is a fusion of the English word for Joule (a unit of energy) and Jhool, the Hindi word for a swinging motion. Jhoule was born out of my interactions with the tribal communities which inhabit the region of Chhattisgarh, India: geographically remote settlements, negligible electricity supply and insurgent activities. Jhoule sits at the confluence of tradition and innovative product design.

How is it used?

How it is worn for charging:
Jhoule is a wearable device which, when hooked or strapped between the body frame and a moving limb (for example the waist and an ankle), harnesses the energy from the swinging action of the leg (for example, while walking) to drive a dynamo and charge the battery. The energy harvested during the day is stored and used to power the embedded LEDs, providing an additional 3-4 hours of light after the sun sets.

Use as a guiding light:
During one’s commute home, Jhoule can be strapped across their chest, and the light can be diffused and used as an indicator to make the user visible to oncoming traffic in the absence of streetlights, ensuring road safety.

Use as a task light:
At home, Jhoule can be suspended off of a nail in the wall and the LED can be used at its full brightness to allow children to study for longer, for food to be cooked in a hygienic manner, and the family to bond.

What technologies does it incorporate?

Jhoule uses the trigger of human motion to spin the shaft of a locally available DC motor for generating a voltage. The speed and duration of such spinning is directly linked to generating a higher intensity of voltage. Jhoule contains a circuit that is able to harness the uneven input current (resulting from different kinds of human movements) to charge a 2.4 Volt rechargeable battery.The circuit rectifies the alternating voltage from the DC motor and gives it a slight boost in order to charge the battery. A tiny LED indicator on the casing shows the charging status. An intuitive press-down button serves to turn on the battery in order to light up the embedded chip LEDs. As of now, one hour of walking generates enough to charge the battery to provide 4 hours of light.

How does it work?

Jhoule which can be worn between any two moving body parts (for instance, the lower back and an ankle or the waist and a wrist) such that the main device containing the motor and circuit is attached to the user’s body frame and the retractable string is pulled out and hooked onto a band worn on the user’s moving limb. If attached to the waist and ankle, the bending of the knee (whilst walking) extends and retracts the string, setting the connected internal gears into motion, hereby spinning the motor shaft, generating a voltage and charging the battery.

Who uses it?

Jhoule taps into the physically active lifestyle of the community as a source of energy; it can be worn by any or all members of the family, giving preference to members who walk and move around more. Their geographically dispersed layout of the villages in Chhattisgarh means that children walk at least 3-4 miles to school, most adults commute to larger neighboring villages for work, people walk to the community markets for food and make a daily trip or two to the communal water pumps to draw water for their household needs. During summer, they spend their days gathering forest produce and during the harvest season they work on agricultural fields. On average, every villager walks at least 8-10 miles on a daily basis.

Why does it help?

The World Bank’s report on rural electrification in developing countries states that the most dominant use of electricity in the rural household is for lighting, accounting for 80% of electric consumption. So in cases where such remote villages are connected to the grid, the load is concentrated in the evening reducing, the financial viability of having a grid connection. In such a situation an off-grid solution such as Jhoule, that involves “learning by doing” and can be manufactured and repaired by the locals themselves is more cost effective as well as easy to adapt into the lifestyle of the people. Keeping this in mind, Jhoule has been designed as a culturally organic product, to involve local communities into the product’s ecosystem.

During the day it adorns the user like an ornament, in the evening on their commute home it acts as a guiding light preventing road accidents in the absence of street lights. After sunset, at home, Jhoule provides a much needed safe, reliant and sufficient source of light. It also removes the need to travel long distance to pay electricity bills (as it is a one time purchase) or to lodge complaints (as it can be repaired locally).


Team's Location


Team's Occupation


Team Members

Yogita Agrawal

Focus Area(s)

Behavior Change

UNICEF Pillar(s)

Health, Education, Social Inclusion

These pages have been pulled directly from applications submitted to the Wearables for Good Challenge in 2015. They represent the work of the individual teams and have subsequently not been edited.


Write a Comment