Christina Holman | Design Blog

16-Channel Simulation Circuit Yesterday, we received both the package of multiplexers and eval boards and the package from Adafruit  with the PCB boards. In the lab we are currently wrapping up the divider circuit to simulate the mux signals, using 15 resistors, female pin headers, a SMA cable connector and a ribbon cable connector (left). Once we solder everything to the board as needed and test for the signal sounds with an oscilloscope, we can actually try to mount the discrete logic pieces to the PCB board and look at the muxes. Packages of Electronics However, to ensure that these muxes are completely compatible with the whole configuration, I have to create voltage diagrams and timing diagrams. The original mod16 binary counter would not work with the decoder or muxes due to different specifications. I found another 4-bit, synchronous counter that used the same voltage levels for High/Low signals (except for one scenario that we are looking into). Now u...

Today was the Plum Island Field Trip and the entire lab took the day off it seems. Yet, that doesn't mean we stop working on our practice presentations for tomorrow or anything else. Between the relaxation periods and the tutor training, I was able to finally email Mr. Knowles the part list for the gyroscope as I kept forgetting. I also finished up a first draft of the PowerPoint presentation (below): I tried to use the CRAP tool (Contrast, Repetition, Alignment, Proximity) in designing my presentation in addition to the advice from Professors Diesl and Conway from the workshop last week. I tried to make each slide as comprehensible in the simplest way possible and rely a lot more on speaker notes and discussion for explanation. First draft came out okay but there's always room for improvement.

During my free time today, I sat beside the water under the shade and read peacefully while listening to jazz music from my phone. It was simply wonderful, but what made it was a great book: Moonwalking with Einstein: The Art and Science of Remembering Everything  by Joshua Foer. When I first picked up this novel, I thought it to be a discussion of how the brain works and why -- or, in some capacity, dealing with Einstein's intellectual abilities. In fact, it is about Josh Foer's discovery of the mental elite or "Mental Athletes" -- those who have trained themselves in the art of memory. I honestly had to think for a while on the idea of memorization as an "art." Nonetheless, I kept reading. To be clear, Moonwalking with Einstein is not  a self-help guide to improving one's memory; the first four chapters are solely about his discovery of the possibility of "remember everything" and some of the scientific literature  and stories surroundin...

After a telephone conference between Prof. Battat, Dr. Phillips and I on Tuesday morning, I had a list of items to do and look into, (in addition to preparing my first presentation next week): Design a signal generator system to test multiplexer system (series of dividers) Design buffer amplifiers given a resistance of 50 Ω  and a load resistance of 2k Ω Read into the evaluation board manual for the Cyclone 5 FPGA (and prepare to program) I set off first to update my design of the multiplexer configuration with a 2-to-4 line decoder/demultiplexer as the logic system for SDs and a mod16 binary counter for the input lines (A0 and A1). We were about to go full circle on the counter system, back to the 4-input design I was working on, but this is absolutely simpler. In working on the signal generator system as a simulation of the 16-channel mux configuration, I started with a solderless breadboard to test different series of resistances with a battery pack. After t...

After reading through the papers that Prof. Battat handed to me in regards to his 2-bit counter, I finally understood how this design would connect to the overall 4 x (4:1) config and set out to design. However, the more I drew, the more I realized the less I actually understood. So, I put the schematic on hold and re-directed my attention until Prof. Battat returned. Eventually, I met with him and asked him about how A0 and A1 would connect in replacement of the 4 inputs planned for the 4-bit gray code counter. After a mini lesson in op-amps and gain control, I finally started drawing a more cohesive diagram that ended up like (upper-left) Machine Project: Plan B During my wait for Battat's help, it was just my luck that the machinist Mr. Knowles had sent me an email about not being able to make the Ships Wheel or  the Marine Desk Lamp. I went down to speak with him about potential projects, but neither a meat tenderizer nor a hammer seemed as exciting as before. I looked ...

