IN-8 Nixie Clock
(This project is still under development, more information will follow)
Overview
The nixie clock features six IN-8 tubes fitted in sockets. The clock is controlled by a Atmel microcontroller and is packed with features. It is powered from a low voltage plug in adapter and uses a simple boost converter cicuit to generate the high voltage necessary for the tubes. A real-time clock is used to keep the time and is backup powered by a supercap when the clock is off. High power blue led are fitted under the tubes and can be dimmed in groups of two by pwm.
The clock is direct driven, that means every tube is connected to its own driver. These are Russian K155ID1 drivers specialy designed to drive nixie tubes. They are old and limited avaible, but work great. It definitely ads to the "vintage" feeling. Other benefits of direct drive are that all tubes have a constant supply and light at the same time. This means, no high peak currents during switching, no switching noise and tubes can achieve a higher brightness then multiplexed tubes.
Features (Hardware)
- 6x IN-8 nixie tube fitted in socket
- Supercap instead of backup battery
- Direct driven by 6 K155ID1 drivers (the Russian equivalent of the 74141N)
- PWM driven blue led's under tubes
- DS1307 serial real-time clock
- ATmega328 microcontroller running with Arduino bootloader
- Simple 9V to 180V boost converter using the legendary 555 as controller
- Cathode poisoning prevention by programmable effects
- Three tactile buttons for user input
- Temperature sensor
- Buzzer for alarm function
- On/Off switch
- Power supplied from a low voltage plug in adapter 9V DC
- Single compact PCB, only 75 x 160 mm
Schematic
Images
Close-up of the tubes
Another close-up
Clock in full daylight