Balancing a healthy amount of time in the sun while avoiding overexposure to its harmful UV rays can be a a difficult task. Indeed, the challenge of finding this happy medium has produced a bevy of of UV-detecting wristbands, such as the UVeBand and the UVA+Sunfriend. Smartsun is the latest to join the ranks of such devices, alerting users to dangerous levels of UV exposure by changing color from yellow to pink when it's time to head indoors.

Though it has just made it to market, the Smartsun UV monitor has been some time in the making, having undergone two years of testing and development at Scotland's University of Strathclyde. It was here that its inventors, Professor Andrew Mills and Dr Michael McFarlane, developed the device and the chemical reaction that causes it to change color as it detects ultraviolet light.

The Smartsun band is designed for a single use, each beginning its life a yellow color, then shifting to a beige when approaching the UV threshold and, finally, becoming a fleshy pink when you need to cover up.

What causes this transformation is an acid-release agent that reacts to the levels of ultraviolet light. This in turn affects the pH levels in the material, causing a dye to respond and trigger the change in color. The company says that if applying sunscreen to your skin, it should also be applied to the band, as the levels of protection will be better aligned and it will take longer to change color as a result.

Smartsun has been taken from the lab-testing to the marketplace by Intellego Technologies, with packs of seven bands available for £6.99 (around US$12) apiece.