Hacklet 47 – Thermal Imaging Projects

Thermal imaging is the science of converting the heat signature of objects to an image visible to humans. Everything above absolute 0 gives off some heat, and thermal imagers allow us to see that – even if there is no visible light in the room. Historically, thermal imaging systems have been large and expensive. Early systems required liquid nitrogen cooling for their bolometer sensors. Recent electronic advances have brought the price of a thermal image system from the stratosphere into the sub $300 range – right about where makers and hackers can jump in. That’s exactly what’s happened with the Flir Lepton module and the Seek Thermal camera. This week’s Hacklet is all about thermal imaging projects on Hackaday.io!

We start with [Pure Engineering] and Flir Lepton Thermal Camera Breakout. Flir’s Lepton thermal camera created quite a stir last year when it debuted in the Flir One thermal iPhone camera. The Lepton module used in the Flir One is a great standalone unit. Interfacing only requires an I2C interface for setup and an SPI interface for image data transfer. Actually using the Lepton is a bit more of a challenge, mainly because of its packaging. [Pure Engineering] made a simple breakout board which makes using the Lepton easy. It’s also breadboard compatible – which is a huge plus in the early phases of any project.


grideyeNext up is [AKA] with GRID-EYE BLE-capable thermal camera. This project is a Bluetooth low energy (BLE) thermal camera using Panasonic’s Grid-EYE 64 pixel thermal sensor. 64 pixels may not sound like much, but an 8×8 grid is enough data to see quite a bit of temperature variation. If you don’t believe it, check the project page for a video of [AKA] using Grid-EYE’s on-board OLED display. Grid-EYE was a Hackaday Prize 2014 semifinalist, and we featured a bio on [AKA] last year. The only hard part with building your own Grid-EYE is getting the sensor itself. Panasonic doesn’t sell them to just anyone, so you might have to jump through a few hoops to get your own.


pylepton[Kurt Kiefer] brought the FLIR Lepton to the Raspberry Pi with pylepton video overlay. This project uses the Lepton to overlay thermal data with images captured by the Raspbery Pi camera module. The Lepton interfaces through the I2C and SPI ports on the Pi’s GPIO pins. The results are some ghostly images of black and white thermal views over color camera images – perfect for your next ghost hunting expedition!  The entire project is implemented in Python, so it’s easy to import and use pylepton in your own projects. [Kurt] even gives an example of capturing an image with just 5 lines of code. Nice work, [Kurt]!



wificamFinally we have [Erik Beall] with WiFi Thermal Camera. [Eric] is using an 82×62 diode array to create thermal images. Unlike microbolometer sensors, diode/thermopile sensors don’t need constant calibration. They also are sturdier than Microelectricomechanical System (MEMS) based devices. This particular project users an array from Heimann Sensor. As the name implies, the sensor is paired with a WiFi radio, which makes using it to capture and display data easy. [Erik] must be doing something right, as WiFi Thermal Camera just finished a very successful Kickstarter, raising $143,126 on a $40,000 initial goal.

Are you inspired? A thermal imager can be used to detect heat loss in buildings, or heat generated by electrical faults – which means it would be a great project for the 2015 Hackaday Prize! If you want to see more thermal imaging projects, check out the thermal imaging projects list!

That’s it for this week’s Hacklet, As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

Long Exposure Thermal Photography

For apparently inexplicable reasons, the price of thermal imaging cameras has been dropping precipitously over the last few years, but there are still cool things you can do with infrared temperature sensors.

A few years ago – and while he was still writing for us – [Jeremy] came across an absurdly clever thermal imaging camera. Instead of expensive silicon, this thermal camera uses a flashlight with an RGB LED, a cheap IR temperature sensor, and a camera set up to take long exposures. By shining this flashlight/IR sensor around a dark room, a camera with a wide-open shutter can record color-coded thermal images of just about anything.

Since then, an interesting product appeared on the market. It’s the Black & Decker TLD100 Thermal Leak Detector, and it’s basically an infrared thermometer and LED flashlight stuffed into one neat package. In other words, it’s the exact same thing we saw two years ago. We’d like to thank at least one Black & Decker engineer for their readership.

[Jeremy] took this cheap, off-the-shelf leak detector and did what anyone would do after realizing where the idea behind it came from. He set up his camera, turned off the lights, and opened the shutter of his camera. The results, like the original post, don’t offer the same thermal resolution as a real thermal camera. That doesn’t mean it’s still not a great idea, though.

Real-Time Thermal Projection Saves Your Tastebuds from the Hot Stuff

With another wave of holiday parties about to land on our doorstep, we still haven’t found a great way to stop scalding our tongues each time [Uncle Dave] pours us an enticing cup of boiling cocoa.

Thankfully, [Ken] has both you and your holiday guests covered with a clever trick that takes the data from a FLIR ONE and projects a heat profile onto the surface it’s observing. Here, [Ken] has superimposed his FLIR ONE data onto his kitchen table, and he’s able to visualize 2D heat profiles in near-real-time.

If you haven’t started quantifying yourself recently (and what are you waiting for?), the FLIR ONE is yet another opportunity to help you become more aware of your surroundings than you are now. It’s a thermal camera attachment for your iPhone, allowing you to see into the infrared band and look at the world in terms of heat. We’ve covered the FLIR ONE before, and we’ve seen ways of making it both clearer and more hacker-friendly.

