Sean Michael Ragan shows us how he built the Bike Phone Charger project that Alastair Bland wrote for Make magazine. It uses an interesting component construction inside a plastic housing. I think a great addition to this project would be cram a small USB battery system in the housing so that the system charges a battery so that it could be used when the bike is stationary.
“The charger circuit consists of a rectifier, a capacitor, and a voltage regulator. Â The rectifier contains four one-way electrical gates called diodes which, working together, convert the back-and-forth wiggling of the charges in AC to a series of DC charge pulses.
The large capacitor connected between the DC terminals of the rectifier smooths out these pulses, charging up when there’s more energy in the system and discharging when there’s less.
Finally, the voltage regulator holds the incoming DC power down at a steady 5V, which is what most cell phones and other mobile devices are designed to accept. Â Without the regulator in place, the charger might deliver more than 5V to your device, which could damage it.”
