Gene Lu's Portfolio

Hand Wash Tracker

Due to the recent Swine Flu outbreak, our team created a handwash tracker that keeps track of the handwashing habit of the interaction design department.

Team Members
Colleen Miller, Eric St. Onge, Michael Katayama, and Gene Lu

Men's restroom handwashing observations

Men's restroom handwashing observations

The Problem
According to the American Society of Microbiology, studies show that 97% of females and 92% of males say they wash their hands, but in actuality, only 75% of females and 58% of males actually did wash. In middle and high schools, 50% of the students say they wash, but only 33% of females and only 8% of males used soap while washing hands.

To check whether these statistics were credible, we did some informal observations in the men’s bathroom at both the Port Authority and Penn station (yeah, it was as bad as it sounds). The results are shown in the pie chart to the right. Just imagine everything these people come in contact with once they leave the bathroom. Doesn’t it make you just want to run out and buy some antibacterial soap?!

The Solution
The handwash tracker is a system that informs people outside of the bathroom whether or not the current bathroom user has washed their hands. It also keeps track of the level of cleanliness of that bathroom, which is based on the average number of users that have washed their hands.

Prototype 1
The first prototype consisted of an arduino board that was programmed to detect the following inputs: 1) door lock, which engaged the system whenever the door was locked, and 2) soap dispenser, which determined whether or not the bathroom patron washed their hands. The outputs were as follows: 1) meter display showing the level of cleanliness of the bathroom, and 2) an LED that lights up whenever a user washes their hands.

1st prototype with Arduino and a open switch circuit rigged throughout the bathroom

1st prototype with Arduino and a open switch circuit rigged throughout the bathroom

Observations with Prototype 1
As with all prototypes, especially initial ones, we had a couple of hiccups come up:

  • 9V battery died quickly
  • In addition to being alerted when the last patron washed, it would also be helpful to know if they didn’t
  • After many uses of the restroom, the output ratio of clean vs. dirty did not move the meter significantly
  • The force sensor in the soap dispenser was being crushed

Prototype 2
In this second prototype, we increased the life span of the battery by sleeping the servo motor (the pointer on the meter) when the system was not in use. We also added additional outputs for non-washers along with a surprisingly effective “occupied” light. In regards to the output ratio of clean vs. dirty, we edited the percentage to be based on a moving average. As for the force sensor, we hacked the soap dispenser with a wire connected to the metal soap box and another wire connected to a sheet of foil behind the dispenser button making this a large version of a momentary switch.

Observations with Prototype 2
After making our changes, we found that the second prototype was much more effective with its additional outputs.

2nd prototype

2nd prototype

Rewiring the Handwashing Tracker with additional outputs

Rewiring the Handwashing Tracker with additional outputs

Hacked Soap Dispenser

Hacked Soap Dispenser

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  • 09 Dec 2009

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