I decided to continue on working on a bicycle helmet with an integrated communication unit and do not switch to a collar with the same functionality. Because in my opinion it is recommended to wear a helmet while cycling and maybe such a helmet would have the result that a few more people would wear a helmet.
ca. 10% of the German adults wear a helmet while cycling ca. 55% of the kids are wearing a helmet. Source: ADFC
Other products out there
During my ongoing research besides my experiments with a helmet and several headsets I came across two interesting products
Helmet with Beats by Dr Dre
the first one is a product from POC Sports. They created the Receptor + a helmet which “is developed for multi-disciplinary activities and is the only helmet in the world that has the appropriate certifications for skiing, snowboarding, biking, skateboarding and water sports.” Additional they offer the Communication Neckroll with which the user can equip his helmet with a Beats by Dr Dre ® headphones and microphone.
So far this is the most fashionable solution I have seen. But the helmet looks less like a regular cycling helmet and more like a snowboard or bmx-biking helmet. And the headphones look like as they cut off all the surrounding noises. These are two points I want to avoid with my helmet.
Buhel D06 communication system
Buhel offers a helmet communication system which is, according to them, a solution for many different activities, also for cycling. The bone-conduction microphone is designed to fix it on the chin strap of the helmet.
The integration of the bone-conduction microphone into the strap might be a good solution but I want to avoid in-ear headphones and work on another solution.
Beside my researches I am experiencing with a helmet and some little speakers and headphones to come up with a solution which works for listening to music and making calls while riding and take care about the surrounding traffic.