DIY Thermal Imaging Infrared Camera

Hello!

I'm always looking for new Projects for my physics lessons. Two years ago I came across a report on the thermal sensor MLX90614 from Melexis. The best one with just 5° FOV (field of view) would be suitable for a selfmade thermal camera.

To read out the temperature I use an Arduino. In the internet you can find many descriptions about reading out the datas (f.e. https://learn.adafruit.com/using-melexis-mlx90614-non-contact-sensors/wiring-and-test).

What you have to do creating a whole thermal picture is to change the alignment of the sensor like the electron beam in an old TV. Those z-tracks can be realised with a two-servo-mount.

Here you can find help, how to control servos with an arduino: http://playground.arduino.cc/ComponentLib/Servo

So you will need:

• two servo (http://www.ebay.com/itm/Pan-Tilt-Wh-Best-Platform-Kit-Anti-Vibration-Camera-Mount-for-Aircraft-NO-SERVO-/321752051406?hash=item4ae9eaaece)
• voltage control for the servo (I realised it with a LM317, but maybe you can use just a normal, fixed 5V-supply)
• Arduino uno or similar
• MLX90614 with 5° FOV (the less FOV the sharper your Image, http://www.ebay.com/itm/Melexis-Mlx90614esf-dci-Ds-Digital-Non-contact-Infrared-Temperature-Sensor-/151601500838?hash=item234c2752a6)
• button
• some resistors
• cable, Wood, screws ...

Step 1: The Structure

The thermal camera just consists of the arduino uno, which is reading the temperature and controlling the two servos. The algorithm is quite simple: Read the temperature and go one servo step further ...

To start the measurement I use a button. With the program teraterm you can read the data: x, y, temperature

Those three rows are saved as a file, which can be finally visualized with the freeware gnuplot.

Step 2: The Software

With the arduino you can control the two servos and read the temperatures from the Melexis sensor. Those values (x-position, y-position and temperature) are sent to the computer, where you can see and save them with teraterm. With gnuplot you can make a coloured picture of your temperature-array.

Step 3: The Results

Here you can see some thermal Pictures (cooktop, naked human body [me ;-)], candle)

They consist of 40x40 Pixels but it's up to you, which number of pixels you program. The more Pixels the longer the exposure takes. You can try to minimize the exposure time for on Pixel, but it will still last a certain time..

Maybe you want to take a look at my other Projects:

https://www.youtube.com/user/stopperl16/videos

more physics projects: https://stoppi-homemade-physics.de/

Thank's for your time ;-)

Comments

[whumly1223]

Hi thanks for your sharing. Can I use MLX90614 BAA or BCC if I just measure the temperature of the close objects? But I didn’t find the FOV of these two sensors, is it larger than DCI?

[stoppi71]

Hello! The last charcter is for the field of view. A = Standard (about 100°), C = 35° FOV, F = 10° FOV and I = 5° FOV.
Therefore I wouldn't recommend the BAA, because it has the standard FOV without any focusing lens. The BCC has 35° FOV. It depends which resolution you want to have. For a sharp image a smaller FOV is better. Good luck, stoppi

[whumly1223]

Thanks so much for your reply and kind explanation. I want a high resolution actually, I want to measure the temperature difference between the wet and dry, and the distance between the sensor and the object might be 5-10cm, would you recommend me DCI? If so, is this what you use? https://www.ebay.de/itm/124256857864
I also found this https://www.banggood.com/de/CJMCU-MLX90614-DCI-Human-Body-Infrared-Thermometer-Non-contact-Thermometer-Serial-Output-Module-p-1696131.html?rmmds=search&cur_warehouse=CN
I am wondering which one I shoud choose,I would be so appreciated if you could give me some suggestions.
Thank you!

[stoppi71]

Hi!
Because you want higher resolution I'd recommend the DCI-type. But the offer from banggood is much too expensive. I'd buy one from ebay like in the link for about 60 USD. I bought my MLX90614ESF-DCI in 2012 for 60 Euro. But I inform you that for 60 USD you nearly get a MLX90640-sensor, which has a 32x24 pixel array. Take a look at my instructables: https://www.instructables.com/id/Infrared-Thermal-Imaging-Camera-With-MLX90640-and-/

[whumly1223]

Oh, thank you so much! I am a beginner about this, so could you please briefly tell me the advantage or the difference of this new MLX90640? For example the advantage of one more pixel. Besides, I saw one FoV is 110°x75° (MLX90640BAA) and the other with 55°x35° fov (MLX90640BAB), bu actually I am still confused about what does 110°x75° or 55°x35° mean and the difference between 110°x75° and the 5° FOV of DCI-Type..Do you know where I can learn this basic knowledge? Thank you so much!

[stoppi71]

The MLX90614 has just 1 pixel and the field of view of this one pixel is f.e. 5° for the DCI model.
The MLX90640 has 32x24 = 768 pixel. If the field of view for the whole sensor is 110°x75°, then one single pixel has a field of view of 110/32 = 3,4°/pixel (or 75/24 = 3.1°/pixel). Therefore one pixel of the MLX90640 has a smaller FOV (= higher resolution) than the 5° FOV version of the MLX90614...

[whumly1223]

wow! Thank you sooooo much! I understand ! Then MLX90640 is best considering its resolution. But I saw its accuracy is 1°C. But I am afraid it cannot detect the temperature difference in my target area. I think I need one with 0.1°C accuracy. I think maybe I still need MLX90614 DCI considering this? What do you think? One more question, I saw you used ILI9341 display to visualize the temperature, do you think is it possible to wirelessly send the temperature data to the computer and visualize it on the computer?

[francismarkk]

hello can you give me the source code for the two programs please? thank you.

[stoppi71]

Hello!
I've added the two arduino-programs and some further informations. Good luck ;-)

[francismarkk]

Also, can you update the ebay links please? The items were already deleted.

[francismarkk]

Thank you very much! Is it the full and complete step?

[Baasil Biniyamin]

Can i use this one "XCLUMA MLX90614 contactless tempareture sensor module GY-906

[stoppi71]

No, you'll need the model MLX90614-DCI, which costs about 30 USD

[Baasil Biniyamin]

https://www.amazon.in/xcluma-MLX90614-Contactless-...

[AbhishekY30]

what software are you using for showing results???/

[stoppi71]

The freeware gnuplot

[Happy_Mad_Scientist]

How far is range? I though maybe a point and shoot temp sensor like in a hardware store. And if I am running an IR flashlight will it affect the sensor? Thanks for help.

[stoppi71]

thermal Imaging infrared cameras don't have a Limit concerning their range. The only Problem is, that the detected area increases with increasing distance. For example you can measure the temperature of the sky...

The opening-angle is at least 5° with those MLX-sensors...

IR-light could indeed affect the sensor, because it's measuring the incoming IR-light...

[ev2driver]

Good. Something worth a try ! I suspecr you learned more of what is shown in the IR pic.

[RajM41]

Nice