FLIR TG130 Low-End Thermal Camera Review

[Gyro]

I managed to pick up a FLIR TG130 for what I thought was a good price (£168) in the Amazon black friday sale. I've finally had permission from Santa and time to do a mini review. I haven't seen it for less anywhere since, but the RS and Farnell prices are better than the normal Amazon price even after you take VAT into account.

It was a bit of a risky buy. Obviously the TG130 is right at the bottom of FLIR's offerings, but given that I couldn't justify the significantly higher (ie. starting at double'ish) cost of their other offferings it seemed worth going for. I don't have a smartphone either (luddite!) which ruled out the FLIR One and Seek Thermal too - both more expensive anyway and a more cumbersome solution for close-in PCB work.  At least it was FLIR though and not one of the ebay no-brand 32x32 or 6x60 photoshopped specials.

Basic spec then: Point and shoot, integrated display (1.8"), 80x60 Lepton 2 (with shutter). Power button and trigger to freeze frame. Single point measurement. No storage or removable card. Fixed focus lens down to 100mm, FOV 55x43 degrees. AGC only, so the image colours track the coldest and hottest items in frame. Colour pallet: Iron only. [EDIT: Emissivity fixed at 0.95]. Batteries 2 x AAA alkaline (4 hours quoted). In a word, humble. The full user manual including mechanical drawing is here: http://flir.custhelp.com/app/account/fl_download_manuals

Actually, I had no problem with the above spec, I wanted something compact and self-contained. No particular interest in taking thermal photos (would have been helpful for a review though!). I basically wanted it for PCB and general fault-finding, single point measurement and freeze-frame is fine for that. 80x60 is low for these days, but at least it's a Lepton 2 with a track record which has been 'adequate' for several years. Worst case, I could pull it out, put it in an adapter board and still not loose money.

Initial impressions then... Not too shoddy. The AGC is very noticable when you start swinging it around the room and the background colours change. It would be nice to be able to lock the temperature range, but it becomes much less of a problem when you point it at a fixed scene. Pointed at an exterior wall (from inside) and I can see the outlines of the thermalite blocks under the plaster. As long as there is some thermal contrast in the scene then it's fine, otherwise the image gets noisy. It can clearly see thermal 'traces' on the carpet and furniture. Startup to image is fast, you can see the image freeze and hear the click of the shutter at intervals as it normalizes the sensor elements. The spot reading shows approximate (leading ~ ) for anything between 30secs and a couple of minutes while it self calibrates. Display size seems adequate for the resolution - and keeping everything compact, the slimmer the profile, the easier to see what you're pointing at. Temperature measurement tops out at 150'C, enough for semiconductors but probably not some wirewound power resistors (though it can still image them of course).

Turning to PCBs, I was expecting the fairly wide FOV to be a problem but in practice I found that the imager is useable a lot closer than the 100mm min. The first image shows a 0.1" through-plated matrix board held in the palm of my hand at 10mm distance. Ok, at 80x60 resolution 'focus' is a bit academic, but the image is pretty clear, certainly enough to be able to be able to check 0603 parts. I really wasn't expecting that. The imager window is nicely recessed so would be difficult to scratch, even with sticking up headers. At very close distances some pincushion becomes evident. NOTE: There seems to be some beating effect between the LCD screen and [EDIT: the my] camera - the moire pattern is an artifact (you can see it's absent fron the second image).

The second and third shots show an Arduino Leonardo clone, being powered from a mains adaptor (voltage a bit high). The first, of the board at 100mm, and the second, of the AVR chip at approx 10-15mm.

Turning to the power source (last photo). The three AAA batteries are mounted in a 'Lithium replacement' battery holder. This is probably a bonus against worrying about aging of an internally fitted cell. I measured the supply current at approx. 150mA. The low battery icon and shutdown happen between 3.2 and 3.1V. Not quite low enough to get full capacity from alkaline cells but ties in pretty well with the 4 hours stated life. Backlight brightness changes with supply voltage. Clearly the thresholds also match a Lithium cell. The holder length is about 55mm. Too small to replace with an 18650 cell, but a 18500 cell would go - the unprotected 'Vaping' cells are 50mm, but there are protected versions come in at about 54mm. 1500mAh should give about 10 hours life. Might be worthy of experementation, but running cost should be pretty low anyway. NiMH would be another option of course.

On Fraser's advice, I purchased a 20mm ZnSe lens (76mm I think) I have still to experment with using it to narrow the FOV, I'll report back when I've found a neat way to mount that - the case doesn't have many straight edges and I don't want to resort to tape. I'm sure there are mounting screws behind the display window, but I'm not going to be persuaded to do a teardown! There's probably little to be gained anyway - it's pretty unlikely that there's going to be a card socket footprint in there, or anything to drive it. The Lepton is bound to be socketed.

Conclusion: A significant and reasonably economical addition to my fault finding aids, your mileage may vary!

