Inside a wearable ozone meter with alarm.

This fairly expensive unit is designed to monitor ambient ozone levels and sound an alarm and vibrate if they exceed a preset threshold. I'd guess it is intended for factories where ozone is used in processing.

Inside is a fairly standard sensor, possibly based on tin oxide technology, that changes resistance according to ozone level. The case has clearly been repurposed from one designed for up to four separate round sensors. That means the sensor is mounted well inside which slows down the units response significantly unless a flow of air is directed at it.

This unit came from eBay. I was hoping it would have greater sensitivity and resolution at the lower levels for ambient testing, but it seems more suited to detecting higher levels.

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