Wristify – Wearable A/C on your wrist

Wristify_BraceletMotivated by the current heatwave most of Europe is suffering right now I wondered if there would be some sort of wearable, personal temperature regulating device, either a product but at least some ideas how to achieve that.

What came up during my search amazed me, a body temperature managing bracelet from a team of MIT students who looked at wearable, personal air-conditioning.

The bracelet is named Wristify, a thermoelectric bracelet to regulate, to a certain extent, the perceived temperature through heating or cooling.

Wristify makes use of the Peltier effect, a phenomenon that causes either heating or cooling when electrical current flows across junctions of two different conductors. Current that flows from one conductor to the other causes one side to heat up while the other side cools down. The current is supplied from a small battery incorporated into the wrist strap.

Why to cool or heat the wrist? The team studied the physiology of the human body in regard of perceived temperature sensitivity, meaning how we humans react to temperature changes in the context of well-feeling.

It turned out the wrist is one such place where this effect of perceived temperature sensitivity can be fully utilized.

The last but to me most innovative discovery was: the heating or cooling effect can be amplified when  heating or cooling is applied in pulses. As the team found out, our body quickly acclimates to a temperature, either very hot or very cold and this perceived cooling or heating quickly loses it’s effect.

Think about putting your hands in hot or (very) cold water. After a short while you will not perceive hot or cold as you did in the first few seconds.

Wristify changes the skin contact surface temperature at a rate of about 0.4 Celsius per second which is far more than the 0.1 degree Celsius research suggest is sufficient to generate a perceived heating or cooling effect. A very smart, wearable and personal air-condition on your Wrist(ify).

Sure it won’t get away with room A/C or oven but lowering the need for room cooling or heating would save quite some money. But most important, you can cool or heat-up yourself when out and about.

To my opinion, Wristify would be a interesting commercial product if it could be realized, meaning product in volume and the from factor suggested in the photo on the top.

The proof-of-concept prototype, shown below. Certainly not something anyone will ever strap on the wrist.


I have not found any update on Wristify since it’s first appearance in 2013 and unfortunately I have the feeling it will stay in the prototype stage of some time until technology can follow the aesthetic requirements for a fashionable, cool and hot wrist band.


  1. I guess they stopped the development, because the energy which is required would be too high for a small battery. I even have thinked about to make it, still have some peltier elements at home connecting to microcontroller which give pulses to the element over a transistor and a skin sensor to measure the body temperature. And to be honest, I don’t would care about to have a small lithium battery in my backpack 😉 ^^

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