Design Review 4: April 26th
Agenda:
- Attendance
- Meeting Leader: Richard McManus
- Minutes: Mike Slusarczyk
- Review System Requirements
- Complete System Demonstration
- Board talk and explanation
- Code discussion walk through
- Make a cup of coffee!
- Try different mugs and different size brews
- Questions for Schafer
- Do you want to see another demo with our revised boards?
- Will it negatively impact us if we use the existing boards in our final project?
Subsystem Requirements
Subsystem 1: Cup Sensing
The cup sensing subsystem is required to 1) determine when a cup has been placed under the nozzle and 2) measure the height of the cup. The system is required to accommodate cylindrical cups at least as large as 8 inches in height and 4 inches in diameter. The system must also accommodate cups of various colors and textures including translucent cups. The subsystem should also be robust against external factors such as ambient light and sound. This system must not present safety hazards to the user including but not limited to the possibility of laser exposure. The sensing system must also be automatic and require no prior knowledge of the cup. Additionally, the system should provide the user with immediate feedback regarding the detection of a cup and its corresponding height. This data must also be provided as inputs to the main board to control the brewing of coffee.
Subsystem 2: Mainboard
This subsystem consists of a custom circuit focused on control and connectivity. At the heart of the board will sit our main processor. First and foremost, this board must allow us to brew a hot cup of coffee using the existing Keurig hardware. Regarding processing, the board is responsible for all of the I/O of the coffee. That is, the mainboard will take in data from the sensors and the touchscreen. The processor is required to interpret this data (i.e. cup height, user preferences, amount of coffee poured) and then use this data to control the output devices in this system. Those devices may include an external PSU, water pump, heating unit, temp sensors, indicator lights, and speaker. For the coffee machine to work, the board must be able to process the inputs and control the outputs in real-time; meaning, this machine relies on being able to quickly sense how filled the cup is and control the pouring of coffee instantly.
Subsystem 3: Coffee Pour Tracking
The coffee pour tracking subsystem must periodically measure the height of the liquid inside the cup; relatively frequent measurement is necessary to prevent overflow. This measurement system must accommodate distances between one and eight inches. The system must also be capable of measuring distances to both solids (the bottom of the cup) and liquids and must accommodate a variety of colors and transparencies. The tracking subsystem should be unimpeded by the stream of coffee being poured or the inherent steam produced from brewing hot drinks. The subsystem should also be robust against external factors such as ambient light and sound.
Subsystem 4: User Interaction
Brewing must not begin in the absence of a cup as determined by the cup sensing subsystem. Physically, a button will be implemented to initiate brewing. The system should provide visual feedback to the user on the brewing and pouring status (i.e. cup filled percentage) and alert the user when the water tank requires refilling. In addition, the whole system must mesh relatively seamlessly with the body of a single use coffee maker, maintaining the aesthetics of the original. It must also not incur a substantial additional cost compared to the cost of single use coffee makers themselves