As much as we like to give Kickstarter campaigns a hard time (or just outright laugh at them), we've seen some cool ideas come to fruition thanks to crowd-funding. Among those, Thermodo is an interesting little gadget: it's essentially a small thermometer that plugs into a phone's or tablet's headphone jack and interacts with the device through an app to give the temperature of the current location. I'm not entirely convinced of its practical usage, but the idea is definitely neat. And let's be honest here - nearly everyone has some sort of weird fascination with the temperature (or the weather in general). I definitely do.

I've had both the the "regular" ($30) and premium ($45) Thermodos for the last few weeks and tested them on various devices, including the Nexus 5, Nexus 7, and *cough* iPad Mini. While I initially expected the experience to be pretty straight-forward (plug it in, launch the app, get the temp), that's actually not the case. There's a slight learning curve to using Thermodo, and it takes a bit of tweaking to get what's assumed to be an accurate reading.



  • Small, lightweight, fits on a keychain
  • Convenient...if you're in the market for a thermometer that connects to your smartphone
  • Varying results depending on device (until properly "calibrated")
  • Can take some time (and trial/error) to get the settings dialed in perfectly
  • Kind of pricey for what it is
  • Very limited uses
  • No dedicated tablet UI for Android

Aesthetically, Thermodo is a little-bitty thing with a very simple design. It's basically just a plug with slightly large end, which is naturally where the unit's internals are found. It weighs only seven grams and comes it at almost an inch and a half in length (including the protective "sleeve"), so it's easy to throw on a key ring without really getting in the way.

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The "regular" version of Thermodo comes in either black or white, and features a machined aluminum body with a scratch-resistant coating and hand stamped logo; the premium model has an anodized surface and engraved logo. That's literally the only difference between the two - they both function the same way. It's all about getting the one that looks best to you...though the premium edition is $15 more than its "basic" counterpart. For the same thing. Not really sure it's worth the extra dough.

When it comes to functionality, it's really kind of hit and miss depending on the device you're using. There are several different variables to consider, with ambient heat being the most prevalent. Since each device is different internally (even down to the headphone jack itself), you can pretty much guarantee that each one is going to spit out a different reading. As I stated in the intro, I used primarily three different devices for this review (and even tried it out on a few others), and every single one of them provided a different result with the stock settings. That's frustrating.

Fortunately, there are certain things you can do to ensure the most accurate reading for your device. During what I'd consider to be a calibration process, it's best to be in a room where the temperature is controlled and you can check the reading. For example, my house is kept around 72, but I did most of my testing in my home office, which is always hotter than the rest of the house because of the lights, computers, monitors, and TV that are essentially always on. I imagine it's closer to 74 or 75 in here, which is what I went with when trying to get the spot-on temp with Thermodo. It's also worth noting that I used the same process for all of my testing devices.

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Firstly, I just popped the Thermodo in and let it do its thing. It takes several minutes for it to produce a steady readout, so leaving it alone for a few minutes (I'd say two to five) is the best option initially. This gave me a good idea of how high the reading was going to be. After that, I grabbed an audio extension cable and plugged Thermodo into it. This essentially negated the device's ambient heat to provide a more accurate reading. Sure enough, after just a few minutes the difference was pretty drastic - easily upwards of five degrees. With the extension cable, it settled at around 75.4, which I feel like is probably pretty accurate where I'm sitting.

After that, I removed the extension cable and put Thermodo back into the port by itself. In the app's settings there's an option to compensate for device heat, which offers a couple of generic options (regular and warm), along with a custom setting. I gave the unit a few minutes to adjust, then started tweaking till I got a similar result to what it showed when using the extension cable. Turns out for the Nexus 5 the difference is about 11 degrees Fahrenheit. For the Nexus 7, it's about 6.5. The iPad Mini reads at about a two degree difference. It really all depends on the device.

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Of course, that's not a foolproof system: it's possible that the sun will heat up a black device quickly, thus raising the ambient heat by a few more degrees. I didn't actually get that effect when I tested it here, but it hasn't been "Texas hot" yet, which I feel like would be required before affecting the readout post-calibration. Honestly, though, I think the most accurate reading is always provided with an extension cable and no heat compensation within the app. If you want to use Thermodo for precise temperature readings, that's the only way to go. For quick and dirty readings, just shoving it into the headphone jack will do the job.

It's also worth nothing that Thermodo won't read anything when the display is off. This leads to two things: increased device heat and a reduction in battery life. Not only does the display start to eat up more battery, but the Thermodo app itself munches away at the CPU, as well. Here's a screenshot from testing this morning:

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The app itself is incredibly simple: it shows the current temp, along with some subtle indicators that show whether it's rising or falling. Very, very simplistic. The settings menu is equally as simple, with just the must-have options: Celsius/Fahrenheit toggle, heat compensation, and the option to show the indicator arrows for which way the temperature is going. Bare-bones. The "about" menu has some good advice on getting the most out of Thermodo, which comes in handy when figuring out how to use it.

Unfortunately, the Thermodo guys also chose to offer one app for Android tablets and phones instead of a scalable interface depending on the type of device. The iPad app's interface is much better than that of Android tablets like the N7 – it shows all the info, including settings, on one screen. There's so little to the application, this is easily the most effective way of laying it out on a larger screen, and I would really have liked to see the same interface on the Android tablet app. The iOS app also has some nice little animations and additional features not found on Android, like a low/average/high readout. It's beyond obvious that more time was spent on the iOS app than Android, and the latter was just thrown together to get something out the door. Not cool, guys. Not cool at all. Thankfully, that can be remedied in an update.

