spectura the junkromancer

I’m building an ultra high vacuum system, and have been accruing parts over time. I just recently wrote my first arduino program, a program that takes the voltage from the gauge, and converts it to a pressure reading in torr via a logarithmic scale equation.

The code is quite simple, thanks to the help of PaulRB and the fantastic arduino community forums!

#include <LiquidCrystal.h> #include <math.h> // initialize the library with the numbers of the interface pins LiquidCrystal lcd(12, 11, 5, 4, 3, 2); // the setup routine runs once when you press reset:    void setup() {      // initialize serial communication at 9600 bits per second:      Serial.begin(9600);      pinMode(A0, INPUT);              //A0 is set as input      #define PRESSURE_SENSOR A0;            lcd.begin(16, 2);      lcd.print("MKS  Instruments");      lcd.setCursor(0, 1);      lcd.print("IMT Cold Cathode");      delay(6500);      lcd.clear();      lcd.print("Gauge Pressure:");          } // the loop routine runs over and over again forever:      void loop() {      float v = analogRead(A0);        //v is input voltage set as floating point unit on analogRead      v = v * 10.0 / 1024;             //v is 0-5v divider voltage measured from 0 to 1024 calculated to 0v to 10v scale      float p = pow(10, v - 11.000);   //p is pressure in torr, which is represented by k in the equation [P=10^(v-k)] which is-                                       // -11.000 (K  = 11.000 for Torr, 10.875 for mbar, 8.000 for microns, 8.875 for Pascal)       Serial.print(v);       char pressureE[8];       dtostre(p, pressureE, 1, 0);        // scientific format with 1 decimal places             lcd.setCursor(0, 1);       lcd.print(pressureE);       lcd.print(" Torr");    }

The code simply sets A0 as a floating point unit for voltage, which is 0-5v from the voltage divider. Then it is calculated back up to a 10v scale and interpolated using an equation based on the voltage/pressure table provided by the manufacturer.

The equation is P=10^(v-k) where p is pressure, v is voltage on a 10v scale and k is the unit, in this case torr, represented by 11.000. It calculates that in floating point, then displays it on an LCD screen in scientific notation using dtostre.

I saw this interesting picture today on a website for credulous fools on how NASA apparently fakes mars images by modifying images of Greenland..

http://beforeitsnews.com/alternative/2018/03/nasa-film-crew-caught-behind-rocks-filming-rover-in-mars-like-devon-island-greenland-3600935.html

Now, I called bullshit immediatley on this, as it looks quite obvious someone not related to nasa photoshopped the image on the right, as the image on the left cannot be found on any official nasa sites. However, you can see a part of a metal boom on the rover.

The metal antenna boom is not from curiosity, but if you look at pictures of the opportunity/spirit rover you can see it is the tip of the low gain antenna. You can also see a white blanket with black cross hatching, this is the original landing blanket when the rover first landed, seen below.

however, no images of the initial opportunity landing match the angle and color, so I then looked for images from spirit, opportunity’s now nonfunctional sister rover. Once I knew it wasn't opportunity, it only took a few minutes to find the original NASA image the superimposed rover was ripped from.

Original NASA image:

So, just to compare. Below is the non-nasa fake:

A finished museum-quality recreation of the Mysterium Xarxes as of 4E 201

I learn in many ways, but actually doing physical projects that require me to expand my abilities teach me the most. I took interest in this project some years ago after seeing a video of Ben Krasnow’s on an ultra high vacuum system used for an electron microscope which he has also used for DIY sputter coating to make conductive glass. This project was very far outside my realm of possibilities and experience at the time, so I decided to start my own project from the ground up, engineer every part and work out every issue on my own to expand my knowledge of engineering and science. You don’t just learn from the research I want to do with this project, you learn so much about engineering which you can apply to other parts of your life.

Other people have done projects like this before, but I want to do this as professionally as possible, as if I was doing this in a university setting, so I can learn as much as possible, on a very meager budget.

This project is intended for multiple uses, and is designed to be partially modular to enable a variety of experiments to be carried out. The first proof of concept experiment of this system will be a Farnsworth Hirsch Fusor. This system will be able to achieve a very high level of vacuum capable of making a very functional fusor. The Vacuum chamber’s upper window will be exchangeable to set it up for different experiments, for example, when set up as a fusor there will be a high voltage feedthrough in the upper window for the inner grid and Deuterium gas backfill.

Another use for this project could be for coating glass with metal via the sputtering process to create DIY LCD panels. Creating thin film transistors, or partially silvered and fully silvered first surface mirrors for use in laser systems.

 This Ultra high vacuum system utilizes a retired 4 inch water cooled Daia DPF-4z oil diffusion pump and 2 stage rotary vane pump to achieve very high levels of vacuum. The Diffusion pump is majorly overkill for this project, but it was found for a great deal on ebay, and was impossible to pass up.

The Rotary vane pump is a harbor freight special pump, made by US general. It isn’t the highest quality pump, but it will be operated relatively rarely, and only used to pump air, and not refrigerants as it was originally intended.

A Varian 841 vacuum Ionization gauge was acquired on ebay for a small price is questionable condition, with the intention of repair as sub small project. Repairing old equipment like this and integrating into your designs are a great way to learn about how to fix electronic devices and engineer your own!

The actual vacuum chamber is a CF flanged tube from a larger system also acquired from ebay, but as we do not need a large chamber volume, this small chamber will work perfectly.

There is also a cooling system for the pump, various electrical work, an adapter plate that needed to be machined to interface the pump to the standard CF flange chamber.

The most integral part of this system is the diffusion pump, used to increase vacuum levels farther than mechanical means can achieve. A roughing pump, the US General rotary vane pump pulls the initial rough vacuum needed in the chamber and the diffusion pump, and the diffusion pump then activates as the second stage, increasing to the final vacuum level.

This specific diffusion pump operates on the oil diffusion principle for gas molecule removal, by which in the bottom of the diffusion pump, oil is boiled and vapor travels up the chimney, and the vapor is ejected out to capture as many gas molecules as possible, and fired downwards towards the outlet of the pump to carry the gas to the mechanical vacuum pump. Now, we do not want this oil splashing into the main chamber, so there is a liquid cooled baffle used to cool and condense the oil before it can get into the chamber.

To mate this Japanese made pump to the standard CF flange chamber, I needed to engineer an adapter plate out of aluminum. I used a CNC machine to mill out a plate of MIC-6 toolplate to keep a perfectly flat surface, as the o-ring mating surface needs to be perfectly flat, while supporting the weight of the pump and chamber.

The system after being adapted then needs to be mated, the pump head has an o-ring groove for sealing against the bottom of the plate, and the plate has a groove machined to seal against the bottom of the vacuum chamber. High vacuum grease is used to properly seal the o-rings against the mating surfaces. The diffusion pump then had its outlet tube modified to connect to the roughing pump.

This diffusion pump is large, and subsequently liquid cooled, so a water cooling system must be utilized. I made a water cooling loop by modifying and reusing an old office water cooler, and adding a pump and cooling lines to connect up with the diffusion pump. This water cooler has a stainless steel bucket that contains the liquid, in this case methanol, with the copper refrigerant coils wrapped around it, and a ceramic pump that pumps the cooled liquid around water jacket of the diffusion pump, and then returns it to the bucket to be cooled again.

The water cooler was picked up from its way to the dump, and was modified in the following ways, the entire cooler was shortened to half its height by folding the coils over on the back of the unit, and the entire system was cut in half, removing the water filter unit. A small water pump from eBay was installed, and plumbed into the system. The electrical system was then modified to power the pump when the cooling is on, and the thermostat turned down to prevent overcooling.