Project Portfolio

Dan Maynes Aminzade


Actuated Workbench
Audience Interaction
You're in Control
Edible User Interfaces


Carnegie Mellon


Disney Imagineering


Unsafe Search
Music Visualization
Taboo Database


Pepsi Database
Love Calculator


RCA Lyra
Stone Cold


SURG Proposals
Female Pop Singers
Satan Baby
Wesley Willis

You're In Control

You're In Control short paper, presented at CHI 2003 in Fort Lauderdale, Florida.

You're In Control video (4.8 MB).

The You’re In Control system uses computation to enhance the act of urination. Sensors in the back of a urinal detect the position of impact of a stream of urine, enabling the user to play interactive games on a screen mounted above the urinal.

A user interacts with the
You're In Control system.

While urination fulfills a basic bodily function, it is also an activity rich with social significance. Along with the refreshing release it provides, the act of micturition satisfies a primal urge to mark our territory. For women who visit the bathroom in groups and chat in neighboring stalls, urination can be a bonding ritual. For men who write their names in the snow, extinguish cigarettes, or congregate around lampposts to urinate, urination can be a test of skill and a way of asserting their masculinity.

The You’re In Control project is an effort to enhance the act of urination using computational technology. We believe that adding interactivity to urination has valuable applications to recreation, sanitation, and education.

We mounted a urinal to a freestanding sheetrock partition, and affixed a flat-panel LCD screen to a frame above the urinal. Since the flush-valve was not functional, we routed sensor wires from the urinal basin through the chrome-plated plumbing fixtures to the circuit board and computer behind the wall.

In order to allow both men and women to participate in the demonstration, we created a customized game controller, consisting of a nylon belt, a formed acrylic pelvic plate, water bottles, tubing, and a flexible garden hose nozzle. The controller is worn around the waist and the bottles are gripped and squeezed to pressurize a stream of water.

Custom input controller
consisting of rubber
nozzle with attached
water reservoirs.

We built the You’re In Control system with a grid of piezoelectric ceramic buzzers mounted to a flexible Mylar membrane. Foam tape mechanically isolates areas of the Mylar from one another, and local sensors measure deformations of the membrane in response to a liquid stream. When the sensor array was mounted to the compound curved surface of the urinal, the membrane had uneven tension over its surface. This resulted in slightly uneven sensor outputs because tighter areas deformed less in response to the water stream. We addressed this inconsistency by custom-tuning the amplifying circuits to deliver uniform signals to the microcontroller.

The two-stage signal processing circuit uses an amplifier with a gain ranging from 10-100 and an envelope follower to curb the signal attenuation. A 16F877 PIC microcontroller receives the signals as digital inputs. The impact of a stream of liquid creates a signal that breaks the 2.5-Volt threshold necessary to send the microcontroller’s digital inputs high. We chose to use digital inputs because they can be read more rapidly, and we found that the resolution provided by the digital inputs was sufficient for designing a compelling interactive activity.

Screen shot from our interactive game.

We programmed a custom interactive game in C++ on the Windows 2000 operating system. Our software reads the state of the sensor array from the microcontroller over a serial data link at a rate of 100 samples per second. The game we chose was a variant of Whack-A-Mole, a classic carnival game. Users aim at a series of jumping hamsters, with input position on the urinal corresponding to target position on the screen above. A successful hit turns a hamster yellow, makes it scream and spin out of control, and rewards the player with ten points. The parabolic trajectories of the hamsters conceal the grid-like arrangement of sensors, resulting in a fluid transition between input and output.

We believe that the You’re In Control system offers many advantages over traditional bathroom fixtures:

Improved sanitation. Since our system motivates users to aim properly, it reduces splashing and spillage.

Hydration. By making urination more fun, the You’re In Control system encourages proper hydration, and could result in increased beverage sales at restaurants and sporting events.

Potty training. You’re In Control could also be used to teach children proper bathroom behavior at an early age.

Entertainment. While urinating outdoors is playful for many people, bathroom sanitation requires a serious focus and conformity. You're In Control encourages cleanliness while reintroducing play to the act of micturition.