A Rechargeable Helmet Light

Last year, electronics maker “Quiescent Current” purchased a new helmet to make bike rides a bit safer. This hemet is an ABUS Hyban 2.0 model, which comes equipped with an integrated LED light array on its back. While this feature certainly would make one more visible at night, it has a few drawbacks, including what Quiescent Current describes as misaligned LEDs and a single CR2032 coin cell that provides a limited amount of power.

The solution, of course, was to create an enhanced PCB that drops in as a replacement for the stock lighting electronics. The new board has six nicely arranged LEDs, along with a micro USB connector for recharging a LiPo battery. A TP4056-based battery management solution protects the battery from under/overvoltage as well as short circuit and temperature limit conditions, important for a safety device that resides next to one’s head.

For control, an ATtiny10 microcontroller takes care of flashing different patterns, and the system is activated by a simple pushbutton. Depending on the run mode, the light can illuminate for two hours when fully on, or up to around 65 hours in the lowest power blinking setting. Standby time is calculated at 1.5 million hours – so unlimited for all practical purposes.

You can see a short demo of the device in the video below, and design files can be found on GitHub. It’s also available for purchase on Tindie.