One of my biggest projects with the lab was building a closed-loop ethanol chilled -80 C thermal shroud and beam dump. This project was quite an undertaking and worth its own page and write-up, but one of the fun smaller side projects for this was building a thermocouple (TC) system and reader to measure the cooling performance at various locations in the flow system and on the beam dump and shroud. 

I specced the system to use type T TCs since they are capable of reading the -180 C temperatures we might see if we run LN2 through the system -- it's capable of running open loop LN2 but will normally run -80 C ethanol. After figuring out the minimum number of TCs needed both inside and outside the chamber, I ordered the TCs along with a type T TC feedthrough with the right number of ports and the right number of TC reader boards. I used Adafruit's MAX31856 universal TC breakout board since it supports type T TCs and has excellent documentation and an existing library for Arduino. 

With the hardware ordered, I wanted to come up with an intuitive way of visualizing the system and temperatures simultaneously. I sketched out some simple iconography representing the shroud, beam dump, and cryosails and then created a simple layout connecting each component that represented the flow through the system. I down-scaled the sketch to the display size I was using and used that as a template for reconstructing the diagram on the display using graphics primitives from Adafruit's (also excellent) GFX Library. I chose primatives instead of a static image of a sketch for the diagram for memory efficiency and also editability. If I wanted to change the diagram slightly, I could change the primative in code and reflash the Arduino. If I had used an image instead, I would have to edit the image in draw.io, export and convert to .bmp, save the .bmp image into the Arduino project code directory, and reflash the Arduino anyways. This would make updating quite tedious! 

Once the hardware arrived, I set about soldering all the common power and SPI lines to the 7 breakout boards together so there would be fewer connections to the Arduino. Since this was SPI and my first iteration, I did have 8 chip select lines (the extra is for the display) running to the Arduino that ate up a fair bit of IO. For the second iteration, I added a serial-in, parallel-out shift register to de-mux the chip selects from the Arduino into individual lines (this involved a crazy amount of debugging you can find in this Easter egg secret webpage). On the arduino, the 7 IO pins are reduced down to 2 IO pins running to the shift register (clock and data in). Although I don't anticipate needing any new IO to the Arduino, it never hurts to have extra free pins, and it was fun playing with a shift register for the first time!

All EP research requires high-purity gas delivery to usually a cathode and anode. In the case of SPACE Lab, some of our advanced concepts (the AC in the lab's acronym) require the delivery of multiple gases simultaneously. To the left is the P&ID and picture of the system I built for our large vacuum chamber. Two mass flow controllers (MFCs) can independently or jointly supply up to 600 total sccm of gas to up to two delivery vacuum feedthroughs. A needle valve in parallel with the MFCs proves extra flow in the case of starting a thruster on air or N2 (which tend to be notoriously difficult to start at lower flow rates) or for quickly vacuuming out the entire manifolds when swapping gases to maintain high purity. 

Another special feature of the system is the teed section in the fix volume release area to increase the releasable volume for some systems (i.e. difficult to light cathodes).

Academic research labs tend to store most of their institutional knowledge within the heads of their grad students. Unfortunately, I and the newer grad students in my lab are not mind readers, and after an inter-lab confusion with a knowledgeable grad student, we decided to start creating simple, yet essential guides for some of our most commonly used equipment, our vacuum chambers. 

On the left is one of the guides I made for one of our chambers. While these guides aren't meant to teach someone who has never set foot in our lab how to pump down our chambers, they serve as a check list for lab members who have already been taught without having to ask another lab member or guess a step or a specific pressure where something cannot be operated. Another benefit is that writing down the steps ensures there's a safe, acceptable way of performing the operations. In the past, non-standard procedures, spread through word of mouth, resulted in close calls or damage to very expensive scientific equipment.