Nixie Thermometer and Hygrometer With Arduino Nano

How to spend some time having fun and learning a lot on boost converters, one wire sensors, Nixie tubes, Arduino coding.

In this period we are all asked to stay at home to protect ourselves and others from the COVID-19. This is the best time to use some of our free time to make a cool project using the components we have in the boxes.

In this case, we are going to realize a Thermometer and Hygrometer.

Stay hungry, stay safe, have fun!

Let's start to assembly the boost converter. Few components, a super easy to find IC, a large prototype board.

The component placement can be done in a small portion of the board. Only 45x55mm are required.

For the electric connection, I use the wires coming from a 2.5mm cable. Easy to manage and robust. Where the current is high you can twist 2 or 3 together but for short connections like in this case, it is usually not necessary.

The Prototype boards can be used for a multilayer assembly with a small trick. This can produce even more compact assemblies.

Time to create the sockets for the ZM1000 nixie tubes and wire the BJTs used to control the tube anodes for the multiplexing. ZM1000 connector requires wild cabling in this prototype.

The IN19-A is a special alphanumeric nixies tube. Its long leads permit to be soldered directly on the board.

The Arduino board is connected through wires to the anode drivers. Mounting the board on sockets permits to compact more the circuit using the 3rd dimension. To drive the cathode a Russian K155ID1 IC has been used.

The final disposition of the components, everything is in 100x85mm.

The temperature sensor is a Dallas DS18B20. The humidity sensor is a DHT11.

The three LEDs are used to indicate when the temperature is below 0°C (Blue), between 0°C and 50°C (GREEN), and above 50°C but less than 150°C (RED).

The push-button is used to switch among different visualizations mode:

1. Temperature in °C;
2. Temperature in Kelvin;
3. Relative Humidity (%);
4. Shift between °C and Kelvin;
5. Shift between °C and Relative Humidity;
6. Shift between Kelvin and Relative Humidity;
7. Shift between °C, Kelvin, and Relative Humidity;

The Bar Graph provides the analogic reference of the measure.

The final result

The schematic, The BOM and the Arduino code.