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DIY-Thermocam: A low-cost thermal imager based on the FLIR Lepton sensor

diy-thermocam.net

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Re: DIY-Thermocam: A low-cost thermal imager based on the FLIR Lepton sensor

#31

Post by rittermax »

oneplane wrote: post #27

It's pretty cool. But note that from an end-user perspective you're getting a Flir Lepton 3.5 thermal camera for $522.99. A Flir TG165-X does mostly the same stuff for a much lower price (and half the horizontal and vertical resolution due to the lower end lepton). But the TG doesn't allow you to hack it, and this project does. A Flir ONE (2nd Gen) does almost the same, for about half the price. But again, not as hac…

Agree. I think it depends on the use-case (and a personal interest in open-source and DIY stuff) which solution is the best.

For example with the open serial protocol of the DIY-Thermocam, you can build your own software applications in Python, Typescript, etc. to cover use-cases that are not part of any standalone solution (https://www.diy-thermocam.net/docs/serial/).

And if you are familiar with Arduino microcontrollers, you can change the firmware as you wish and extend it with new capabilities as well (https://github.com/maxritter/diy-thermocam/tree/master/firmw...).

Re: DIY-Thermocam: A low-cost thermal imager based on the FLIR Lepton sensor

#32

Post by 13of40 »

RobotToaster wrote: post #24
OJFord wrote: post #7

Can you make a slightly crappier version with a much cheaper visible spectrum sensor? I don't know much (obviously) about how they work, but intuitively it would seem a bit weird to me if they just happened to be restricted to exactly the same part of the spectrum as our eyes as a hardware limitation. Can you ignore data about visible red and higher in firmware, and get a thermal image that's obviously not as good as…

If you remove the infrared blocking filter (hot mirror) from many digital cameras, they can see very shortwave near infra red. Forward looking infrared (FLIR)[0] cameras detect long wave infrared, which is what you need for a "thermal" camera. [0] quite what is "forward looking" about them I don't know

"forward looking"

Old sensors worked like side-scanning sonar, where the image is built up one row at a time as your vehicle moves forward. Forward looking means you can just point it somewhere and take a 2D picture.

Re: DIY-Thermocam: A low-cost thermal imager based on the FLIR Lepton sensor

#33

Post by DoingIsLearning »

rittermax wrote: post #25
DoingIsLearning wrote: post #17

Earlier quoted context omitted.

It still isn't affordable. You can get a phone add-on from FLIR for $180/$200. This is a great exercise in building stuff for yourself but not affordable at all. The thousand of dollars cameras you refer to have very high resolutions which are really not the use case for the curious maker that would be interested in such a project.

The DIY-Thermocam also works with the FLIR Lepton2.5, which is slightly cheaper (but has a lower resolution): https://store.groupgets.com/products/flir-lepton-2-5 But I agree that the price might be too steep for the curious maker who does not have a serious use-case that satisfies the investment on the long run

Kudos for this project though. It is important to have well documented open source hardware in a as many field applications as possible.

This is still a great project for a lot of educational use cases e.g. thinking of universities and high schools who want to envolve students in the build process.

Re: DIY-Thermocam: A low-cost thermal imager based on the FLIR Lepton sensor

#34

Post by rittermax »

sitkack wrote: post #23
dpflan wrote: post #9

Earlier quoted context omitted.

Do you know of a good, lower-price substitute?

You can get MLX90640 based devices for under $50, but the resolution is 32x24 instead of 160x120 https://www.melexis.com/en/product/MLX90640/Far-Infrared-The...

Indeed, the predecessor of the DIY-Thermocam was called Cheap-Thermocam and built on the MLX90614. If you want to have a look, it is still available via the Wayback Time Machine (has been released 10 years ago): https://web.archive.org/web/20121128040746/http://www.cheap-...

Re: DIY-Thermocam: A low-cost thermal imager based on the FLIR Lepton sensor

#35

Post by oneplane »

rittermax wrote: post #31
oneplane wrote: post #27

It's pretty cool. But note that from an end-user perspective you're getting a Flir Lepton 3.5 thermal camera for $522.99. A Flir TG165-X does mostly the same stuff for a much lower price (and half the horizontal and vertical resolution due to the lower end lepton). But the TG doesn't allow you to hack it, and this project does. A Flir ONE (2nd Gen) does almost the same, for about half the price. But again, not as hac…

Agree. I think it depends on the use-case (and a personal interest in open-source and DIY stuff) which solution is the best. For example with the open serial protocol of the DIY-Thermocam, you can build your own software applications in Python, Typescript, etc. to cover use-cases that are not part of any standalone solution ( https://www.diy-thermocam.net/docs/serial/ ). And if you are familiar with Arduino microcont…

I think that it is where this project shines; the accessibility. After building and setting it up it can work stand-alone, but also integrated with any project you are already familiar with (within reason).

