Paul Ockenden gets ex­cited about an up­date to Flir’s low-end ther­mal im­ager, and looks for the magic in fast phone charg­ing

PC Pro - - November 2017 Issue 277 -

Quick-charg­ing phones aren’t magic, you might be dis­ap­pointed to dis­cover, but a sim­ple demon­stra­tion of physics. Plus, a ther­mal im­ager gets Paul hot with ex­cite­ment.

If you’ve ever seen a pic­ture from a ther­mal imag­ing camera, it’s very likely to have come from a Flir model. Al­though there are a few other players in the mar­ket, Flir seems to be spec­tac­u­larly dom­i­nant. The com­pany is nearly 40 years old, and orig­i­nally set up to pro­vide ther­mal imag­ing for air­craft – the kind of things you see when­ever the mil­i­tary boasts about a pre­ci­sion mis­sile hit dur­ing times of con­flict. The Flir name comes from “for­ward-look­ing in­frared” – the type of camera that’s mounted on a plane.

Air­borne cam­eras are just a small part of the ther­mal imag­ing mar­ket th­ese days. There are also many hand­held cam­eras, such as those used by emer­gency and res­cue ser­vices (for check­ing fires, or look­ing for life­signs af­ter an earth­quake), and also for such tasks as en­vi­ron­men­tal sur­veys of build­ings, for ex­am­ple.

Un­til a few years ago, such cam­eras cost many thou­sands of pounds. But in late 2013, Flir dis­rupted the very mar­ket in which it was so dom­i­nant. It re­leased a camera known as the Flir One for just over £300. Rather than be­ing a stand­alone de­vice, it was an at­tach­ment for an iPhone, so was able to use the hand­set’s screen and processor.

The biggest prob­lem with the Flir One was its form fac­tor: it only worked with the iPhone 5 and 5S, which limited both the ap­peal and the longevity of the prod­uct. Ap­ple isn’t known for keep­ing its iPhone mod­els go­ing for long, and I reckon Flir was re­mark­ably lucky in this re­spect, with the iPhone SE (which is based on the iPhone 5) still be­ing avail­able four years later.

This re­stric­tion was over­come in late 2015, when Flir re­leased a new-gen­er­a­tion camera that was avail­able for both iOS and An­droid phones (and tablets – peo­ple of­ten over­look how well th­ese gad­gets work when plugged into a big­ger screen). It was quite un­like the orig­i­nal Flir One from a couple of years back – but, con­fus­ingly, the com­pany still kept the same name. I wrote about it here al­most ex­actly a year ago ( see is­sue 265, p113).

Now there’s a new, third­gen­er­a­tion de­vice that’s just been re­leased here in the UK, which I’ve been test­ing for a few months. You won’t be sur­prised to learn that de­spite it be­ing a com­pletely dif­fer­ent de­vice once again, the com­pany is still call­ing it the Flir One. If noth­ing else, you have to ad­mire its con­sis­tency!

Ac­tu­ally, there’s plenty more to ad­mire. The new ver­sion com­prises a stan­dard and a Pro model. On­line you’ll see en­thu­si­asts re­fer­ring to the new mod­els as F1G3S and F1G3P; the pre­vi­ous two be­ing F1G1 and F1G2.

The stan­dard F1G3S model is ac­tu­ally a step back from the pre­vi­ous F1G2 model, since it has a low­er­res­o­lu­tion sen­sor (80 x 60 pix­els ver­sus 160 x 120), but that’s re­flected in its price: at £216 di­rect from Flir, it’s likely to drop to just be­low £200 once it be­comes wide­spread in the dis­tri­bu­tion chan­nel. The F1G2 typ­i­cally sold for around £300, so that’s quite a sig­nif­i­cant drop.

How­ever, the more in­ter­est­ing de­vice for me is the new Pro model. It has an RRP of £400 – al­though, again, I ex­pect it will be avail­able for less once it be­comes more widely avail­able.

The Pro has the same 120 x 160-pixel in­frared sen­sor as the

pre­vi­ous ver­sion, but the vis­i­ble spec­trum camera that it pairs with has an in­creased res­o­lu­tion – up from VGA (640 x 480) to 1,440 x 1,080. As with the pre­vi­ous two gen­er­a­tions, the ther­mal and op­ti­cal im­ages are blended to­gether to cre­ate a de­tailed im­age.

