Patented: how LogCase draws without a battery

LogCase has no battery. Every picture on its E-Paper is drawn with a little energy borrowed from your iPhone, through the same NFC field used for contactless payments. The way we make that work is now protected by Japanese Patent No. 7901397.

The challenge

An iPhone's NFC field gives a small device only a trickle of power. Receiving an image and refreshing an E-Paper display both need energy, and doing both at once can leave too little for either.

Our approach, in three ideas

1. Receive and charge at the same time

While the image arrives from the LogCase app, the case also stores energy from the phone's field.

2. Pause, then draw

Once the image is in, communication is paused on purpose. The display is then driven from the stored energy alone, so all of it goes into drawing the picture.

3. Keep the transfer short

The image is packed to match the number of colours the panel can show. Less data means a shorter cast, and less energy to collect.

What it means for you

Press Cast in the app, wait a moment, and the picture changes. No charging, no cable, and the image stays without any power until you choose a new one.

The same technology can power other products too. If you are building something that should run without a battery, talk to us.