A Hot Printer For Cool Selfies

Randomly buying some hackable gadgets just because they are cheap and seem potentially interesting for future projects is something that most of us can relate to. It also happened to [fruchti] when he bought five thermal printer modules without any specific purpose for them in mind. It was not until several years later that he put them to good use for his inverse thermal camera project.

The name perfectly summarizes the device’s function which is to convert images to heat instead of the other way around. To put it in a less cryptic manner, [fruchti] built a selfie camera that instantly prints out pictures on thermochromic paper. The project would have been easy to implement on a Raspberry Pi but instead, he chose a more minimalist approach by using an STM32 microcontroller. This involved some challenges because the MCU didn’t have enough RAM to store an entire frame and the camera module came without a FIFO buffer. To capture and store the image data [fruchti] applied a line-by-line dithering algorithm which is described in detail in his accompanying blog post while the corresponding code is available on GitHub. Even though the case was improvised from scrap PCB materials the finished device still looks great. In particular, the fuse holders that are being used to hold the paper roll make it almost steampunk.

Naturally, this is not the first time we have seen thermal printers being used for instant picture taking and it probably won’t be the last.

12 thoughts on “A Hot Printer For Cool Selfies

    1. You can put a flashy website up, but that’s just prolonging the effect. That image will never go away. It’s the hello world of digital images. I don’t know why it bothers her quite that much, considering it’s just the portrait of her face that has been widely used. They say you truly die the last time somebody remembers you. She will be remembered forever, because she left a legacy to the digital world. At least, that’s how I would spin it.

    2. Lena herself has said she think it’s surprising that her photo is being used, but also that she’s not sure what the fuss is about or why people would find her picture offensive, so there’s that to consider too.

    3. Shame the discussion about the actual the project has been derailed by this.
      But I am fascinated how people manage to turn the use of this image into the cornerstone of why certain groups or people are underrepresented in tech.
      This world is going slowly insane.
      Let’s use images of red foxes in the future, they are certainly more fun!

    4. Not sure how I feel about this. Lena, like the Utah Teapot, is a standard reference. She’s not going to go away. I would perhaps feel differently if the entire image was used, but the crop generally used is not offensive. And to claim that the use of Lena’s image as a reference is somehow demeaning or discouraging to women in tech seems like a bit of a stretch.

      A bit of a “tempest in a teapot”, perhaps?

    5. I had no idea who she was, or the context of the original photo (pR0n).
      And I could have gone through life without knowing.
      But thanks to the “woke” video on your link, I wonder how many women/girls in tech are snowflakes looking for any excuse to be triggered.

    6. New to me knowledge there, which I like. Now my silly side feels like using her image in a project but with a fake mustache to obscure her identity. Just kidding! Don’t have the skills (yet) to accomplish such foolishness!

      Cool video. Cool project. Win:win.

    7. Thanks for the link! I was aware of the origin of the picture, but not of Lena’s call to retire it. I had always viewed it from a technical angle and chose it here for its recognisability, without thinking the implications through completely.

      I wanted to swap the lens for a more wide-angle one anyway, so I’ll just replace this photo as well.

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