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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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I bought mine from robotshop.us -- I found it for $99, but it seems to have gone up to $110 now. I'll post some thoughts and Arduino code once I've had a little more time to play with it.


What is the difference between this and a PIR? I am not sure they actually focus on the same wavelenghts...
The difference between this and a PIR is that this thing will give you 8 actual readings while a PIR only gives one signal when a change occurs. Hook this baby up to a servo that move left to right in, lets say, 8 steps: you get an 8x8 thermal picture.

aww! just found out that PIRs are actually the pyroelectric sensors you were talking about, now i get the difference :)

I would really love to have one of those, maybe i'll pick one when i'll have some more money 

by the way...here it costs much less http://www.hvwtech.com/products_view.asp?ProductID=947 

What! $63? That's gotta be wrong. Of course, they're out of stock... I'll keep an eye on that page :)


unfortunatly this one has been "temporarilly sold out" for a while....  :( 

I'm starting to wonder if they get em and sell em out that quick...

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 :)