You know the feeling-you have taken the occasional rock or ice chunk to the head or had a couple of nasty falls on your mountain bike but don't want to get a new helmet without knowing for sure the old one is toast. Well now you will be able to know for certain if it is necessary to replace your helmet with a new process that causes stinky oils to seep out of plastic materials when they are damaged.
Only completely damage-free helmets do the job of protecting your head properly. Normally it is recommended that you buy a new helmet after a certain period of time but it is hard to throw away a perfectly good helmet and spend money on a new one.
Developed by research scientists at the Fraunhofer Institute in Germany, a new helmet making process produces polymer materials or plastics that start to smell if they develop small cracks. Large cracks will really cause a stink.
The smell comes from stinky oils enclosed in microcapsules, measuring just 1 to 50 micrometers, which break if cracked. A layer of melamine formaldehyde resin encloses the capsules so that they are completely airtight and mechanically sealed until broken.
The capsules will open and exude the stinky substance at a level according to the amount of damage, as a sort of warning indicator. This means you will know you need to change out your helmet way before the damage gets outside of the recommended safety range for failing.
The microcapsules are inserted in a thick foil made of polypropylene, which is fastened to the head gear. So now you know if you are intentionally dropped on your morning ride or can't find a belay partner anymore, it is probably time for a new helmet.
When will we see this being picked up by Petzl, Black Diamond and others for their climbing/caving helmets?
Source: The Gear Caster (Under Creative Commons License: Attribution Share Alike)