Leather Clutch with Inductive Charging

Project Brief

I collaborated with an artisanal leather designer to create a series of "smart" accessories that would incorporate wireless inductive charging for cell phones. My role involved designing a circuit that would be able to discreetly fit into a leather clutch while providing enough power to be able to fully charge a phone. These leather accessories would be featured in Milan Design Week.

Process

In order to design the circuit, we first needed to determine the various use cases of the clutch and the capacity of the battery needed to charge the phone.

The electronics within the clutch needed to:

Charge a lithium ion battery

Use the lithium ion battery to fully charge a phone through wireless inductive charging

Show how "full" the battery is

Add minimal bulk to the clutch

Given the above stipulations, we chose to design a custom battery with a manufacturer based in Shenzhen. The battery would be less than 2mm in thickness in order to add minimal bulk to the circuit. It's dimensions would be 100mm by 200mm in order to ensure that it had enough capacity to charge the phone.

The above image shows an initial design of the circuit. The inductive charging pad is connected to a Gemma M0, small microcontroller that is primarily used in designing interactive wearables. The Gemma M0 is connected to a three NeoPixel LED's that show how "full" the battery is. If it is full, then all three light up, if it has some power left, two light up and if it needs to be charged, then just one lights up.

Current Prototype

This image shows the state of the latest prototype with the proximate locations of each item and the customized lipo battery. There is a micro USB for charging at the left edge of the bag. The LEDs will go along the straps.

Next Steps