[Gyro]

An update on battery life, if anyone's interested. Half used supplied alkalines are showing dips in backlight brightness when the FFC shutter activates, occasionally blinking the low battery icon. The cell internal resistances are obviously too high. 950mAh NiMh cells on order - looking at the discharge curves and end-point voltages, they will last significantly longer in practice.

[Gyro]

Some quick experimentation with the 76mm ZnSe lens. As would probably be expected, it usefully narrows the field of view, allowing a bit more spacing from the target and higher magnification close in. Loss of focus close up doesn't appear to be an issue.

First image: lens (20mm dia) + masking tape ( )
Second image: TO220 LM317+single resistor current source (for the NiMh batteries, proving useful already)
Third image: SOT223 on the Arduino clone, on decent amount of copper pour.

Edit: Better Images... Capturing decent screenshots with two hands really is a pain, thankfully only needed for this sort of post.

[Gyro]

A quick update on battery types.

I've been running with 950mAh AAA NiMh cells for a couple of weeks now, still on the original charge with no sign of fading. It's hard to judge how many hours but considering the original Alkaline cells started failing after a couple of days it's a big improvement. These should be considered essential for the TG130, there's no longer any sceen dimming at all when the FFC shutter actuates and the image clean-up and temperature calibration at startup are faster too. FLIR's claim of 4 hours use on Alkaline cells seems very optimistic.

There doesn't seem any point in further investigating trying to bodge in a 18500 Lithium cell now, NiMh is easier and more cost effective.

[Spirit532]

there's no sceen dimming at all when the FFC shutter actuates

The Lepton has a featherweight shutter, I believe it pulls under 10mA when driven hard.

[Gyro]

That's what I would have expected too but looking at the Lepton 2 datasheet, the VDDIO supply current goes from 2mA typ (4mA max), for the shutterless version, right up to 235mA typ (310mA max) for the shuttered version during FFC!  The minimum permissible VDDIO voltage also increases from 2.5V to 2.8V when shuttered (3.1V max on both).

That puts the FFC shutter disipation at 700mW assuming a VDDIO of 3V. Not as featherweight as you might think! Maybe there's something else that happens at the same time but it's the Lepton's I/O ring supply. Non of the other rails specify any difference during FFC. Any alternative interpretations?


Edit: http://www.flir.com/uploadedFiles/OEM/Products/LWIR-Cameras/Lepton/Lepton%20Engineering%20Datasheet%20-%20without%20Radiometry.pdf

[Bill W]

Could also be processor intensive during FFC ?

Will try measuring a shutter drive as I have one out

Bill

[Bill W]

The solenoid on the Flir One shutter is 12 ohms.  That is close enough to the 235mA if given 2.8V.

It should also be noted that it requires current to hold closed for the whole FFC time, it is not a bistable solenoid as some are on higher level cameras.
Bistable solenoid or a stepper motor allows both a 'close when off' function and just two short pulses (perhaps only 50ms) to switch state.

Bill

[Gyro]

Thanks for the confirmation Bill.

It does seem like an awful lot of current to hold one tiny shutter closed, doesn't it. I suppose the TG130 is the only one to suffer because it's the only FLIR offering to run on alkaline cells rather than embedded Lithium ones.  Thankfully NiMh does solve the problem.

I'm surprised it hasn't been flagged as an issue by people using Leptons in breakout boards (from my search anyway), it's quite a power overhead compared to the normal operating current, even if it is short duration. Having seen what happens to the image when the supply drops out of regulation during the FFC cycle, it's not a pretty sight!

Chris

[Gyro]

Damn...

https://www.ebay.co.uk/itm/FLIR-TG130-Spot-Thermal-Camera-Black-SEE-PICS-/253421507631?epid=2255980065&hash=item3b0119542f%3Ag%3ATpwAAOSwmuVagDBI&nma=true&si=JNtOO2sAnC5H1WYzIFmL%252BCSxNAs%253D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557

I'd had my eye on that one. I was hoping that would be cheap enough to do a teardown on! It would be interesting to know what was causing it to hang like that - especially on a model with removable battery. No way I would risk that much on a non-working one without an external interface though.


P.S. NiMh cells still on their initial charge. 

[Fraser]

Gyro, agreed. £90 is a lot to pay for a unit that can be purchased working for not a lot more !

EBay can be a crazy place but 20 bids shows you that some people were intent on owning it. Did not tempt me at all. Maybe the new owner is a member here or will discover this forum whilst researching information on it. Sadly if it is a firmware problem it is likely a RTB repair.

I am going to sell some of the customer returns F1G2 camera dongles on eBay as they seem to achieve decent money there. I suspect people have realised that it is a cheap route to Lepton3 ownership 

Fraser

[Gyro]

Yes, ebay is a strange place. Once that one topped £30 I lost interest (I didn't bid).  The 'new' TG130 UK listings currently span £202 to £571 . Most are higher than Amazon and [EDIT: Farnell RS and CPC]

Now if I had even the slightest hope that I could just plug in a Lepton 3, then I'd have the screws out in a flash and would be biting your hand off for an F1G2 return!

Chris