This is a project for a Russian IN-13 bargraph Nixie tube to use it as an indoor room thermometer. It is named “NixieTherm” and is also available as a fully complete kit incl. enclosure as shown at www.Nixiekits.eu
The IN-13 is a special construct of a gas discharge Neon display and works similar to the well know Neon bulb in illuminated mains power switches or as Nixie tubes. But this bargraph has a current depending length of the glow. As all other cold discharge tubes also the IN-13 needs a “little bit more” high voltage to work; at least 120VDC. The current through the tube must be limited, normally with a resistor. In the NixieTherm this is done with a high voltage transistor, as we need a variable current from 0….4.5mA.
Analog IN-13 bargraph Nixie tube thermometer - [Link]
I’m really very happy to present this circuit! This is a very special page, and what’s special about it is that this circuit is designed NOT by me, but from a PCB Heaven reader, which happens to be also one of my students in my PIC classes. As a matter of fact, he is my first student… Well, ok, he is my only student :). So, this is the very first circuit page that i host in my site which is designed by a PCB Heaven reader. Special thanks to Panagioti Kalogeri, which you will find him trolling around my site with the id _Pike…
This circuit is the result of an exercise that i asked him to make, in order to practice with the Timer modules of the PIC. The PIC will read the tacho output of a PC fan. The rpm is then translated into a number of LEDs turned-on on the bar-graph. The minimum rpm during which only one LED is turned on is 600 rpm, and the maximum is 1200 – which is also the max speed of the fan. Panagiotis was asked to implement the rpm measurement with the Reverse Frequency Measuring as described here.
PC Fan RPM Bargraph Meter with PIC - [Link]
This project requires a basic IC operates as a linear voltmeter with a 1.2v range. The LM3914N to be used for this project.It is a chip specially designed to drive a bargraph display,using 10 leds as the scale. This project needs is to get full power showing all 10 leds lit, with just the bottom led lit when the fan controller is turned right down to around 6v. [via]
A bargraph display - [Link]
This Bargraph can be modified to run like a knight rider bar, or simply move a light from side to side, its up to you. The project is very simple, few parts involved, even if it contains a micro-controller, its still simple. The source code is written in C and can be compiled using GNU C WINAVR compiler. [via]
Bargraph 101 LED display - [Link]