Photo May 06, 12 49 20 PM

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Overall, I think Thermodo is a fun little novelty accessory. It probably won't have any "important" real-world use, but it's a neat little thing to plug into your phone and get a quick temp readout for...whatever reason. Whether or not it's worth $30-45, however, is another story altogether. If you have some funds to throw away on something you'll probably only use for a like a week then never think of again, then by all means, pick one up. Otherwise, I'm not sure I would say it's worth the purchase without a good reason...which probably doesn't actually exist. So, just buy one if you want it.

Buy: Thermodo

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Cameron Summerson
Cameron is a self-made geek, Android enthusiast, horror movie fanatic, musician, and cyclist. When he's not pounding keys here at AP, you can find him spending time with his wife and kids, plucking away on the 6-string, spinning on the streets, or watching The Texas Chainsaw Massacre on repeat.

  • Steve Freeman

    So what you're saying is, it's not accurate. And a thermometer that's not accurate has about as much use as a car without wheels.

    • http://www.androidpolice.com/ Cameron Summerson

      No, I'm saying it takes some work before it's accurate. I think that, after proper setup, it's fine.

      • Steve Freeman

        I disagree...according to your own article, you get the best results using a 3rd party extension cable. So the device, on its own, when plugged directly into your phone or tablet as intended, even with compensation enabled, isn't entirely accurate. Unless if you spend the time to create a custom compensation setting to match the extension cable results, though as we all know the heat of a device can fluctuate depending on what it's doing at the time. So any custom compensation setting you create would only be accurate in certain situations. Therefore, unless if I'm missing something, it's not very accurate.

        • http://www.androidpolice.com/ Cameron Summerson

          Thermodo's website encourages the use of extension cables, so it's still being used "as intended."

          • Steve Freeman

            Well hell, since they know it's an issue, for the price they're charging it should come with an extension cable.

      • Mike Reid

        For the price, I think it should be calibrated by the manufacturer, internal to the device.

      • blahmoomoo

        I dunno, something tells me they could have done SOMETHING to better thermally isolate the headphone jack from the sensor in the device. You couldn't make it perfect, of course, but reading 11 degrees higher because of the device it's plugged into sounds inexcusable to me. And even if it usually reads 11 degrees higher, the heat coming from the device itself varies depending on your usage.

        Requiring an extension cable seems like too much of a bother to fix this flaw.

        • Chris Vander Maas

          It's not thermally isolated in anyway, shape or form by the sounds of it. Aluminum body over a low thermally conductive body, huh? Form over function! That $30 is all profit, cheap sensor, cheap design, cheap app! I can see them defending this toy by pulling a line from Steve Jobs "It's not the device, your holding it wrong" Can we have a teardown of one of them to find out what sensor it's packing? I'm willing to bet it's a cheapo Dallas One Wire sensor, they would be easy to power and signal over the headphone jack, I'm thinking I could make one of these in about 15min, and that's including a simple app.

  • supremekizzle

    Just become friends with a Minnesotan. It seems like anyone you talk to always knows the 10 forecast including highs and lows. Oh, and how much we hate the winter and the cold, bitching about it year after year, yet never moving away... Hell.... I'm still here...

    • Steve Freeman

      I'm in Cleveland, fairly close to the lake (at least close enough to get lake effect weather), and it's the same thing here. Always bitching about how much snow we get, and how cold it gets, and then how humid it is in the summer, yet we still live here. I think it's because we're dumb.

  • Dazrin

    Is it water proof? Meaning can at least the top part be submerged? If it can, an easy way to calibrate would be to let it sit in some ice water for a while. Make sure the ice water is well-stirred and lots of ice. It should read 0 C or 32°F in ice water.

  • Jephri

    That looks hot. Or cool. We'll go with hot

  • Josh Shaw

    Why would you need to replace the one already in your Note 3/S4/S5?

  • Jephri

    I would like to see one of these for taking a person's temperature.

    • Roger Siegenthaler

      Exactly what I was thinking, the one "practical" use for this I can think of :).

  • BruinGuy

    I bought one when it was on Kickstarter. I used it a couple of times. Tried to calibrate it but could never seem to be anywhere near close to accurate. So, it just sits in a drawer.

  • Chris Vander Maas

    What's the precision of this thermometer? Clearly, it's not accurate for anything other than comparisons to previous readings using the same device, but does it have the precision to even make that useful? A tenth of a degree isn't exactly the most precise; and for the cost of this device, an SHT25 sensor could be used to get very accurate and precise temperature AND humidity readings, with a few bucks to spare! Heck, for $30 you can get a cheap laser temp sensor and not have to muck about moving extension cables to heat balance your computer case.

  • tdurden64111

    Can these be used as a rectal thermometer? Asking for a friend.

  • Eric Jones

    I think most people would have more fun spending half the price on an infrared thermometer, which is more accurate and can measure the temperature of many things without touching them. If you want to know the specific temperature of the room you are in, just buy a cheap thermometer. I spent ~$20 and bought an atomic desk clock with a thermometer in it. The thermodo is gimmicky, inaccurate, and overpriced.

  • Rob C

    I'd put that money towards better earphones and rely on the "Weather App" on my Home Screen.

    While the Weather App does not show the exact temperature of the room I am in it does show a prediction of the temperature (and Weather) in the hours/days to come (and not just where I am but World-Wide if I change my selection).

    It has lower accuracy (even than this thing), bigger range (even than an infrared thermometer that Eric suggested) and more features (Weather too) plus it has an Animation that is not cheesy or cheap that characterises the Weather (EG: "Sunny" shows the Sun, "Cloudy" shows clouds, "Windy" has clouds move with 'wind sounds' and Lightning or Rain are just plain realistic, to the extend that it is possible)