by Bob Coggeshall /

Mr. Coggeshall contacted my via the Facebook page to direct me to his website and I really wanted to show off his work.  (This is the first of two posts on his work.)

Mr. Coggeshall has developed a driver that can power up to seven B7971 tubes and is primarily driven by a computer.  One other feature that I have not seen elsewhere is that it establishes a serial connection over Bluetooth.  This enables the owner to place the device some distance from the computer without having to run cables.


Bluetooth B7971

from Cogwheel:


The Cogwheel model 301x  is a versatile Nixie tube clock driver board. Its features include

  • Drives tubes located on a separate board to accommodate a variety of tubes and custom enclosures.
  • Drive capability for up to 7 tubes with up to 14 cathodes each;
  • Supports classic “0 through 9” numeric tubes as well as large segmented alpha-numeric tubes such as the B7971.
  • Symbolic tubes and individual neon lights can also be driven.
  • Stable, modern design utilizing surface-mount components.


On board features include:

  • Flash-upgradeable processor (Microchip PIC16F877)
  • Non-volatile configuration memory
  • Adjustable high voltage generator fully controllable by processor.
  • Non-volatile clock chip (Dallas/Maxim DS1302) with capacitor backup for maintaining time for up to 12 hours across power outages.
  • RS232 Serial Interface – Can be interfaced to a GPS receiver, personal computer, or other device.
  • 1 pps (pulse per second) TTL level input for incrementing time from external source (GPS receiver or other equipment).
  • Cool-running 5 volt switching power regulator – Can supply up to 500ma of power to an external device such as a GPS receiver.
  • Infra-red receiver interfaced to a secondary processor (Microchip PIC12F675) for control
  • AC powerline frequency can be sampled by processor Runs on AC(9-12V) or DC(12-15V) power


Latest software release features include:

  • Complete Hours, Minutes, Seconds, Year, Month, Day timekeeping
  • Configuration via buttons, infra-red remote, or serial command interface
  • Configurable synchronization source - Non-volatile real-time clock, GPS, or serial
  • Configurable time increment source – Internal, 50/60 Hz AC Power, or 1 PPS input
  • Optional Daylight Saving Time Correction (North American rules)
  • Per-digit transition fading effect
  • Smooth transition between HHMMSS and YYMMDD displays
  • GPS – Display blinks if GPS does not have a fix
  • GMT offset to convert GPS time to local time

Be sure to check out his site for more information.


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