Friday, August 12, 2011

POV Clock

I found an interesting persistence of vision clock for a few dollars at a local thrift shop


Its a simple 8 led array on a thin piece of pcb held up by a spring with a magnet, a large coil pulls the array forward and the spring does the rest of the work, the base is a nice polished piece of aluminum... when running there is a surprising amount of rocking force so a heavy base makes sense

 

Other than showing the time there are a number of annoying messages, looks to be an easy thing to hack



It is controlled by an old Atmel AT87F52 microcontroller, an LM339 comparator for the break beam sensor (i think), 74hct244 to drive the leds and a 2k eeprom to store custom messages. A ksp2907 transistor drives the coil. I would like to replace the mcu with something more modern, with a proper RTC and communication, adding RSS feed capabilities and maybe changing the led color

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