PROJ01: SafeCup
Members: Douglas Pan, Kyle Trieu, Sia Chang, Stephanie Claudino Daffara, Yakira Mirabito
Designing for Emerging Technology, Fall 2019

Project Description
SafeCup is an interactive lid that keeps your drink safe while out. Spend less time worrying and more time enjoying yourself. The SafeCup experience starts when a bartender ID’s you, links your ID to the cup, and then pours you your favorite drink. Cheers! Next, lock your cup by the click of a button on the top of the lid. Wander away and upon returning, simply show your ID to your cup’s camera and it will unlock. If foul play by an unwarranted stranger occurs, LEDs with light up and flash, alerting those nearby. The idea was generated by a team of design students after observing the counter at the bar on a busy weekend night--folks often have to step away to use the restroom, chat with other friends or dance, leaving their drinks unattended.
Index
Project Description 1
Index 2
Observations 3
Design Process 4
Concept brainstorming (9/18) 4
Converging ideation and implementation (9/23) 5
System integration and refinement (9/25) 7
System integration 2 (9/27) 9
Future Iterations 10
Appendix: Instructable style process document step by step making of the work 11
Intro 11
Parts 11
Digital Files 11
Steps 11
Links 16
Observations
Location: Coin Op Arcade Bar
Duration: 2 hours
Stakeholders: Bartenders, customers, bar manager
Problem: Leaving drinks unattended. Heightened alert of watching your drink.
Notes:
- Some people seem to not care at all about their drink, some even lean against the bar backward, ignoring their drinks completely
- Some people held their drink the entire time, even while not drinking it
- Most women were facing their drink at all times
- A lot of the men would take their drinks to the gaming machines and rest it on the cup holder
- Someone gulped their drink in order to leave the bar area without worrying about their drink getting tampered with
- A couple put their drink on a table, and turned away from it, toward the pinball machine to play a game; Nothing happened to their drink, but many people walked past it
- Some people would buy drinks for a large group, and once the drinks were poured, they would abandon the drinks at the bar to gather their group and return to the drinks later
- Some groups took shots together, so there was little time of the drink sitting at the bar with liquid in it still
- I asked one lady who left her drink at a table: “Aren't you worried someone might do something with your drink?” She replied “Oh my god, you are right,” and immediately went to grab it. The guy with her said “Why don’t you just leave it in the cup holders instead?” She replied, “They are too deep and the cup is too small.”
Key insights:
- Sometimes people drink their drink quickly just so they don’t have to be alert.
- Sometimes people even chug their drink before going to the bathroom.
- Most people ask a trusted friend to watch their drink, but sometimes they're also distracted.
- Many people carry their drink wherever they go walk around, but it becomes harder to do so when they want to play arcade games.
- People watching their own drinks in low-light environments can be challenging.
Design Process
Concept brainstorming (9/18)
During class, we discussed the basic requirements for the project and generated two concepts as shown in Fig. 1. The cup idea was generated based on observations a few days prior. However, the interactive tip jar served as a design alternative that also focused on the bar counter but could extend beyond a bar setting.
1) a cup for while out at a bar
2) interactive tip jar

Fig. 1: Two concepts generated in-class brainstorm
Converging ideation and implementation (9/23)
This work session served as a key decision-making point. The concept surrounding keeping your drink safe was deemed more impactful and thus as a team, we headed in that direction. We sought advice from the professors regarding utilizing a cup or storage device that bars would install. Upon deliberation, we ultimately ended up with the decision of an interactive lid.
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As a team we hashed out the overall features of the lid that we would like to incorporate, then assigned specific components each person owned.

Fig. 2: Whiteboard space for questions and division of labor

Fig. 3: (Left to right) LEDs on lid, locking mechanism, and external housing
External lid design - Yakira
- Used Fusion 360 to model lid
- Careful measurements were taken from the cup
- Printed lid iterations on Ultimakers in Jacobs/CITRIS Invention Lab
- Iteration one - ended up being a bit too bulky with 5 mm + of unnecessary thickness
- Iteration two - thinned down walls; optimized shape to minimize support material during print
- Jacobs printers were backed up for days - Addressed by using Invention Lab equipment; In the process learned about Moffitt 3D printers

Fig. 4: Image of the final external lid in Fusion
LED light system - Kyle
- Soldered power, ground, and digital communication wires to Neopixel strip
- Used thinnest wires available in Invention Lab: 24 AWG
- Any size wire would do; we weren’t going to hit the maximum current rating
- Thinner wires lent themselves better to the design, to minimize volume occupied and to reduce the appearance of wires
- Solder joints & wires were susceptible to breaking due to how much wires were bending during transportation and while assembling the design
- Hot glued solder joints to ensure that wires remained connected
Open & close mechanism - Sia
- Rotating sector-shaped cover: open and close the drinking hole
- The material we decided on is acrylic to reduce friction and create a smoother rotation, which also matches the overall transparent lid design style
- Thickness: ⅛ inch
ID reader and Raspberry Pi integration - Stephanie and Doug
- The Raspberry Pi camera is a fixed focus camera. For things that are to be read/detected a short distance away, the camera should be adjusted so the focal plane is closer. If the focal plane is far, the image will be blurry and it becomes difficult for Google Cloud Vision to detect faces in an image.

