Piezo MEMS based ultrasonic sensors look to break into new applications

1 min read

Looking to take advantage of a move to smaller sensors in a range of consumer electronics products, Chirp Microsystems has launched two ultrasonic time of flight sensors. Called the CH-101 and 201, the parts are said to be the smallest and lowest power devices of their kind currently available.

Dave Horsley, chief technology officer, said: “We’re aiming these parts at consumer electronics applications, such as drones, as well as apps where ultrasonic sensors are already used. But there’s a range of other devices where current technology is too large to be applied.”

Horsley believes the way in which we interact with ‘things’ is changing. “The Wii brought in motion control, while the iPhone introduced touch technology. Now, things like Amazon Echo are bringing voice control. We think natural motion detection will be the next revolution and believe that ultrasonic sensing could have the same kind of impact as earlier technologies.”

The CH-101 and CH-201 measure range by emitting an ultrasonic ‘chirp’, then listening for echoes returning from objects in the sensor’s field-of-view. The CH-101 has a detection range from 1cm to 1m, with sub mm accuracy, while the CH-201 can detect objects within the range from 20cm to 5m, again with mm accuracy. Sub mm accuracy, said Horsley, is being demanded by applications such as virtual reality.

“Current ultrasonic sensors are too big for consumer products,” Horsley contended. “Our parts have the same functionality and people are surprised they can do the same things with a transducer that’s 1000 times smaller.”

Manufactured using a piezoelectric MEMS technology, the sensor measures 1 x 1mm and is packaged with an asic into a chip measuring 3.5 x 3.5mm. Both parts run from a 1.8V supply and have an I2C interface. Total current consumption is 8µA when taking 1sample/s, but Horsley said the parts draw less than 0.5mW at 100sample/s.

“There’s a lot of things you can do with ultrasonic sensors,” Horsley concluded, “and you will see them going into a lot of products. A decade ago, you wouldn’t have thought of having gyroscopes in watches, but there will be products launched in 2018 featuring these parts.”