It’s ad­di­tional pro­cess­ing, rather than this in­creased op­ti­cal res­o­lu­tion, that re­sults in the F1G3P of­fer­ing sig­nif­i­cantly bet­ter im­age qual­ity than the F1G2. Flir calls this tech VividIR, and the re­sults are as­ton­ish­ing. You can pick out de­tails us­ing the new model that the sec­ond gen­er­a­tion will com­pletely miss. I just did a test, in which I walked across a floor bare foot. A minute later, the F1G3P can still dis­cern my foot­prints on the floor where the F1G2 couldn’t see any­thing.

A new app ac­com­pa­nies the new hard­ware (note that it also works with the older mod­els). Some as­pects of this soft­ware haven’t gone down well with ex­ist­ing users – in par­tic­u­lar, the ini­tial re­quire­ment of manda­tory reg­is­tra­tion be­fore the camera will al­low you to take any pic­tures. Plenty of other soft­ware does this too, but due to the re­sponse Flir has since re­moved the need for such de­tails.

The new app also fea­tures so­cial feeds and a selfie mode, nei­ther of which make me ex­cited. It isn’t pos­si­ble to dis­able them ei­ther, but you can ig­nore them.

One thing I do like is that it will pair with a smart­watch. So if you need to fig­ure out what’s go­ing on in an awk­ward space – in an en­gine com­part­ment, per­haps, or be­hind a fridge – you can push your phone into the gap with one hand and see the ther­mal im­age dis­played on your watch face. En­sure watch and phone aren’t at the end of the same limb, though!

The hard­ware it­self isn’t too dis­sim­i­lar from the pre­vi­ous ver­sion, but there are a couple of neat touches. First, the An­droid ver­sion uses USB-C rather than mi­cro-USB; Flir will have a so­lu­tion for those with the old­er­style socket in a few months. But USB-C tack­les the prob­lem with the pre­vi­ous ver­sion, where the camera some­times needed to be re­versed de­pend­ing on which way round the socket was on your phone.

Sec­ond, there’s a neat fea­ture where the protrud­ing USB-C plug (or Light­ning for iOS) can be wound in and out, so you don’t need to re­move your phone from its case to plug it in. This is es­pe­cially handy for those work­ing on build­ing sites and sim­i­lar, who keep their phones in thick, rugged pro­tec­tors.

Over­all, I’m re­ally im­pressed with the new Flir One Pro.

Who’s in charge?

There’s a lot of mis­in­for­ma­tion and mis­un­der­stand­ing out there when it comes to mo­bile phone charg­ers. For ex­am­ple, the other day I over­heard a shop as­sis­tant telling a cus­tomer that a par­tic­u­lar USB charger wasn’t suit­able for her phone be­cause it “chucks out too much amps”. I sus­pect my real-life LOL – hon­estly, I couldn’t help it – made it rather too ob­vi­ous that I knew the sales­man was talk­ing ut­ter non­sense.

When it comes to charg­ers, you’ll see three fig­ures men­tioned: the volt­age (V or volts), the cur­rent (A or mA for am­peres; usu­ally short­ened to amps and mil­liamps), and the power (W or watts; named af­ter the steam en­gine bloke). The power is sim­ply the volt­age mul­ti­plied by the cur­rent, so 5V at 2A is 10W. And th­ese days you’ll find it’s the power that’s used to dis­tin­guish dif­fer­ent charg­ers. So will a 20W charger top up your phone twice as fast as a 10W model? Pos­si­bly yes, but prob­a­bly not. To dis­cover why, we need to think a lit­tle more about cur­rent and volt­age.

Some peo­ple will tell you to think of it like a river: the volt­age be­ing how fast the river is flow­ing, and the amps are how wide and deep the river is. Mul­ti­ply them to­gether to get the power; the amount of wa­ter pass­ing through. Ex­cept that’s prob­a­bly the worst anal­ogy you’re ever likely to hear. I’m not even sure there’s a good anal­ogy - I re­mem­ber my old O-level physics teacher telling me to think of volt­age as if it was height, or al­ti­tude, and cur­rent as if it was weight. But that just re­in­forces the shop as­sis­tant’s as­ser­tion that too many amps would da­m­age a phone.

