Raspberry Pi Tracks Humans, Blasts Them With Heat Rays

Given how long humans have been warming themselves up, you’d think we would have worked out all the kinks by now. But even with central heating, and indeed sometimes because of it, some places we frequent just aren’t that cozy. In such cases, it often pays to heat the person, not the room, but that can be awkward, to say the least.

Hacking polymath [Matthias Wandel] worked out a solution to his cold shop with this target-tracking infrared heater. The heater is one of those radiant deals with the parabolic dish, and as anyone who’s walked past one on demo in Costco knows, they throw a lot of heat in a very narrow beam. [Matthias] leveraged a previous project that he whipped up for offline surveillance as the core of the project. Running on a Raspberry Pi with a camera, the custom software analyzes images and locates motion across the width of a frame. That drives a stepper that swivels a platform for the heater. The video below shows the build and the successful tests; however, fans of [Matthias] should prepare themselves for a shock as he very nearly purchases a lazy susan to serve as the base for the heater rather than building one.

We’re never disappointed by [Matthias]’ videos, and we’re always impressed by his range as a hacker. From DIY power tools to wooden logic circuits to his recent Lego chocolate engraver, he always finds ways to make things interesting.

23 thoughts on “Raspberry Pi Tracks Humans, Blasts Them With Heat Rays

  1. Awesome! Now add a similar for bugs and critters that uses a laser and can identify humans and pets and not fry them. I had commented on EEVblog I think… I forget… noting to use a distance finder so the tuned laser for the target most optimally discharges on the target. Awesome as a heater for sure as is!

    1. Been wondering about using a lock-in amplifier too and visually stimulating… the beam forming with a lock-in amplifier thing started with this article:
      https://www.instructables.com/id/Seeing-Sound-Waves-Bug-Sweeping-Robots-for-Augment/

      …then further refined with this article:
      https://hackaday.com/2017/09/27/lock-in-amplifiers/

      The laser thing goes back to reading “Lasers: The Light Fantastic” back in middle school.

      I like the simplicity of the pulley mechanism build also. I so had a “damn… that’s &%!ing easy” moment. I was thinking adhering to the disc and just having teeth on teeth for the sat finder RDF kit that’s still floating around never land… about as bad as the telescoping yagi build.

    1. If you watch many of his videos you would find out that he likes to save money. He finds wood and furniture for free. He will fix and reuse before buying new. His taste in furniture has nothing to do with his skill as a engineer/woodworker.

  2. Seems quite useful. I would buil one for myself.
    I wonder if OpenCV can be used to recognize a human and distinguish ti from everything else.
    You could apply something similar to lighting.
    I would love to see a future with heatguns tracking you while you walk…

    1. Yeah… I think it’s all about the training set and the algorithm used. Do a Google search on facial recognition or really any image recognition. Basically, mainly the more data to train the model… the better the model will perform if the data set is design correctly.
      https://www.pyimagesearch.com/2018/09/24/opencv-face-recognition/

      I’d use a hierarchical cluster analysis in a few different iterations of combinations of settings to see which was more logical with the all the data set. Then build my models targets at 100% concentration with the target materials and the non-target closest materials, or materials, from the hierarchical cluster analysis at 0%.

  3. A much more energy efficient way would be to build a body warmer out of an electric blanket.
    With a few hundred watts you can keep the core of your body so warm that it’ wants to shed the heat, and therefore starts pumping more blood to the extremities which then also stay warm.

    There has been done some real research on this topic for people who need to do fine work in cold environments where gloves are not a viable option and it really works.

    1. Electrically heated work clothing is available from several of the cordless tool manufacturers who seem to be diverging into anything that will sell more overpriced battery packs.

    2. But then you either have to be dragging a cord around, or dealing with batteries.

      A body warmer made out of an electric blanket seems like a bad idea for a wood worker using power tools.

  4. The final test would be to see what happens with a cat also in the room. In theory the cat would learn that it could attract the heater’s “attention” with movement but … that would require movement which isn’t in most cats’ operating system except between 3 and 4 in the morning.

    It might be the first case of feline stuck DO-loop in history.

    1. Nowhere near the first. Our cat has been stuck in a do loop for years – sleep, eat, sleep, annoy the crap out of me at 4:30AM, sleep, lick self, sleep, move slightly, sleep, sleep harder, repeat.

      1. ALL cats are stuck in that one…I was thinking of the internal loop that goes “If I move, the warmz happen. But I can’t move. But warmz are good. But can’t move…etc. etc.”

  5. I remember this technique was actually proposed for a NIST grant as an alternative to space heating about 10 years ago. It could be a low cost solution to heating large, low-occupancy spaces like aircraft hangars and warehouses or even outdoor areas.

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