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Thermal Imaging for Fun and Profit with the FLIR E5

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Hands-on with a most cool (!) FLIR thermal imaging camera.

It's hard to say when I first heard about thermal imaging and I suspect that, like many people, it will have been at some point in the 1990s and in connection with firefighter use. In any case, it conjures up images of somewhat large and unwieldy devices that use liquid helium to cool a detector down to cryogenic temperatures — with a price tag of: if you have to ask, you cannot afford one!

Of course, technology never stands still and thermal imaging cameras can now be had for a fraction of the price they would have cost only a decade ago. They've also become far more convenient and a cooled detector is only really required for certain specialist applications.

We were given a loan of the compact and eminently usable FLIR E5, and in this post we take a look at its main features and include a few obligatory thermal imaging shots.

Kit contents

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The E5 came packaged in a robust protective case and was supplied with a USB charger, USB cable and manuals. A removable rechargeable battery is located inside the grip.

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Controls

As can be seen above the camera has a trigger button, which is used to capture images. There are also four buttons located underneath the screen.

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Pressing the middle button brings up a menu with options for:

  • Settings

  • Image mode

  • Measurement

  • Colour

  • Temperature scale

From the Settings menu it's possible to change key parameters such as the emissivity and reflected temperature for your particular object. For example, a shiny object is likely to emit less radiation but reflect more, and remember that what the camera captures is overall radiation. So for accurate readings these parameters need to be correctly set, but it turns out that there is a simple enough process to do this, which involves the use of scrunched up silver foil as a reference point.

The E5 actually incorporates two sensors: an IR sensor and a visible light camera. The image mode setting allows you to shift between Multi Spectral Dynamic Imaging (MSX), a mode whereby image processing is used to enhance thermal video with visible spectrum light, thermal only, thermal blending, a slightly surreal mode which appears to add thermal highlighting to a visible image, and digital camera mode.

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Thermal MSX image mode

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Thermal mode

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Thermal blending mode

The measurement menu allows you to change between measuring the temperature from a fix point in the middle of the screen, a moving hot spot, a moving cold spot, and no measurement at all.

The colour menu is used to change between iron, rainbow and grey palettes.

Finally, the temperature menu can be used to auto-ranging and locked scale.

Simple enough!

In use

Right, so if you've read this far you're now probably thinking, “This is all very well, but where are all the cool pictures?!” So, here are a few shots. Bear in mind that they're scaled up from 320x240 and so they are not quite as sharp as when viewed at the native resolution.

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Above can be seen the view over the town of Hebden Bridge.

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Trees look pretty, as anyone who has done photography with infra-red film would expect!

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Cats on the other hand look pretty strange...

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The challenge is that it's hard to maintain focus when a previously invisible world has been revealed to you. But in any case, I managed to after a little while and above can be seen a slightly more technical thermal image, of the diesel engine in an old Land Rover. It hadn't been running long, but the turbo appears to be nicely warming up and at >60C after 5 or 10 minutes.

As it happens, the temperature sender and dashboard gauge in the Land Rover are mismatched, so it always reads in the red and I've worried that it may be overheating and I wouldn't know. So I guess I best take it for a good run and make the most of the camera before I have to send it back!

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And here is the radiator. Guess which side the water enters?

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Finally, a shot that is a much more on topic and that is of inside the Novena open hardware laptop. Here the Freescale quad-core ARM SoC can clearly be seen centre of frame, situated beneath a small heatsink and generating far more heat than anything else on the board.

First impressions

I need a thermal imaging camera. Honestly. It's one of those things that I've often thought it could be useful to have, and obviously a great deal of fun too — but hardly a necessity. However, playing around and having fun imaging random things aside, it's become apparent just how useful it would be when we're designing enclosures and selecting fans and heatsinks etc. for projects.

Sure, you can touch an IC to see if it feels a little too hot, you can attach self-adhesive thermometer strips to devices and blast boards with freezer spray. But quite frankly, this all takes on a sense of the archaic once you've spent any time at all with a thermal imaging camera. And being the slightly paranoid sort when it comes to such things, I suspect that I'll sleep a lot better at night if I've actually seen where heat builds up and is dissipated, and are able to easily ascertain the temperature at any point across an assembly and confirm that the correct design decisions were made.

Get your hands on a Flir E5 

Andrew Back

Thermal imaging can be very useful for identifying changes in temperature. We decided to put this to the test and undertook a study to understand what happens to our bodies when we consume chillies. Staggeringly, the body temperature of our guinea pig increased by 4 degrees!

Open source (hardware and software!) advocate, Treasurer and Director of the Free and Open Source Silicon Foundation, organiser of Wuthering Bytes technology festival and founder of the Open Source Hardware User Group.