Three Points of the Compass likes to have an idea of the temperature on trail. Just how hot was that sweltering climb up? How much did it dip below zero in the small hours? Most little thermometers are pretty useless. Difficult to read, wildly inaccurate, easily broken, stupidly expensive or cheap and nasty. I may have found the answer…

Released on to the market in later 2019, the Oria SensorBlue Keychain Thermometer Hygrometer, model WS07, is a little 5.0 Bluetooth device for detecting temperature and humidity. In 2023, it cost me £10.19 off Amazon. I am not expecting this item to prove particularly robust but for that price I can take a punt and may be pleasantly surprised.

I had to download a Sensor Blue (ThermoPlus) app to my phone and this provides far more functionality than I actually require. I am not going to delve into the minutiae here but there is plenty there to keep the geeks occupied. Temperatures can be calibrated via the app and trends recorded then exported as a CSV document. Handily, the app will record data for up to 100 days but must be connected to the device at least once a day for this to happen. The Chinese made instrument has been altered since first released. Originally powered by a CR2032 battery, this has changed to a huge CR2477 battery, which has considerably lengthened life. While the advertised life of these is now ten to twelve months (up from the original 100 days), some users report that accuracy is lost after just one month so I’ll probably change the battery prior to each longer hike. The app does have a battery life indicator and signal strength.

It is a conveniently small and light product with a diameter of 36mm and 15mm depth. The outer case is made of ABS (Acrylonitrile Butadiene Styrene) which keeps the weight down to 20.7g, of which the battery alone weighs 10.2g. There is a short ‘leather’ hanging loop protruding from the side so it can be fastened to a pack with a mini ‘biner. If this wears out, it has two holes punched through it passed over an internal plastic tube so can easily be swapped out for some other material.

While many smart watches may be able to tell the temperature, wearing a watch on the wrist provides an inaccurate reading due to body heat being detected. Hanging on the pack, away from both direct sun and the body, is a better position during the day however I am normally more interested in temperatures at camp. Weather proofing for this little gauge is extremely limited, as it has openings through which temperature and humidity are sensed, and the whole white case simply snaps together.

The MEMS sensor constantly refreshes and has a purported range and accuracy of -20°C to 65°C (-4°F to 150°F) ±0.5°C (±1°F), and 0-100％ ±5% for relative humidity. While the range is ‘up to 50 metres’ in unobstructed areas, all I require is from my phone to the instrument hanging from my pack, or in the vestibule of my shelter.

While I am only interested in this gauge as a luxury item for backpacking, most users will be purchasing multiples, to keep one in each room, in the garden, the fridge, the greenhouse, the car…

There are both advantages and disadvantages to such a simple design. With a screenless design, it is cheaper, there is less to go wrong and data can be accessed remotely. Conversely, this is no ‘quick-glance and know immediately the temperature’, a phone has to be involved.

Three Points of the Compass first came across this thermometer via Robert Hammenrudh’s YouTube channel, so thanks to him for pointing it out. I’ll be using this little thermometer in 2023 and look forward to seeing how it performs. My biggest concerns are lack of weatherproofing and how it will affect phone battery life. I confess this is not the only little thermometer I am trialling this year. I have yet to decide whether to also buy the Govee 5074, or the more expensive SensorPush HTP.xw Wireless, that I notice has a higher degree of water resistance.