SipSafe: Smart Drink Protection

"Drink covers protect your drink. SipSafe protects you."

Inspiration

The statistics are alarming. According to RAINN, 1 in 5 women in college experiences sexual assault, and approximately 11% of women and 3% of men report being sexually assaulted while incapacitated since entering college. Around 65% of 18-24 year-olds report they or someone they know has had a drink spiked.

Products like the NightCap scrunchie have emerged as a response to this worrisome trend, fabric covers that stretch over drinks to prevent pills and powders from being dropped in. They work as an excellent deterrent to stop spiked drinks, but they have a glaring weakness.

"Can't someone just remove the NightCap drink cover?"

According to the manufactures themselves: "NightCap is NOT an excuse to leave your drink unattended."

We asked a different question: What if the cover could tell you when it's been tampered with?

What It Does

SipSafe is a smart drink cover that alerts you the moment someone touches it. Using capacitive touch sensing technology embedded in the fabric, SipSafe detects human contact and instantly:

Sounds an audible alarm via piezo buzzer Sends a push notification to your and added friends phones Logs the incident in the iOS app

The system can be armed and disarmed via the app allowing for users to go about their night unimpeded by bulky locking systems

How We Built It

Hardware

ESP32 microcontroller with built-in Bluetooth Low Energy (BLE)
Capacitive touch sensing using the ESP32's native touch pins—no special conductive materials needed, just aluminum foil connected to GPIO 4
Piezo buzzer for audible alerts with distinct sound patterns:

Software

iOS app in Swift featuring:
- BLE device scanning and pairing
- Real-time status monitoring
- Push notifications for alerts

The Detection Method

We explored several sensing approaches before landing on capacitive touch:

Method	Problem
Magnetic reed switch	Requires attachment to cup
Photoresistor	False triggers from club lighting
Stretch sensors	Can be defeated by careful removal
Conductive elastic	Hard to source at a hackathon

Capacitive touch was the winner because:

Only human skin triggers it (not glass, ceramic, or plastic)
Single wire to aluminum foil
ESP32 has built-in support, no extra components needed
Foil can be hidden on the underside of the cover

Challenges We Faced

False trigger prevention: Early prototypes triggered from the cup rim contact. Testing revealed that glass/ceramic/plastic don't affect capacitance readings—only human touch does.
Mechanical detection limitations: We initially tried button-based detection but couldn't get enough tension from the elastic band to reliably depress buttons.

What's Next

Miniaturization: Smaller ESP32 boards (like ESP32-C3) and LiPo batteries for a more discreet form factor
Android app: Expand beyond iOS
Multiple touch zones: Detect where the cover was touched
Integration with venues: Alert bar staff when tampering is detected
Manufacturing partnership: Work with existing drink cover brands to integrate our technology