Is the Bathroom Free? Find Out with Occup-Pi!

Need to find out if the bathroom is free or not, without negotiating a flight of stairs, or meandering along the corridor? It seems the answer to your inconvenience has been found, courtesy of’s Brian W Wolter.

Following an office downsize, Brian and his colleagues found that they had fewer restrooms. The answer was to create a system that alerted when the toilet was free, and for this, Wolter chose a Raspberry Pi.

As explained in this Noteworthy entry, Wolter and his coworkers “figured that if we could find a way to better coordinate bathroom access and advertise availability we could avoid spikes in usage that make annoying lines. We needed a sensor that could determine and broadcast the bathroom’s availability.”

Eschewing motion sensors and facial recognition, the Occu-Pi utilises the bathroom lock, much like an airplane toilet. Once the toilet door is closed and locked from the inside, the Occu-Pi sends an alert to colleagues via Slack.

Costing around $75, this build features a Raspberry Pi 3, power adaptor, GPIO breakout board (such as the Pibrella), magnetic switch, barrel bolt lock, and a small cylindrical magnet. You’ll also need to make arrangements to mount the Raspberry Pi close to the barrel bolt.

Once closed, the magnet mounted on the barrel bolt triggers the magnetic switch; this is connected to the Pi’s GPIO, which triggers the controller software (written in Go, and available from GitHub). When the door is opened or locked, a message is sent via a remote service (for example, AWS Lambda) where a function is triggered.

With some calibration, the Occu-Pi should offer an accurate representation of the bathroom’s occupied status. Alerts might be sent via email, perhaps SMS, perhaps alongside a visible LED alert. There might even be a spare LCD monitor that could be co-opted to display the bathroom status. Or, like Wolter and his team, you might employ your online chat/collaboration tool, such as Slack, or some other network-based alert system.

Whatever the output, just ensure that everyone is happy with the outcome; toilet time can be very personal...

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