Glass Clock #3 is designed to show off the Nixie tubes, from the clear glass/acrylic material to the round design elements that mimic the tubes. Surface mount circuit parts are used on the custom black circuit board, shrinking the size to emphasize the Nixie tubes and downplay the modern circuitry.

Nixie Tube Clock #3 Large is the larger IN-14 and IN-8-2 tube versions of the Glass Nixie Clock. The IN-14 & IN-8-2 tubes have a 18mm digit height.

This view shows the different displays on the clock. Time, date, and room temperature can be displayed on the clock.

The different displays alternate, with time first, followed by date then temperature.

All three can be selected, or Time/Date or Time/Temperature.

Features:

• Optically pure Simax brand glass tubes for the case
• Time can be displayed in either 12 or 24-hour, leading 0 or blank
• Temperature can optionally be displayed in either Deg F, C
• Auto display brightness settings using light sensor
• Available crossfade, slot machine effect and digit slide effects for digits
• Nixie tube anti-cathode protection software
• Temperature compensated high accuracy Quartz Watch Crystal controlled time base
• Atomic clock calibrated for high accuracy
• Tube socket now standard on both versions - easy to replace tubes, no soldering!
• IN-14 version has fine grid tube option (rare IN-14fg tubes)

Images of both versions, one is the IN-14 tube version, the other is IN-8-2 tube version. Both tubes use 18mm high digits. The glass envelope is longer on the IN-14 tube.

One interesting feature of the IN-14 is the '5' digit. It is actually the '2' digit upside down and reversed, making for a very unique looking '5'. The IN-8-2 has a normal '5'.

The IN-8-2 tubes are more expensive than the IN-14's, and give a different look to the Glass Clock.

Also, the colons used in the IN-14 clock are Russian IN-3's. The IN-8-2 version uses NE2-A9A neon bulbs. Also, tube socket pins are standard on the IN-8-2 clock.

The tubes used in this clock are Russian (Soviet) military tubes. The Soviets, seeing the Western Nixie, came up with their own versions with similar sizes and shapes. Unlike the U.S. Tubes they were manufactured well into the 1980's.

Since the collapse of the Soviet Union, these tubes became available on the surplus market. This clock contains the IN-14 series or IN-8-2 series of tubes.

The tubes are long life tubes that have flying leads. These leads are soldered directly to the board for a trouble-free connection to the circuitry.

Tubes are warranties for 1 year from date of purchase, not including breakage or misuse.

The heart of the clock is a single circuit board that contains the high voltage power supply, processor, temperature & light sensors, and the Nixie tubes themselves.

The processor is a very low power RISC based AVR chip. Surface mount components are also used to save space.

A watch crystal is used to generate the timing frequency for the clock. It is temperature compensated for higher accuracy.

How it works

The Nixie tube anodes are supplied with 180v from a switching power supply. The tubes are multiplexed 2x3 (2 are on at anytime, with 3 groups of 2), using a pair of MPSA42/MPSA92 transistors. The cathodes are driven with a HV5812 Supertex chip normally used for fluorescent displays.

The AVR ATMEGA168PA processor runs at 8 Mhz with a 32khz watch crystal for the timebase. A MPC9700A temperature sensor is used to display temperature and also to temperature compensate the timebase in software.

Also, a light sensor is included for the auto brightness feature.