4-Bit J-Input Logic Outline A Lovely Ice Cream Cake Happy Birthday to Me! Friday was filled with not only hard work but also a celebration. Right after the Science Center faculty lectures, my lab group surprised me with a chocolate-covered "Cookies and Cream" ice cream cake (and it was delicious) as well as lots of candy, limeade and a beautiful card. To say I was shocked would be an understatement. Now back to work! For the majority of the second week, I've been working on designing the 4x(4:1) multiplexer (mux) config and resolving issues in the switching between 16 channels by creating a 4-bit gray-code counter. On Friday, I was placing the last touches on the Logism simulation and checking if the output of the circuit matched that of the State Table, when Prof. Battat called me over. He showed me that he realized that we don't need a 4-Bit Gray Code Counter.... I had been working diligently for a whole week on a piece that we have ended up tossing aw...

4x(4:1) Mux Logic with Gray Code Breaking my blogging pattern, I'm writing about my work from today as I did quite a bit -- enough for one blog post. Following the last piece of writing, I corrected the logic table for the 4 x (4:1) to fit the specifications of our target multiplexer (mux)  LMH6574MA . However, after finishing it, I re-read Dr. Phillips's comments and noticed that, although the set-up diagram is great, it used binary code , meaning more than one input could change at a time and potentially generate a traffic jam with the break in signal patterns. Resultantly, we looked into utilizing gray code -- a digital code designed to allow only one bit (input) to change at a time -- to eliminate the possibility of multiple signal changes colliding into one another. 4x(4:1) Mux Logic with Binary Code Converting to gray code from binary wasn't too difficult and fortunately did not change most of my original design. I adapted the inputs to correlate with the gr...

electronics-tutorials.ws/combination/comb_2.html On to the second week of work! I believe I have finally started to cross the line from a state of first-time jitters to what I call the "honeymoon stage" -- when all seems hopefully bright and I am in love with my project -- or what others may call the "calm before the storm." Today, I began my work day very early to make-up for the time I lost yesterday, as I was well under the weather. I caught up on all the emails I missed from Prof. Battat and Dr. Phillips, making a list of to-do's before our telephone conference at 10 am. Whereas, in the last meeting, I leaned a bit backwards to make sure I understood the flow of the conversation, I came prepared to engage in this conversation and walk away from the table with a clearer vision of my mission. We discussed: the decision to daisy-chain (string together) four 4:1 multiplexers (mux) to generate what was equivalent to a 16:1, leading us to buy the evaluation ...

Since the last post, I have met with Prof. Battat several times to discuss current mini-goals and the overall framework for what we hope to be the end result. I have learned (most likely) over fifty different physics and electronics terms, read two papers on dark matter experimentation and lasted through a two-hour meeting between two very intelligent people on this particular project. I would call this a very successful first-week. For instance, yesterday, not only did I work more on the individual project and generate a Youtube playlist (below) of tutorials and lessons, I also gave a presentation on my progress through the week, had a group meeting to discuss the DRIFT experiment overall, and then jumped into a Python workshop. Today, I'll be busy again with an Alumnae lunch and a guest lecture in the afternoon on science education.  One day can pack in a whole lot.... On a similar note, two days ago, Prof. Battat and I met with Jim Phillips, who works at the Harva...

Yesterday, I started the morning off with the Science Center breakfast-orientation session, followed by safety training, and then sat down with Prof. Battat to discuss the progress of my project and the guidelines for future tasks, as well as general logistics. Simply put, I need to prepare to dive into a whale of a job. We discussed my findings for analog-to-digital data converters and how to refine my searches into the google spreadsheet (also placed on the  project site under the research tab ). Furthermore, we began discussing the overall end goal for the circuit, breaking the design down into three possibilities. Detector Vacuum System The Ideal Design The ideal design is to connect the signal wires (SW) from the detector to several high-ratio multiplexers (Mux), i.e. 16:1, and form a Mux chip. Then that chip will be connected to possibly an octal (8) ADC chip that allows each SW to be processed at 1 MHz or higher. Finally, the chip will release a low-voltage differe...