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TPA81 Devantech 8 Pixel Thermal Array Sensor

Vendor's Description: 

The TPA81 sensor is a thermopile array detecting infra-red in the 2um-22um range. This is the wavelength of radiant heat. The Pyro-electric sensors that are used commonly in burglar alarms and to switch on outside lights, detect infra-red in the same waveband. These Pyro-electric sensors can only detect a change in heat levels though - hence they are movement detectors. Although useful in robotics, their applications are limited as they are unable to detect and measure the temperature of a static heat source. Another type of sensor is the thermopile array. These are used in non-contact infra-red thermometers. They have a very wide detection angle or field of view (FOV) of around 100° and need either shrouding or a lens or commonly both to get a more useful FOV of around 12°. Some have a built in lens. More recently sensors with an array of thermopiles, built in electronics and a silicon lens have become available. This is the type used in the TPA81.

It has a array of eight thermopiles arranged in a row. The TPA81 can measure the temperature of 8 adjacent points simultaneously. The TPA81 can also control a servo motor to pan the module and build up a thermal image.

Here's a link for full technical specs.

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Hi there

          Im currently doin my school project which uses the TPA81 sensor.. My project is about Heat Seeking Fan where the sensor detects human body temperature who is feeling hot ,the fan will slow down and pays more attention to the user. Once he cools down n back to the normal temperature (35.7 degree Celsius) , the fan will rotate as per normal...

I am using a Mini Atom Carrier Board(Bot Board 2) and a TPA 81 Thermal Sensor together. I have already connected the sensor to the board and i was wondering if you would be able to help me with PBasic codes. I kind of need to set one of the I/O to connect to an electronic relay and to activate it.

How very thoughtful of you. That is something nice and useful. Im also doing a human temperature thing for my project, but with different intentions ;-)

I have seen this unit mentioned many times now... We NEED someone to buy one and show it working already!


Your wish is my command :)


Cow, it looks like your bully-bot is tracking you with this sensor? Is that right? I thought this sensor just worked like a glorified PIR ...

Yeah, the sensor provides the temperature in degrees C of eight 'pixels' spaced horizontally, plus the ambient temperature. I wrote the code to use that information to track a warm human body, which for now I'm defining as "something that is at least 29 C, and that is also at least 3 deg C above the ambient room temperature." So if the room gets too warm, then it can't reliably isolate humans from the background noise, so I coded it to 'fail safe' rather than have it shooting at every slightly warmer spot in the room :)


Hi, what is the distance range of the detector?

Can it be used outside for up to say 30 meters or more?



What is the difference between this and a PIR? I am not sure they actually focus on the same wavelenghts...