IN-9 Nixie Bargraph Thermometer with colour-illuminated scale
This glowing new bargraph thermometer from Elektor Labs is based on an Arduino Nano. It offers a beautiful graphical representation of ambient temperature using a Russian IN-9 tube and an illuminated scale with various RGB-controlled colours. The temperature scale in degrees Celsius as well as Fahrenheit extends from 10 °C to 30 °C / 50 °F to 85 °F. The circuit consists of a 5-to-150 V "voltage doubler" step-up converter, an IN-9 tube driver based on a low-voltage rail-to-rail opamp, two RGB LEDs and of course the Nano.