VFD tube counter v0.2

Blog ยป VFD tube counter v0.2

Posted on 1289161688|%A: %d %B, %Y|agohover

vfd_counter_v2.jpeg

I have a new build of the VFD tube email counter which improves several aspects of the original:

  • replaced atmega8 microcontroller with smaller attiny2313
  • replaced IRF730 power mosfet with smaller IRFD110
  • replaced $20 FTDI USB-serial cable with $2 PL2303 cable
  • replaced boring old white breadboard with fancy new transparent breadboard
  • replaced ugly breadboard wires with shiny magwire

However, by far the biggest change is the elimination of 7 transistors. The first design used the conventional high-side switch arrangement of a level-shifting NPN to switch a PNP driving each segment anode, but it bothered me that Jon Stanley was able to get his single-tube clock working without the level-shifting NPNs. Now, Jon's clock is operating at a lower voltage than mine, and he's using a PIC instead of an AVR, so I wasn't sure if I could make that work. It seems that compensating for the higher voltage with a bigger base resistor works just fine so far.

If it continues to work well, I'll put it on a circuit board and make a nice aluminum case for it, like this one.

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