Building a thermal imaging sensor from scratch

[Rob] lives in a 100-year-old house, and with these antique lath and plaster walls and old window frames comes a terrible amount of drafts. The usual way to combat this energy inefficiency is with a thermal imaging camera, a device that overlays the temperature of an object with a video image. These cameras are hideously expensive so [Rob] did what any of us would do and built his own.

The build centers around a Melexis MLX90620 far infrared thermopile that can be had for about $80. Basically, this sensor is a very, very low resolution camera (16×4 pixels) that senses heat instead of light. By sticking this sensor on a breadboard with an Arduino Mini and WiFly network adapter, [Rob] is able to pull the data down from the IR sensor to his iPhone and overlay it on the feed from the camera.

The result, as seen in the video above, is a low-resolution but still very useful thermal imaging camera, perfect for looking for cold drafts in an old house or tracking down [Arnie] just like a Predator.

Tip ‘o the hat to [Ronald] for sending this one in.


  1. Kaj says:

    Open source, tidy, well executed, and practical. Sweeeet.

  2. bunedoggle says:

    That’s a whole bag of win right there! Nicely.

  3. Phil F says:

    Nice, but for drafts I usually just use Tea Candles. I can imagine this would help locate damp spots though.

  4. SOI Sentinel says:

    Nice! I didn’t know they had an array like that. I’ve been looking at 8×8 and 32×32 arrays, but they’re pricey (qty 100, approx $100 and $400 respectively).

    For the curious, that was a year and a half ago:

    This one, though, is all digital, not a clocked analog signal like those Heimann sensors I had found. the achieveable framerate is very impressive, too (at a loss of accuracy of course).

    Very nice, though. thermal cameras can be a pain to use because you can lose your frame of reference to find a thermal point. Now, you may not get all the thermal detail of a standard bolometer, but I think this is great for houses. It’s not like you’re looking for the hot wire in a wire bundle.

  5. fartface says:

    They are not that expensive anymore….

    Dirt cheap at $2500.00 Hell my prosumer HD camcorder cost more than that.

  6. Stan says:

    I have always wanted one of thees. This is cool – or hot – depends :)Perhaps with some lenses (ZnSe only ones that would work) and Niplow scanning disk arraignment, the resolution could be improved.

  7. Doktor Jeep says:

    Very nice

  8. bemis says:

    It’s probably worth pointing out that you can rent a nice $2000 professional version with SD card capability from Home Depot for about $50 for a 24-hour period…

    For smaller spot work I have successfully used non-contact thermometers to locate cold spots on walls near windows/doors, as well as floor/ceiling areas, to pinpoint where wind/air must be sneaking in.

  9. anon says:

    I had to hunt around for it on the pages linked, but apparently this is the hardware setup in question: The sensor is an MLX90620, connected to an Arduino, which is in turn connected to a wifi breakout board. The iPhone gets the sensor data via wifi and overlays it with the live video feed.

  10. Hirudinea says:

    Nice, remove the IR filter from your iPhone (or Android phone) and you really will have Predatorvision.

  11. Mardaso says:

    Nice set-up.
    Working on the same:

    Discussion about this sensor on XDA:

  12. asdf says:

    Evaluation Board for MLX90620 Temperature Array:|MLX90620|1|,Ny:True,Nea:True

  13. Haku says:

    During one of my searches for DIY thermal imaging stuff I found a project someone did, it was a ‘thermal torch’ with an IR temperature sensor and a bunch of bright red,green & blue LEDs.
    The idea was whatever you pointed the torch at the LEDs would shine coloured light onto it showing wether it was hot, warm or cold.

    If I can find the page again I’ll link it here.

  14. Daniel says:

    I believe this is the original blog site:

  15. HC says:

    Since this data is being fed into software on the smartphone, there are loads of applications for this. One that springs to mind would be pointing it at your breadboard, where it could signal an alert if a component became hot enough to burn skin.

  16. nes says:

    That’s very neat. I like that.

    I suggest upping the frame rate a bit to say 30fps to be closer to the iphone camera and then try implementing motion tracking in software. That way he could possibly build up a more detailed heat map by sweeping the device around a little instead of holding it steady.

  17. A5sd says:

    If the response time was adequate, couldn’t you vibrate the sensor and monitor its position to drastically increase resolution?

  18. Samtronic says:

    An idea on how to make a cheap thermal imaging sensor:

    Working prototypes got made, but it seems that it didn’t get any further.

  19. Angros47 says:

    Another interesting idea is using thermochromic liquid crystals:

  20. FrankenPC says:

    First off, kudos to a really cool idea well implemented. That is really clean.

    I’ve looked into that sensor and my main gripe with it is not the resolution, it’s the refresh speed. If it could update around 20-30 times a second, I would be using it for all kinds of things. As it stands it’s possible to get stand alone units with 100×100 pix 5-10 hz on ebay for around 500$. Real time gray scale units for around 900$. (broken high end ones for even cheaper)

    For those of you who have never used a highly sensitive thermal imager before, I found an unforeseen useful side effect: the worlds most expensive stud finder. That’s right, the wood support beams can be seen pretty clearly through the wall board. It’s pretty awesome when determining where to install shelf brackets, etc.

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