Checking for heat leaking out of your house? How about people counting in a business for occupancy? These are perfect uses for the FLIR Lepton FS – when you need thermal imaging but don’t need radiometry data.
Why Pick the FLIR FS?
Look, we all love the Teledyne FLIR Lepton 3.5 camera; it’s compact, radiometric, and packs a punch. But not every situation calls for radiometry. In those cases, the Teledyne FLIR Lepton FS is perfect.
Ron Justin, GroupGets’s founder, says that “the lower specs are more than worth it for users only needing an imager, as opposed to a radiometric sensor.”
This Lepton FS comes at a great price – the lowest cost per pixel of the entire Lepton family – and is great for a ton of uses. It has low power consumption and is easily integrated into boards with appropriate Lepton sockets, such as the PureThermal Mini Pro JST-SR, the PureThermal Breakout Board, the PureThermal Micro Breakout Board, and more. It has the thermal capability for many of your thermal monitoring products.
One customer, named "Willy" on the CNX Software website, gave the inspiration behind this article's focus:
"For many (non-professional) applications, you just want to distinguish “hot” vs “hotter” vs “cold” vs “colder”. You don’t really care about exact values. That’s enough to see hot air leak around a window or a door… How many users know how to calibrate their FLIR thermometer's emissivity settings to adjust it to the material being measured anyway? That’s why I think it’s great to propose “junky FLIR for the masses”, there definitely is some demand for this."
Brief Technical Specifications
- Sensor technology: Uncooled VOx microbolometer
- Spectral range: Longwave infrared, 8 μm to 14 μm
- Array format: 160 x 120, progressive scan
- Pixel size: 12 μm
- Effective frame rate: 8.7 Hz (commercial application exportable)
- Thermal sensitivity: <75mK NEdt
- Scene dynamic range:
- High Gain Mode: -10 to 140 degrees C typical
- Low Gain Mode: -10 to 350 degrees C typical
- Input clock: 25-MHz nominal, CMOS IO Voltage Levels
- Video data interface: Video over SPI
- Control port: CCI (I2C-like), CMOS IO Voltage Levels
- Package dimensions without socket (w x l x h): 11.50 x 12.70 x 6.835 mm
- Weight: 0.91 grams
- Optimum operating temperature range: -10C to +65C
- Non-operating temperature range: -40 C to +80 C
- Shock: 1500 G @ 0.4 ms
The FS in Day-to-Day Life
Some of our customers have reached out to tell us of the creative and innovative ways they utilize their FS. To better exemplify the many uses of the FLIR FS, I got my hands on one and went into the real world to try and replicate some of them. My set up is a tCam Portable Thermal Imaging Kit.
The tCam Portable thermal imaging kit includes a 3D printed enclosure, ESP32-based GUI visual board called the gCore and thermal imaging board, tCam-Mini
I put these on an SD card and downloaded the tCam View Console desktop app so that I could play around with the images. It allows you to connect to the camera and change the color scheme of your photos and videos. I’ve put some below with the heat palettes changed to give you an idea. I will say I had way too much fun picking the palettes I liked best for each photo.
A hand with very cold fingers holding the FLIR Lepton FS
1. Building heating losses - identifying badly insulated windows
Are you in sweatpants, a jacket, and wrapped in a heating blanket constantly? Me too - but the last one is by choice. It’s frustrating to think that the precious heat you pay for is seeping from the cracks and crevices of poorly insulated areas left by your builders. Don’t you want to find out where they are so you can fix them, once and for all, and relish the wonderful heat?
2. Electronics' heat dissipation
Your PC tower getting toasty after an intense gaming sesh? Are you worried about which components are under the most pressure? With the FS you can identify what area of your master build is giving off the most heat.
(From Left): Showing uneven heat dissipation from my laptop. (Right): The surge protector next to my PC tower - the PC was warm, but the protector was hot where they were in contact
3. Occupancy Monitoring
Smart buildings are integrating thermal cameras for occupancy measuring. They don’t need to know the temperature of someone’s body, or the temperature of the room. They want to see how many people are going in or out, and how many congregate in a room.
4. High altitude pictures for thermal landscape maps
One of our customers participated in a competition in Poland where they integrated a FLIR Lepton FS into a probe about the size of a soda can, which they launched in the air to take high altitude pictures of the landscape. Later the images were compiled to make a thermal map of the land. The FLIR FS can even be attached to our DroneThermal board, a micro size and low-cost analog thermal camera for small UAVs and surveillance.
The camera circuit is designed to work with 1S LiPo (3.5-4.2 volts). The absolute maximum supply voltage is 5.5 volts.
5. Measuring animal behavior and general temp data inside farms
More than a few of our customers have told us that they use their FLIR FS to monitor animal behavior in different situations, from inside their commercial farms, to their backyards. One customer uses it in their pest-control company to track pests and birds.
This adorable critter ran through our office like a fluffy little whirlwind. I was able to track her journey with my FS. I put my life on the line to get this photo – she’s still teething.
The vicious predator seen hunting the defenseless toy stashed under a desk.
6. Taking some rad photos
Maybe it’s because I’m new to thermal imaging, but I loved taking the tCam Kit around with me. I went to my favorite bar and got some great shots of my friendly neighborhood bartender, the other attendees, even the rafters (in my defense, I think they look cool).
The rafters of the bar. In real life, they are charred black from a fire that happened over two decades before. Here they remind me of a rib cage. Just me?
My favorite bartender and business owner.
A lovely couple on the guy's birthday. They were happy to pose for my amateur photography.
7. Automobile safety
This is an extraordinary, and potentially life-saving way to use thermal imaging technology. You can make your own version of this with a FLIR FS – with a little creative engineering you can mount it on the car (protect it from the weather) and display it inside. No radiometry required. That’s direct from our in-house electrical engineer – and no, he didn’t go into detail about what “creative engineering” would be required to make this work, but I’m sure you’ll be able to figure it out in no time.
Thermal imaging of a deer (courtesy of Teledyne FLIR)
So, What's the Catch of Using the FLIR Lepton FS?
As discussed above, the FLIR FS does not have radiometric capability. For some, this is a con, yes. For those who don’t require radiometry data, though, why pay extra for it?
I’ll let you in on a little secret –some FS modules do output radiometric values per pixel. It isn’t common, however, so I wouldn’t count on it unless you buy a large quantity, then you might luck out. On that note, because of this, the Lepton FS units are not guaranteed against any radiometric accuracy. It’s a “use at your own risk” sort of situation.
The other concession is that there can be up to 3% inoperable pixels (number of non-defective pixels shall be > 97%). This means that there can be adjacent clusters, rows, or columns that may contain defective pixels that are not factory corrected and unable to be corrected. This is not guaranteed but can happen.
Testing the Lepton FS's temperature accuracy
Our engineer sent me home with the big green and orange ExTech temperature meter. My goal was to measure the temperature of certain objects and test the FS’s accuracy.
My mimosa was nice and chilly from the fridge. The tCam, pointing it at the glass, registers it as 19.4°C, and the sensor inside the drink registered it at 17.9°C
After a few hours playing video games my laptop was getting a little hot to the touch. I was interested to see the uneven heat distribution. It seemed to be colder near the WASD keys, where my left hand had been resting. But my right hand was not near the corresponding area on the right of the laptop.
I wedged the sensor under my O key. The FS was surprisingly accurate. The temperature meter registered under my key as 37.5°C, and the FS registered it at 38.0°C at the time I took the photo.
All of these photos / experiments were taken with the same FS module.
So, FFS – just get an FS!