My ad­vice is to for­get all th­ese analo­gies! Just re­mem­ber that the pri­mary con­sid­er­a­tion with a phone (or, in­deed, any other charger or power sup­ply) is that it de­liv­ers the cor­rect volt­age. Any lower and the de­vice won’t charge; any higher and the de­vice will be dam­aged – pos­si­bly with some flames and smoke in­volved! There may be a small de­gree of tol­er­ance, but in gen­eral, the charger volt­age needs to be what the de­vice is de­signed to ac­cept.

Then we come to the cur­rent. A phone with a drained bat­tery will have a max­i­mum cur­rent it can draw from a charger. Let’s take an ex­am­ple of a phone that’s look­ing for 5 volts at 1 amp. If the charger is rated for 5V and 2A, this re­ally doesn’t mat­ter (pro­vided it’s a de­cent-qual­ity mod­ern charger) – the phone will sim­ply draw 1A of the avail­able 2A.

So think of the rated volt­age of the charger as a fixed value, and the cur­rent as a max­i­mum – this is re­ally what the sales­per­son in the shop should have known. The volt­age has to be right, and the cur­rent out­put should ide­ally match what the phone needs, but if there’s more avail­able then it won’t hurt (or be used).

But what hap­pens with an un­der-rated charger? What if our phone wants 5V at 1A but our charger is only rated for 5V at 500mA (or 0.5A)? Well, to a large ex­tent this de­pends on the charger. Cheap, old or poor-qual­ity charg­ers might over­heat as they strug­gle to de­liver the cur­rent be­ing de­manded, but the vast ma­jor­ity of charg­ers on the mar­ket to­day will sim­ply limit their

“The pri­mary con­sid­er­a­tion with a phone charger is that it de­liv­ers the cor­rect volt­age”

cur­rent and your phone will charge at a slower rate.

For safety rea­sons, and also to max­imise the life of your bat­tery, your phone will prob­a­bly vary the cur­rent it draws through­out the charg­ing cy­cle. When the bat­tery is empty, it will fill up rapidly – but, typ­i­cally, when half-full the charg­ing cur­rent will be re­duced, fall­ing fur­ther as the bat­tery reaches full ca­pac­ity.

This is best prac­tice, but the way some phones try to achieve a faster charge time is by up­ping the point at which the charg­ing cur­rent starts to ramp down. 60% and 70% aren’t un­com­mon, and some phones are push­ing to­wards 80% be­fore the charg­ing cur­rent re­duces. I do worry about the longevity of the bat­ter­ies in th­ese phones.

How­ever, a prob­lem is that with greater cur­rent comes greater heat­ing in the wire that con­nects your charger to your phone, and in the con­nec­tors, in­ter­nal wiring, and so on. This heat­ing ef­fect doesn’t de­pend on the volt­age – only the cur­rent. It’s why fuses – which are de­signed to melt a thin wire when it gets hot – are rated in amps rather than watts; a fuse doesn’t care what volt­age it’s work­ing at. So the greater the cur­rent, the faster the phone charges, but also the more heat is gen­er­ated. There is a way round this prob­lem, how­ever, which I’ll come onto in a bit.

Of course, peo­ple want their phones to charge as quickly as pos­si­ble, and so over time, there have been many schemes de­vised to achieve this. Some (no­tably Ap­ple) just get on with it, while oth­ers have fancy names such as Qual­comm’s Quick Charge, OnePlus’ Dash Charge, Oppo’s VOOC, Sam­sung’s Fast Adap­tive Charge, Huawei’s Su­perCharge, or Power De­liv­ery as part of the USB-C stan­dard. But none of th­ese is magic – charg­ing is all about get­ting power into a bat­tery, and as I men­tioned above, power is sim­ply volt­age mul­ti­plied by cur­rent. It’s ba­sic physics. Th­ese fast-charg­ing schemes sim­ply al­low greater charg­ing power.

To avoid heat­ing ca­bles and con­nec­tors, some of th­ese sys­tems de­liver a higher volt­age (and so re­duced cur­rent, for a given power level), with the volt­age then be­ing re­duced to what’s needed within the phone it­self. It’s a bit like how the Na­tional Grid works – high volt­ages (with low losses) for long ca­ble runs, re­duced down to us­able volt­ages lo­cally.

