Pesky Products' PAF9701C1 Breakout Is a Cheap, Energy-Efficient Introduction to Thermal Imaging

This open-hardware breakout is a great way to break in to low-resolution yet high-accuracy thermal sensing for imaging, motion, and more.

Gareth Halfacree
a month agoSensors

Maker Kris Winer's Pesky Products has launched a low-cost thermal sensor breakout board, based on PixArt Imaging's PAF9701C1 low-power IR sensor array — and offering an 8x8 measurement matrix with ±1 degree accuracy.

"I love sensors (who doesn't?), especially imaging sensors," Winer explains of his inspiration for the project. "These are not traditional imaging cameras, and each offers a new way to map events in 2D either via range (distance), optical flow (velocity) or temperature. These sensors are easy to use with simple serial (I2C or SPI) peripherals, don't require a lot of GPIOs to make work, and are compatible with ultra-low power applications."

The breakout, which comes with Arduino sketches to get the user started, is designed to communicate via I2C and offer live readouts of an 8x8 thermal sensor matrix — data that can be color-coded and displayed as a live thermal camera readout on a simple display.

"The sensor has an interrupt pin that can be configured for data ready or over-/under-temperature threshold (either absolute or differential) alerts," Winer adds. "Furthermore, each pixel that exceeds the threshold limit can easily be identified. This makes it straightforward to track motion in the temperature field for directional transit monitoring, estimating people count in a room, or simple object detection."

The sensor itself is designed to draw as little power as possible: In a sample sketch designed to showcase its power-saving capabilities, the sensor starts off drawing 2mA then drops to a 20-second alert period at 310µA — then to a 120-second alert period drawing just 52µA.

"The power usage drops by factors of ~6-7 at each stage and the latency increases by about the same amount," Winer writes of the power-saving mode. "This provides a way for the user to manage power usage that is very convenient and effective, and offers enough flexibility that the power usage and latency can be tailored to the specific application without elaborate host programming."

The breakout board is available to buy on the Pesky Products Tindie store now at $49.95, while the board design files have been published on OSH Park. The sample Arduino sketches, meanwhile, are available on GitHub under the permissive MIT license.

Gareth Halfacree
Freelance journalist, technical author, hacker, tinkerer, erstwhile sysadmin. For hire: freelance@halfacree.co.uk.
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