This is a helmet with a 3 x rgb led speed indicator.
The speed is shown by color coded numbers 0-9 (from red to green to blue to violett - that would be 0 - 3 - 7 - 9 and with the numbers/colors in between).
The information of the momentary speed is acquired from a new'ish GPS/GOLNASS/GALIELEO/QZSS & SBAS satellite receiver.
One 18650 LiPo gives the power for this system.
This is a quite old project and it did not work with a neo-6m receiver.
Now i'll test it and find out if its any good or practical - stay tuned!