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Wireless Bubble Sensor

TE Connectivity’s AD-101 Bubble Detector is an ultrasonic-based sensor that detects presence (or lack of presence) of liquid in tubing passing through the sensor.

TE Connectivity’s AS-101 air bubble detector. (Image source: TE Connectivity)

The sensor is easy to use and has just four leads: 1 – GND, 2 – Output, 3 – Self Test, 4 - Power. The sensor output is 3.3 V TTL (low when liquid present, high when bubble present).

Project Background

The AD-101 is primarily intended for medical applications, but I wanted to come up with a practical project to demonstrate ease of use. Water level detectors are simple instruments that have been around for thousands of years and I thought it would make a great project to highlight the AD-101 sensor’s features and provide a remote visual LED level indicator. A low-cost water level detector was modified to add a length of tubing to pass through the sensor. The sensor changes state when water is present and triggers the remote level indicator.

Wireless hardware was developed for the project to monitor the AD-101 output and trigger a remote LED indicator. The wireless hardware consists of a pair of Digi International XB3-24Z8US-J modules mounted on Grove sensor boards inside of waterproof Bud Industries PN-1323-CMB enclosures. Micropython scripts running on the XB3 modules perform the functions of setting up the wireless link, monitoring the sensor and triggering the remote LED. Complete project details are documented in the eeWiki article Wireless Water Level using the AD-101 Bubble Detector and XBee3.

About this author

Image of Scott Raeker

Scott Raeker, Technical Marketing Manager at Digi-Key Electronics, has been with the company since 2006. He has over 35 years of experience in the electronics industry and holds an Electrical Engineering degree from the University of Minnesota. In his spare time, Scott enjoys the outdoors of Northwest Minnesota and working on his turn-of-the-century farmhouse.

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