Monthly Archives: March 2018

ИГГ1-64/64M Adventure

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It appends I spend a bit of time on eBay looking for uncommon or old displays such as the famous Nixie tubes. Large matrix displays emerge some time ago maybe due to the discover of an old stock. However, I never found someone using them, for a good reason. Around 360 Volts is needed to light up a pixel.

Gazotron

gazotronGazotron, or Газотрон is (or was) an Ukrainian electronic tube manufacturer (do not confuse with Gas-o-tron). It’s not easy to find information about this company, even gazotron.com is closed. But actually there is still plenty of their products available if you would like to buy electronic tubes, such as IN4-nixie tubes. The logo is dot inside a circle.

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They made in the 90’s different sort of dot matrix panels. They are quite large, 19x19cm, and for the moment I saw 3 kind of pixel composition. A 32×32 matrix, all pixels are green. A 64×64 matrix, pixels alternating green and red, and finally a 64×64 matrix with red-green-blue alternating pixels.

I bought one green-red some time ago, and recently saw a page on hackaday.io that revive my interest.

Seek for information

The short datasheet provided with the screens (shown in the mentioned page) explains the voltage values needed to light up the pixels as well as the timings, but it does not help to find a way to generate these high voltage signals.

My research on internet first leads me to this Youtube video demonstrating a 8×8 pixel drive, and a quick view of the breadboard circuit. Then I start to find forums written in Russian where someone manage to drive the all 32×32 matrix.

And finally, a piece of a datasheet showing a circuit example able to generate the ~400 Volts anode signal from a 200 Volts source.

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Test Drive

I reproduced the circuit on a breadboard as well, using a 180V ‘nixie’ power supply.

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Motivated by this success, I started Kicad and designed a PCB. I Selected SMT components in order to reduce the size of the 64 anode drivers and the 64 cathode drivers. The board arrived as perfect as usual with OSHPark.

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And they are working!

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Cabling and soldering

There is 92 components and 34 wires on each of the 8 boards to solder. As I don’t own a air soldering station, I did everything with a good iron and solid patience.

But it was worth the effort, they all work great.

Interface

I used the same micro-controller as the BIG_CLOCK to talk with the high voltage boards. Especially because it has at least the 32 outputs needed. To interface this controller with the outside world and being able to display some useful pictures, I used the serial port.

I could then make a tiny Java program that copy part of the computer screen and send it to the serial port.

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Fun with Pixel Dust

I was quite amazed by the code demonstrated on a 64×64 led matrix by Adafruit (https://www.adafruit.com/product/3649). So why not trying this on the IGG1 display?

I have a MPU-9250 IMU and a raspberry-pi zero. However I need to adapt the code for this accelerometer, and send the data to the screen with the serial port. I’m more comfortable with Java than C or python, then I translate the code from Adafruit in Java.

To conclude

The full story and details are on the hackaday.io page here:

https://hackaday.io/project/46302-1-64x64m-adventure

Sources and schematics are on the following github repository:

https://github.com/pierre-muth/IGG_-64x64M

It was really a good time see this screen getting back to life, now it needs a purpose such as a weather forecast display or a nice clock. A lot is possible with the raspberry pi, including the use of the PIR sensor to only turn on the screen when someone is around…

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Anti-Proton Decelerator quick tour

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IMG_5399I recently wrote a project page about re-purposing a flip-dot bus display for the Anti-proton Decelerator control-room. It maybe interesting to show you with pictures how this synchrotron looks like.

The Anti-proton Decelerator (AD) is a 182 meter long synchrotron. Its aim is to lower the energy of anti-protons. In contrary of the majority of the existing synchrotrons, the AD is used as a decelerator, producing low energy anti-proton and send them to different experiments. For the details, have a look on the official web page.

The AD stands inside a concrete tunnel build inside a large hall:

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Before accessing the synchrotron ring, we can make a quick stop by the AD control-room (ACR):

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The hall with the concrete shielding is conveniently visible from the ACR:

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Down in the hall, we can find the access system for the machine tunnel:

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This special door will control your personal dosimeter and your identity with an iris scanner:

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Once in the ring tunnel, you’ll meet the AD itself. Here we are facing two of the main dipole magnets (in blue):

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And right after we can see the vacuum pipe going through quadrupole magnets (focusing elements, in red):

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On the next picture you will see on the right where the anti-protons come from. Behind the wall is the target and horn area. On the left starts the injection region where we can see the vacuum pipe literally going through the blue dipole yoke:

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In the next strait section we will meet the electron cooler, one of the rare device able to reduce the size of a charged particles beam:

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Right after, these two big silver colored blocks are radio-frequency (RF) cavities. In general RF cavities are used in synchrotron to change (increase or decrease) the particle beam energy. These two ones are used in the AD to change the shape of the beam:

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Continuing along the ring you’ll meet a lot of magnets to steer and focus the beam:

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The stochastic cooling system is another remarquable element of the AD, it is a beam size reduction system:

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Without entering into the details it consists of beam sensors and fast kicker elements (electro-static). The sensors signal is amplified and transmitted to the kicker elements that are installed at the opposite side of the ring. The transmission is faster than the particles take to make half a turn of the synchrotron.

If we exit the ring tunnel, we can pass by the stochastic cooling amplifiers:

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And the powering system for the injection element, able to deliver a controlled pulse of hundreds of kilo-volts. Most noticeably are the cable coils (Pulse Forming Network):

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I hope you enjoy this little tour, and thank you for reading.

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