As we tip our hats to [Ken], we’d say he’s a generous fellow. This hack is a clever inversion of the normal use case where you might whip out your FLIR-ONE-enabled iPhone and warn your cousins not to try the hot chocolate for a few more minutes. With [Ken’s] solution, the data is right there on your condiments and in plain sight of everyone, not just for you with your sweet, Star-Trek-augmented iPhone.

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Simple Thermal Imager with a Lepton Module

[Andrew] designed a simple thermal imager using the FLIR Lepton module, an STM32F4 Nucleo development board, and a Gameduino 2 LCD. The whole design is connected using jumper wires, making it easy to duplicate if you happen to have all the parts lying around (who doesn’t have a bunch of thermal imaging modules lying around!?).

The STM32F4 communicates with the Lepton module using a driver that [Andrew] wrote over a 21MHz SPI bus. The driver parses SPI packets and assembles frames as they are received. Images can be mapped to pseudocolor using a couple different color maps that [Andrew] created. His code also supports min/max scaling to map the pseudocolor over the dynamic range present in the image.

Unfortunately the Lepton module that [Andrew]’s design is based is only sold in large quantities. [Andrew] suggests ripping one out of a FLIR ONE iPhone case which are more readily available. We look forward to seeing what others do with these modules once they are a bit easier to buy.

THP Hacker Bio: AKA

Thermal imaging cameras are the new hotness when it comes building DIY tools that are much less expensive than their commercial counterparts. [Mike Harrison] built a very high-resolution version from Flir’s Lepton module, but an IR temperature sensor and a servo can also create a decent image. [AKA] played around with some of these thermal imaging modules, but found them a little hard to interface. Panasonic’s Grid-EYE module, however is reasonably cheap as far as thermal imaging devices go, and can be read over an I2C bus.

[AKA]’s entry for the Hackaday Prize, the GRID-EYE Thermal Camera is one of two Prize entries that survived the great culling and made it into the quarterfinalist round. [AKA] was kind enough to sit down and do a short little interview/bio with us, available below.

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A Breakout Board for a Flir Lepton

Thermal imaging cameras are all the rage now, and one of the best IR cameras out there is Flir’s Lepton module. It’s the sensor in the FLIR ONE, a thermal imaging camera add-on for an iPhone. Somewhat surprisingly, Flir is allowing anyone to purchase this module, and that means a whole bunch of robotics and other various electronics projects. Here’s a breakout board for Flir’s Lepton.

Electron artisan [Mike] recently got his hands on a FLIR ONE, and doing what he does best, ripped the thing apart and built the world’s smallest thermal imaging camera. Compared to professional models, the resolution isn’t that great, but this module only costs about $250. Just try to find a higher resolution thermal imager that’s cheaper.

With this breakout board, you’ll obviously need a Lepton module. There’s a group buy going on right now, with each module costing just under $260.

The Lepton module is controlled over I2C, but the process of actually grabbing images happens over SPI. The images are a bit too large to be processed with all but the beefiest Arduinos, but if you’re thinking of making Predator vision with a Raspi, BeagleBone, or a larger ARM board, this is just the ticket.

You can check out some video made with the Lepton module below.

This is also project number 3000 on hackaday.io. That’s pretty cool and worthy of mention.

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A Better, Cheaper Smartphone Thermal Imager


For the last few years, the prices of infrared thermal imaging devices have fallen through the floor, down from tens of thousands of dollars a decade ago, to just about a grand for a very high-resolution device. This dramatic drop in price was brought about by new sensors, and at the very low-end, there are quite a few very inexpensive low resolution thermal imaging devices.

The goal now, it seems, is to figure out some way to add these infrared devices to a smartphone or tablet. There have been similar projects and Kickstarters before, but [Marius]’s entry for The Hackaday Prize is undercutting all of them, and doing it in a way that’s far, far too clever.

Previous ‘thermal imagers on a smartphone’ projects include the Mu Thermal Camera, a $300 Kickstarter reward that turned out to be vaporware. The IR-Blue is yet another Kickstarter we’ve seen, and something that’s actually shipping for about $200. [Marius] expects his thermal imager to cost just $99. He’s getting away with this pricing with a little bit of crazy electronics, and actually designing a minimum viable product.

Both the Mu Thermal Camera and the IR-Blue communicate with their smartphone host via Bluetooth. [Marius] felt radio modules were unnecessary and inspired by the HiJack system where low-power sensors are powered and read through a headphone jack, realized he could do better.

Always the innovator, [Marius] realized he could improve upon the HiJack power harvesting solution, and got everything working with a prototype. The actual hardware in the sensor is based on an engineering sample of the Omron D6T-1616L IR array module, a 16×16 array of IR pixels displaying thermal data on a portable device at 4 FPS.

It’s interesting, for sure, and half the price and quadruple the resolution of the IR-Blue. Even if [Marius] doesn’t win The Hackaday Prize, he’s at least got a winning Kickstarter on his hands. Video of the 8×8 pixel prototype below.

SpaceWrencherThe project featured in this post is an entry in The Hackaday Prize. Build something awesome and win a trip to space or hundreds of other prizes.

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