In phones, this volt­age re­duc­tion is of­ten pro­vided as part of the SoC (Sys­tem on a Chip) at the heart of the phone. Take Quick Charge, for ex­am­ple. The orig­i­nal ver­sion was sup­ported by the Snap­dragon 600 SoC – that was just 5V at 2A (so 10W). The 800 series along with the 610 and oth­ers brought Quick Charge 2, which added 9V at 2A and 12V at 1.67A (18W). Quick Charge 3 re­mained at 18W, but brought in a dy­namic volt­age abil­ity, al­low­ing it to vary any­where be­tween 3.6V and 20V – it was sup­ported by the Snap­dragon 620 and 820 pro­ces­sors, among oth­ers. The lat­est Snap­dragon 835 sup­ports Quick Charge 4, but there’s lit­tle reli­able de­tail avail­able about that, be­cause de­spite many phones us­ing this processor, most limit their charg­ing to lower stan­dards.

The Sam­sung Galaxy S8/S8+, for ex­am­ple, em­ploys a Snap­dragon 835 (or Sam­sung’s own, closely re­lated Exynos 8895 SoC), and uses Sam­sung Fast Adap­tive Charge, which is based on Quick Charge 2. Fol­low­ing the Note 7 fi­asco, many manufacturers – Sam­sung, in par­tic­u­lar – are be­ing su­per-cau­tious when it comes to bat­tery charg­ing; and rightly so. Many other 835-pow­ered phones also es­chew the lat­est ver­sion of Quick Charge.

One un­wanted side ef­fect of up­ping the volt­age to re­duce the cur­rent is that the phone be­comes warmer be­cause it then needs to re­duce the volt­age back down again. It’s why Quick Charge-equipped phones will of­ten drop back to a slower charge if you’re us­ing the phone at the same time as charg­ing it.

To avoid this, OnePlus and its par­ent com­pany Oppo use heftier wires and send 4A down a fat­ter than nor­mal charg­ing ca­ble. It also beefs up the con­tacts in the spe­cial USB plugs to avoid heat­ing is­sues there, too. It seems to work well – a fast-charg­ing OnePlus phone stays no­tice­ably cooler than many other flag­ship de­vices. And the phone con­tin­ues to fast charge even if you’re check­ing your emails or play­ing a game.

If you’re in­ter­ested in look­ing at the charge go­ing into your phone, I rec­om­mend a USB Power Me­ter. Plug it in be­tween your charger and the lead that goes to your phone. I’ve tested a few of th­ese over the years. The one I’d cur­rently rec­om­mend is the Muker-J7, which costs £10 from Ama­zon (

You can plug it in ei­ther way round, so you’ll al­ways be able to see the dis­play. It also has built-in mem­ory, so if you ac­ci­den­tally pull the power while mea­sur­ing the ca­pac­ity of an ex­ter­nal bat­tery pack, say, it will re­sume prop­erly when the power is re-ap­plied. Strangely, it says “USB Se­cu­rity Tester” on the case – I’ve no idea why!

It’s only once you start to look at the num­bers on a de­vice such as this that you re­alise that there’s no spe­cial magic to fast charg­ing a phone. It’s all about de­liv­er­ing power – watts – to the bat­tery as quickly but safely as pos­si­ble.

“The greater the cur­rent, the faster the phone charges, but also the more heat is gen­er­ated”


Paul owns an agency that helps busi­nesses ex­ploit the web, from sales to mar­ket­ing and ev­ery­thing in be­tween

BE­LOW I’d been sit­ting on this sofa with an iPad be­side me. Five min­utes later, the tell-tale heat sig­na­tures can still be seen

BE­LOW The Dash Charge sys­tem from OnePlus sticks to 5V, but uses up-rated ca­bles and con­nec­tors to de­liver higher cur­rent

ABOVE The new Flir One fea­tures a con­nec­tor that you can wind out to avoid hav­ing to re­move thick phone cases

ABOVE It says “Se­cu­rity Tester” on the case, but it’s re­ally an in-line mul­ti­me­ter

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