What’s the temp in your house? This Arduino-based Nixie tube thermometer will tell you

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Because every engineer loves a good Nixie tube thermometer.

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If you want to know the temperature, normal digital thermometers, or increasingly the Internet, are usually good enough. Visually though, it’s hard to beat the warm glow and retro look of a Nixie tube. What better way to display this than with a three-digit tube display like Luca Dentella’s build.

His process is outlined in a series of 10 posts that can be found here, or you can just skip to the completed version. The “brain” of this display is a Arduino Pro Micro (ATmega32U4). It uses a thermistor-style temperature sensor, which has a resistance than changes depending on the temperature, to tell how hot it is.

The display is, of course, three nixie tubes. The first thing that’s interesting about the setup is that the third tube shows “°C.” Dentella is using an “IN-19A” tube for this purpose, which can also reveal a number of other symbols. In this case, it shows the degrees Celsius value at all times.

The other interesting part of this design, besides the generally clean layout and printed circuit board use, is that each tube has a programmable LED under it. This allows for a unique coloring, and could certainly have produce many interesting visual effects. Perhaps in another life, this type of display could serve as a sound level meter, with the LEDs pulsing on and off to the beat of the music.

 

The ATtiny1634 Nixie clock

A Nixie tube can best be described as an electronic device that displays numerals and other information using glow discharge. The glass tube is packed with a wire-mesh anode and multiple cathodes, shaped like numerals or other symbols.

Recently, a Reddit user by the name of “Smallscaleresearch” created a slick Nixie clock powered by Atmel’s ATTiny1634.

“I was digging around in my parts bins and came across most of the exotic bits required to build a GPS sync’d Nixie tube clock. Logic side is an ATTiny1634 with a surplus (old) SiRF GPS module. HV side is based on a surplus backlight inverter, rectified and filtered. At 3.3v it puts out around 140v under load, and around 270v if allowed to float,” the Reddit user explained.

“To switch the HV, I’m using a Supertex HV5122 high voltage shift register which gives me 32 channels. Since I only have 32, the high digit of the hour only has digits 1 and 2 connected, so to display ‘0’ I just leave it off. The 4 BS108 MOSFETs on the board are just level shifters for the control lines, since the HV5122 needs a minimum of around 10.5v for logic ‘high’ on its input.”

Additional information and schematics for the ATtiny1634-powered Nixie clock can be found here.

As previously discussed on Bits & Pieces, the high-performance Atmel picoPower 8-bit AVR RISC-basedATtiny1634 microcontroller features 16KB flash memory, 256B EEPROM, 1KB SRAM, 18 general purpose I/O lines, 32 general purpose working registers, one 8-bit timer/counter and one 16-bit timer/counter.

Additional key specs include two full duplex USARTs with start frame detection,  universal serial interface (USI), I2C slave, internal and external interrupts, a 12-channel 10-bit A/D converter, programmable watchdog timer with Ultra Low Power internal oscillator and four software selectable power saving modes (the device operates between 1.8-5.5 volts).