Elijah Knupp’s status report for April 6th

This week’s accomplishments

• Attended mandatory labs
  • Demonstrated my portion of the project to Prof. Fedder and the TAs, received positive feedback
• Added a manual taring feature the user can trigger at any time to zero the scale
• Completed the Arduino’s script for the temperature probe, scale, heater, and PID loop
  • sends serial data from the temperature probe and scale
  • sends a confirmation signal back to the rpi that the change it requested from the PID loop was implemented
  • receives serial input
    • user can send a signal to manually tare the scale
    • receives signals from the rpi-implemented PID loop and turns the water heater on and off wrt to the signal’s value
• Began testing the PID loop to control the heating element
  • Very close to being fully implemented
    • currently, the loop overshoots the target temperature by around 2-3 degrees Fahrenheit

Next weeks plan

• Implement the pump into the project.
  • will need to ensure the pump’s flow rate are accurate per the user’s request
    • see testing plan below
• Finish testing and verifying the PID loop for the heating element
  • see testing plan below
• begin fabricating all of the different components on to the 3-D printer’s frame
  • will need to 3-D print a mount for the water pump. Will be placed on the very top of the frame.

Status Report: On schedule

 

Verification and Validation

• Verification:
  • Heating element: As per the design project report, we aim to deliver water within +-5 degrees Fahrenheit of what the user specifies. Mentioned above, we are currently overshooting the temperature by only a couple of degrees. However, this may be necessary due to thermal loss whilst the water travels through the lines, as this temperature reading was taken inside the water heater.
    • TEST
      • Need to test the FULL range of temperatures the user can request (from around 180 – 212 degrees Fahrenheit)
        • Every 4 degrees (180, 184, … 212), will ensure that the temperature of the water hits the coffee grounds at +-5 degrees from the users request (although we will shoot for +-3 degrees)
  • Scale
    • Testing will be simple. The user will be using the integrated scale to check the amount of coffee grounds they have placed into the filter
      • TEST
        • Need to test the full range of weights of coffee grounds the user may use (around 10 – 40 grams of coffee grounds)
          • Every 5 grams, use a known weight to ensure the weight readings are accurate
• Validation
  • The water system needs to be safe and intuitive for the user. Whilst the software side is being handled by Rio, I will need to make sure that user can easily and SAFELY handle the water system. I will need to ensure that there are no exposed wires or electronics that could be exposed and damaged if some water is spilled around our machine.
    • As of now, the user will need to unscrew the cap of the water heater (which is a converted electric kettle), which will have the temperature probe and tubing attached to this.
      • TEST:
        • I will ask several individuals to screw and unscrew the lid to ensure ease of use and durability of system.
    • Cable management is a major component of this as well. I will need to make sure that no wires could jar loose or come exposed.