Rear-end collision! Uwe Pfeifer has often been rear-ended by other bikers in unfamiliar terrain, due to high speeds and sudden emergency braking. A brake light should provide a remedy. With success.
Here is Uwe's home-made brake light.
"I dismantled an old bicycle speedometer. I used the speed sensor as a magnetic switch and attached it to the handlebars. With the SRAM X.O shifters, it worked perfectly with double-sided adhesive tape."
"I glued a strong magnet to the lower part of the brake lever with hot glue."
"The brake light is a 12-volt LED from a scooter accessory (about 5 euros). I then attached the LED to a discarded cat's eye holder for the seat post. A 9 volt block battery serves as the power supply. The battery is completely sufficient for the power supply."
"I fixed the battery under the saddle between the seat stays with cable ties and insulating tape. The magnetic switch, battery and LED are connected in series with loudspeaker cables. I sealed the soldered connections against moisture and dirt with heat-shrink tubing."
And this is how it works:
When the brake lever is actuated, the magnet approaches the magnetic switch from the old speedometer. The switch closes the circuit and the LED lights up. When the brake lever is released, the magnet moves away from the switch and the circuit is interrupted. The LED goes out.
"In the forest, the LED is very bright, has a low weight and the power consumption is so low that the LED would light up for around twelve hours at a time."