Fig. 5: Stranger peeking into the cup with an “angry” face which prompts the cup to blink red.
- Making the Raspberry Pi portable was surprisingly easy. Connecting a cell phone power pack to the Pi and Crickit Hat allowed us to become untethered from the wall. The device seemed to have several hours of operation before the battery drained.
- The use of facial data or even driver’s license information was controversial. Since the device relied on cloud computation, face and ID data were constantly sent from the device to Google’s Cloud API whose policy over data ownership and storage were unclear. Therefore, some team members did not want to test the device with their face or ID card. When designing future devices that can perceive, how do we address those data privacy concerns? And how do we prove that a user’s data is private? Can we do so without providing access to the source code?
- During the time between work sessions, we made major revisions on the perception aspect of the project after discovering two issues. First, Google Cloud Vision service detects faces but does not recognize them (it cannot distinguish between specific faces). Second, the service requires the faces to be oriented in an upright position before it can detect them.
- Since a person could look at the lid from multiple directions, it was important for us to detect faces in an image regardless of orientation. If we couldn’t even detect faces, how would we recognize them? We tried rotating captured images and sending each one to Google Cloud for analysis. It took too long to send multiple images and receive multiple responses. The lid seemed frozen and unresponsive. Therefore, we abandoned the idea of facial recognition and looked to decoding a license number instead.
System integration and refinement (9/25)
Integrating each individual component revealed new challenges. First, the servo motor was free-standing, which meant it was tricky to secure the lid. This was addressed by modifying the inner lid to hold the servo in place. This component was 3d printed rather than laser cut (as in the previous edition). The servo could be attached securely as shown in Fig. 6, and allows for proper travel of the lock. Note the tab that rotates was laser cut with clear acrylic.
Despite this new challenge, the functional prototype worked. For the next iteration, we needed to simplify the design, remove bulky features and approach it with a more aesthetic eye.

Fig. 6. Updated open-close mechanism
System integration 2 (9/27)
During this work session, we tested all the improved parts and integrated all the subcomponents as shown in Fig. 7. The parts seamlessly fit together as shown in Fig. 8. One should note while this edition housed many of the electronics inside, future iterations would include more compact electronics that could fit right on the lid.

Fig. 7: Second iteration of the open/close mechanism

Fig. 8: Cup with all interactive components
Future Iterations
The current iteration of SafeCup focuses on the basic functions of ID recognition, locking, unlocking and visual notification to the bartender. This set of features is designed to improve the experience for the person at the bar.
Barring concerns about personal and data privacy, we see the SafeCup improving in several ways to increase adoption by businesses.
Improvements
- Software features
- Patron and drink analytics. The SafeCup could provide bar owners data about age/gender/race along that is tied to drink selection/frequency. This would make it easier to quantify decisions around drink promotions, menu size, seasonal trends in order to maximize profits.
- Bar liability. In many states, bars are responsible for serving a drunk person who then causes an accident. However, training and enforcement of this is not uniform across all bars, or even amongst bartenders. The SafeCup could reduce the risk that a bar takes in serving customers by automatically cutting off a patron once some set limit is reached.
- Hardware features
- Easy to clean. In order for a business to adopt the SafeCup, its life cost (acquisition + maintenance) must be low. The next iteration of the SafeCup would look at mean time-to-failure, and ease of cleaning the lids. While the SafeCup creates a safer drinking environment, it would be disgusting to be handed a dirty SafeCup. The SafeCup lid must be as easy to clean and handle as the bar’s glassware.
- Different form factors. We would also look at different form factors in order to maximize use. Bars stock a variety of glassware for different drinks. The SafeCup must be versatile so that it can be used with the most common types of glassware.
Appendix: Instructable style process document step by step making of the work
Intro
This document covers step by step assembly and function of the SafeCup
Parts
1 Raspberry Pi
1 Crickit Hat for Raspberry Pi
1 NeoPixel LED strip (10 LEDs)
1 Raspberry Pi Cameras V1
1 Pushbutton
1 External Lid (3D printed)
1 Upper Lid (3D printed)
1 Closure Tab (Laser Cut)
1 MG966R Servo
4 10-24 3/4IN Socket Cap Screw
Digital Files
Code:
https://github.com/dougspan-bear/det_proj1
Lid:
https://drive.google.com/open?id=1YHDGWgtN9ePmSt40dpp32WZkdOspK62h
Acrylic Piece: https://drive.google.com/file/d/1WJwXXR3w0iyCuj3JonIUH6RoPlBjg5Ty/view?usp=sharing
Steps
- 3D print/laser cut parts
- Print external lid

Fig. A1: Model of external lid in Cura
- Print center of the lid

Fig. A2: Model of inner lid in Cura
- Laser cut closure tab component

Fig. A3: Clear closure tab (already adhered to inner lid component)
- Assemble the upper lid
- Attach camera to middle lid component

Fig. A4: Camera inserted to inner lid component
- Attach lid closure tab to servo

Fig. A5: Closure lid attached to servo and servo attached to inner lid
- Secure servo to holder in middle lid component
- Note: Secured using 4x 10-24 3/4IN screws
- Assemble the external lid
- Add LED around external lid

Fig. A6: LEDs adhered to external lid design
- Add pushbutton on handle of cup

Fig. A7: Lock button adhered to external lid design
- Assemble the external lid and upper lid
- Attach middle lid to external lid

Fig. A8: Inner and external lid components integrated
- Assemble the Raspberry Pi + Crickit Hat
- Wire up Raspberry Pi and Crickit Hat

Fig. A9: Raspberry Pi and Crickit Hat
- Attach portable power source
- Put all subassemblies together

Fig. A10: Electronic components (excluding servo motor)

Fig. A11: Finished design (all electronic components housed inside)
- Update the software on the Raspberry PI

Fig. A12. Cup flashing green lights indicating either that it has registered a new ID or that it has identified a correct ID
Links