Re: DIY-Thermocam: A low-cost thermal imager based on the FLIR Lepton sensor

#36

Post by rittermax »

I know that affordable is a flexible term and the DIY-Thermocam might still be too expensive for some folks.

The predecessor of this device was called "Cheap-Thermocam" (https://web.archive.org/web/20121128040746/http://www.cheap-...) and it used a single-spot MLX90614 sensor to create a thermal image by combining the measurements.

Although the project is now 10 years old, there is a good writeup if anybody wants to build it: https://www.instructables.com/Thermal-Camera/

Re: DIY-Thermocam: A low-cost thermal imager based on the FLIR Lepton sensor

#38

Post by rittermax »

sitkack wrote: post #29
rittermax wrote: post #2

The DIY-Thermocam V3 is a low-cost, do-it-yourself thermal imager, based on the popular radiometric FLIR Lepton sensor and an open-source ecosystem. It gives private persons, educational institutes and companies access to a portable, affordable and customizable thermal imaging platform that is based on open-source software and hardware. It is constructed as a self-assembly solution, that can be build at home by only…

Your parts list is missing the actual Lepton imager, https://www.diy-thermocam.net/docs/partlist/ I know it is on the other group gets page. I was not able to find the BOM in the GH repo. This would be a useful addition. It looks like in an earlier version you had a visible camera as well, what was the choice in removing it? I take it the device does not present itself as a web cam?

Thanks for mentioning the missing parts. It was so obvious that I missed it, they are now added ;)

You are right, Version 2 had a visual camera. However, the alignment between LWIR sensor and visual camera was never perfect and most people only used the thermal image feature OR they took photos with a smartphone and combined it in the Thermal Analysis Software (ThermoVision) on the PC later on. That's why I decided to remove the visual camera for V3 to reduce building complexity and costs.

Re: DIY-Thermocam: A low-cost thermal imager based on the FLIR Lepton sensor

#39

Post by hansvm »

atoav wrote: post #19
rtomanek wrote: post #6

$523 total? That's not my definition of affordable.

Depends. 523 USD for a car is suspicously cheap. 523 USD for a mediocre sandwich is outrageously expensive. Context matters and thermal imaging is very expensive usually.

Separately, there's a notion of purchases large enough you have to plan for them. $523 is a few weeks of pay for some people even in the US. The headline is set up to suggest a low-cost (because it's DIY) relative to the status quo of devices an average student couldn't really buy to tinker with. The result is more expensive than an off-the-shelf thermal camera I bought awhile ago without substantially better features (other than tinkerability).

Re: DIY-Thermocam: A low-cost thermal imager based on the FLIR Lepton sensor

#40

Post by sitkack »

kragen wrote: post #28
sitkack wrote: post #21

Earlier quoted context omitted.

The sensor itself is 160. There is no getting around that.

you could make your own thermal sensor, which is what i thought the article was going to be about from the title this is a bit like 'i made a working, drivable car from scratch using only basic hand tools, raw materials, and a 2005 honda civic' or 'i built my own operating system around the linux kernel'

That would be really neat, but I haven't seen anyone even make a CMOS imager on SKY130.

https://github.com/google/skywater-pdk

One could make an array of thermopiles, like the hacker that made their own imager out of discrete diodes (digiOBSCURA) . But each pixel would cost $7.

https://www.digikey.com/en/products/detail/excelitas-technol...

One might be able to make an array of thermistors (possibly with active cooling using a peltier) like the diycamera (digiOBSCURA) below. Might be an application of combining many RC oscillators in a tree and recovering the signal with an FFT. I have a gut feeling this is possible, but haven't show it. Isn't this the same as or similar to your keyboard multiplexer design?

https://www.digikey.com/en/products/detail/panasonic-electro...

https://github.com/IdleHandsProject/diycamera (digiOBSCURA)

One could experiment with microbolometers on tinytapeout. https://elicit.org/search?q=cmos+microbolometer

https://tinytapeout.com/

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