We like POV(Persistence of Vision) projects – specially those with unique ways to transmit energy to the turning row of LEDs (Light Emitting Diodes).
This POV however beats the rest that we have seen so far – this one is a freakin weather station. Instead of displaying graphics this POV displays the current temperature and relative humidity. And the best thing we like about this guy? It generates its own energy!
It uses a stepper motor as a generator, when a stepper motor is turned current flow through its wires. It is then rectified using a set of diodes and stored into a 6 – capacitor charge bank. The Charged stored in the bank is then fed to a TPS5420 buck converter that outputs 3.5V – just enough to drive the ATmega88 microcontroller and the 8 – LED array. The ATmega88 is operating at 10MHz while it gathers humidity and temperature data from an SHT21 using I2C protocol. To sync when to start displaying, it uses a hall effect sensor from an old floppy drive - this is used to determine absolute position of the blades. Talk about renewable energy on weather forecasting!