Hand-washing logger with health worker category switches

In this, is the latest iteration of the hand-wash logging prototype, I have added four switches. As a registered nurse and ambulance officer I know from first-hand experience how we all hate filling in paperwork. This embedded logger records the date time and duration of a hand-wash event. Although it works very well, I realised I don’t know who is doing the hand-washing. To remedy this I have fitted four switches to the prototype. Each switch represents a category of health worker, namely: nurse, allied health, doctor and other. I will have a stick-on membrane matrix switch strip on the sink for the health worker to push before or during a hand-wash event.

A video of the upgraded logger can be found here: https://youtu.be/mCwyqt1lMmo

The picture below is a mock-up of a hand wash sink at our local hospital with the water proof membrane switch and piezo electric transducer in place.

The logger generates a .csv file that can be imported into Excel.

Hand washing event logger-working prototype

Hi, my hand washing event logger is now a working prototype. When I worked as a nurse in a medical unit a person was employed to stand and record hand washing events with a clip board. My device uses a piezo-electric transducer to provide ‘1s and 0s’ to an Arduino micro processor while water is flowing. The Arduino logs the date/time and duration of the hand wash event on an SD card.


The LCD shows the last hand wash logged time and duration. The picture below is a screen shot of the time, day, month and duration being logged on the SD card.


The aim of the project is to provide hand washing data collection using embedded technology. It doesn’t look very embedded at the moment! It is sitting on our kitchen bench logging sink events. Hopefully it will form the basis of a study in a hospital.


A hand-washing event logger

The most effective way of combating the spread of super bugs in our hospitals is simple low-tech hand washing. The aim of this project is to accurately log date/time and duration of each hand wash event at a sink. The logger has to be battery powered, unobtrusive and safe. I trialed Radio Frequency IDentification (RFID) with a wrist band on the clinician. The band triggered the logger but these devices have limited proximity.

I thought about a water sensor or an Infrared beam to trigger the logger but these devices produce a considerable lag-time. I am now trialing a piezo-electric transducer. The transducer produces a small current which can be filtered and amplified to trigger an Arduino micro controller. So far, I have solved the false-positive triggering and floating earth problems which produce erroneous readings. The proof of concept trial depicted in the following pictures is very encouraging.

The picture below shows the wave shaping prototype connected to the Arduino. The display shows no activity and a previous 8 second flow of water from the faucet.


The picture below shows filtered and shaped pulses coming from the transducer when the faucet is running.

Next I will add a real-time clock and SD card for logging purposes. The ultimate goal is WiFi linking to a central monitor. That shouldn’t be too hard!