- Mipwr cases connect to battery charging points on the iPhone 4, 4S and 5
- It contains a lever that when squeezed, produces an electrical charge
- This electricity is created by electromagnetic conduction inside the case
- Squeezing the lever for a minute produces around 30 seconds of charge
- Cases are expected to cost $25 (£15.50) if the firm secures enough funding
Forget wireless chargers, the latest way to extend the battery life of your phone is in the palm of your hand.
Mipwr Dynamo cases slide onto an iPhone's battery charging point and either store energy that can be used as a backup - adding two hours of extra charge - or contains a hidden lever that can be squeezed by hand to generate electricity.
Its Illinois-based inventors claim squeezing the lever produces electricity by electromagnetic conduction inside the case, and a minute of squeezing gives an extra 30 seconds of charge.