FLIR ONE Pro – Thermal Imaging Camera for your smartphone

Flir are the standard when it comes to thermal imaging. As an electronics engineer, I have used their products for many years. From the big and clunky gun style cameras to the now ‘digital camera’ styled C1, I have tried quite a few products from their range. They introduced the FLIR One, which plugs into your smartphone, allowing you to take a thermal camera with you everywhere. Now, with the FLIR ONE Pro, you have more resolution and an even better performance.

FLIR ONE Pro – Features

  • Powerful thermal imaging camera lets you find hidden electrical problems, energy loss, water damage, and other heat-related issues
  • Free FLIR One app features automated reporting, spot meters and lots of free real-time tips and tricks!
  • FLIR ONE allows you to see and measure temperature differences between -4°F and 752°F (-20° to 400°C) accurately and from a safe distance
  • MSX and Vivid IR enhanced image processing and video capabilities give you the sharpest mobile thermal imaging performance. Ever.
  • One Fit adjustable connector allows for use with compatible protective cases

In the box

  • FLIR ONE Pro
  • USB C to USB cable
  • Protective case
  • Documentation

Why get a thermal camera?

At around £399, it isn’t the kind of thing you will go and buy just for the heck of it. However, a thermal camera has applications that are very useful. I work as an engineer, and a thermal camera is the easiest way to find out what is misbehaving on a PCB. If you are a plumber, you can easily find out how well the water or heat is flowing by looking at it through this. Similarly, if you find your house to be drafty, just go outside and look at the hotspots. They are the bits that are leaking all the heat out!


The setup is reasonably simple. You install the FLIR One app. Annoyingly, you are forced to create an account before you can use the device. I found this to be unnecessary.

Once you have signed up and logged in, you can plug the device in.

I tried the iOS version. A very good feature is that you can adjust the height of the connector coming out of the device. This means that you can use this with smartphones both with or without cases.

Once plugged in, you start to see a live thermal image. Take thermal images, just like you would with your normal camera.

The device comes with USB C, iOS and Micro USB versions. With the first two, you can have it both facing forward or backwards.


I used this on an iPhone 6. It seems like it relies heavily on the hardware of your phone, as I found the app to be a bit clunky and slow. You can set up various things on it, and see how it looks. Adjust colour gradients, and fix temperature range as needed.

The hardware is very well thought out, but I thought that the app definitely needs an interation or two before it can be perfect.

Overall, it is intuitive and simple, but lacks options to make many changes beyond the obvious.

Sample Images

Best way to see how well it works is to go through some sample images.

We start off with a selfie (of course!).

Notice how you can see the patterns on my shirt. This is because of FLIR’s MSX technology, which is available in rest of their range too. It superimposes the optical image over the thermal, so you can make out what you are looking at. The brighter, the hotter.

From there we move on to a picture of my two cats, huddled together and sleeping.

For this image, I had changed the view to rainbow. Red is hottest, blue the coolest.

Notice how their noses are slightly colder than rest of them.

Here is a picture of a candle. The flame itself appeared black, which I found was ‘out of range’ for the camera. A candle may not feel very hot, but can be quite hot at its centre. Also notice how there is a warm stream coming above it, showing the warmth it gives.

If you focus on the top part, you may notice a slight misalignment between the optical edges and the thermal image. This can happen if you keep the camera too close to your object. This has been observed in other FLIR products too.

As I used the camera more, I found holding my phone upside down gave me the best results. This isn’t unlike how most smartphone cameras are.

Finally, a picture which shows an actual use case, that of a ‘leaky window’.

Notice the red blocks. They are the glass parts of the windows, and sadly they are very red. This shows me that my windows are not very well insulating. This also explains why our downstairs tends to get so very cold in the winter.

This picture is a very good example of how well the MSX technology works. See how easily you can see each brick clearly.


Oh yes, you need to charge this, hence the USB C cable. Annoyingly, the iOS version didn’t come with a lightning port, so you still needed a separate cable to charge it. Battery life was a few hours. I hoped that plugging this in the bottom of the phone, and then putting it on charge will charge the phone too. However, did this not happen.

It also doesn’t take any power from the phone. This is a good/bad thing, depending on your point of view.

More information

More information on the FLIR ONE Pro can be found on the Flir website.

It retails for around £399 and can be bought from various online retailers, such as Amazon.

In comparison, if you want a cheaper all in one solution, the Flir C2 costs around £500, but offers a lesser thermal imaging resolution.


This is pretty much the only such device that exists for smartphones on the market. The price may be high, but the quality you get is pretty good for any other thermal imaging solution out there.

5 thoughts on “FLIR ONE Pro – Thermal Imaging Camera for your smartphone”

  1. Windows are highly reflective, the red on your image is very likely the detector picking up radiation being reflected by your window from other temperature emitters nearby (you can see your image in the window as an example); not the temperature of the glass. Cover the glass in an emissive material in order to obtain a truer indication 🙂

    • Hi Chris,
      Absolutely! IR is very reflective in terms of glass. I could easily see my reflection in most windows. However, this one was just all red. I do know there is a leak in the double glazing so I wasn’t surprised.
      Thanks for the tip!


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