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Embedded Systems

The blog

The Final Stretch

T-minus 3 days till the final demo. Phillip and I have been making great progress! Fingers crossed we don't have to pull any all-nighters this week. Here are some updates:

Hardware:

We realized our old container can hold ~3.5 L of liquid. Phillip and I decided to change the dimensions of the box so it only holds ~2.5 L. The depth of the container went from ~6 cm. to ~4 cm. Since the columns of the new container are narrower, we were able to bring the error margin down from ~3.5 mL to ~2.1 mL. We spent a good amount of time in RPL a few days ago laser-cutting the parts for the new container. We were able to glue the front, bottom, and sides of the container together using a new type of acrylic cement that we bought at Everything Plastic. This cement is much thinner and stronger than the one we were previously using and can seep through cracks and corners. We wanted to use this acrylic cement first to glue pieces together and then reinforce the pieces with aquarium sealant, which is what Phillip did today with sealant we bought at Home Depot. We are currently waiting on aquarium sealant that our friend used last year for her project. The sealant should come tomorrow, so we can start reinforcing all the pieces soon! 

Note: We haven't glued the back or the top pieces of the container yet. We ran out of long-long male header pins in the lab so we had to order them last Friday. They should be coming in tomorrow, so once we get them, we will glue them onto the back piece and then glue the back piece onto the container. 

In addition to the new container, Phillip and I finished designing and laser-cutting the housing for the PCB, Arduino, and LCD. It looks so legit! We still have one more piece to glue to complete the housing, but we plan on doing that tomorrow while other pieces of the main container are drying.  

On another note, we decided to use the long female-to-male header pins that we will place between the conducting nodes on the container and the female header pins on the PCB. These pins will allow the PCB to easily fit onto the container and be easily removed, which is exactly what we want! 

Software:

Ladies and Gentlemen...the code works (we think)! We are able to output the current amount of liquid in the container, the urine output of the last hour, and the total amount of liquid outputted since the start of the hour. We weren't able to put a graph on the LCD because all the pins on the microcontroller with the Input Capture and Output Compare functionalities, used to detect button presses, are all being used (we would need the buttons to switch between displays of the LCD to show both the data and the graph). Phillip and I decided to just have the LCD screen display the information that Dr. Brooks said he would like to see (mentioned above). 

Circuitry:

Not much of an update here since the circuitry is basically done! Pactron, inc. set us three more copies of the PCB we have been using and testing for the past week. Since no changes have been made to the PCB, we have been using it as a measurement tool to determine the dimensions of the new container we are currently building.