One of the things I never see in reports like this is what sensor is being used (is it a Bosch unit? Sensiron? Plain thermistor? Pixies and Fairy Dust? Some bodged together 1wire deal?) and what MCU (Nordic? Espresif? Microchip? Something else?) as those have a huge bearing on what the sensor is actually capable of, and would say a lot about precision/accuracy and battery life.
How is that relevant for the average buyer (as much as these things have an average buyer anyway)? Precision, accuracy, and battery life is helpful info but the inner components are an irrelevant detail. It's not like having a high quality part prevents them from using it wrong anyway.
The datasheet gives you much better fidelity data than an N=1 test. You'll never know what the tolerance is if you're just looking at one unit. Presumably the average buyer cares if they expect the temperature sensor to be 5% off on the unit they buy. The accuracy of all of these sensors have ratings, but they are often just copying the value on one component and not even considering a stackup. Devils lie in details.
Regarding accuracy, it's been about a decade, but I did some embedded projects related to accurate temperature measurements back in the day. From what I recall, anything sensor that is < $100 or so is going to be 5% margin of error at the very best, and regardless of price, you're going to have to calibrate it and figure out the curves in your ADC, it's not going to be linear. Additionally, just the act of measuring will heat your sensor slightly so that will need to be taken into account as well.
In short, if you need less than a couple degrees of accuracy, it's going to take a bit of tinkering. I wouldn't trust a $1 sensor for a tropical fish tank, for example, but probably good enough for a home thermostat.
That tracks somewhat with what I remember. I was working on process control for an industrial washing machine in a hot and humid environment. I think the extreme temp and humidity is what made it difficult, but those error margins do look great for the cost.
The datasheet will gives you absolute best case scenario. Like current consumption in sleep mode, or what register to set for best accuracy. It does not mean the Firmware will do exactly that.
The datasheet gives you the 3 sigma worst case for accuracy.
For power consumption a system power tree needs to be constructed and that will set the bounds that firmware can achieve. That would be better than trusting the manufacturer but a real test is best.
Avg buyer wont read a token of tests before buying whats marketed best.the whole point in test like these is to provide non-average buyer with info average buyer doesnt care for.
For most of these small sensors you'll need to crack open the device to find out exactly what hardware is really there. More than once I bought at different times apparently identical Zigbee sensors which behaved very differently and it turned out they were different inside despite having the same model name. Probably a hardware revision thing but with no clear markings. Manufacturer couldn't find some component anymore or not for a good price and instead redesigned the device.
Those who care about the internals are techies who maybe want to build their own or are very curious. Most buyers don't care about that, they care about how well it works in practice. Just like they don't care what RAM chips are used in their phone or computer, what modem, what screen panel, what camera sensor, etc.
If they change components the properties in this test would also change so not sure I get your point other than that any test is useless since manufacturers change stuff without telling the buyers pr changing model numbers.
Unfortunately a lot of these tests are useless because the manufacturers often change the insides without warning. It’s better when they mark different hardware revisions but still not great because reviews rarely get an update.
I have a bucket of devices which don’t do what I hoped they’d do because they were different from what the reviews said. And not just IoT unfortunately. Some do a better job at flagging these changes, some don’t.
But in the end taking the common case that the product is what it says on the box or that the changes have no impact on how it works, most people don’t care about the name of the chips. Not unless they are very keen on the tech and then there are more tech-oriented niche sites that might provide this.
But name of chip would be a decent way for people to get a rough idea for if the manufacturer have change it so to me that seems like a useful piece of data.
I understand you, more information is better. I meant this article probably targets a different audience. Other articles [0] on the site focus on specific models and take this extra step, where the information is published or the devices can be easily explored. E.g. in that other article they mention the SNZB-02P has a Sensirion SHT40-AD1x.
There's nothing wrong with occasionally having these "roundup" articles targeting a larger audience.
I say this as someone who built multiple similar sensors around the house myself (except far less pretty or energy efficient than the commercial ones). Sometimes you just want a roundup and a quick comparison.
There's no guarantee that the COOL SMARTHOME SENSOR V1 has the same sensor or MCU like the COOL SMARTHOME SENSOR V1 that I can buy. Sure, it's interesting to know, but it's not too usefuly
Chipset models only form a weak lower bound on crappiness.
You can certainly wreck connectivity with bad and old firmware. Similarly, housing design, PCB thermal isolation, not putting the sensor next to the MCU, measurement averaging settings, etc. all are going to affect accuracy even with the same sensor (particularly dynamic accuracy).
I think buyers care more about accuracy and resolution than which sensor. If it’s accurate, with hugh resolution and has good battery life, do you care if it’s Bosch or A Chinese name you’ve not encountered before?
I don't so much care if it's a Chinese knock off or a real deal Bosch BMP, but if you're interested in measurements that are better than vague vibes, the difference between a cheap poopoo glass thermistor hooked up to the noisiest 8-bit ADC (let's be real about what's actually in there), sets a real limit on anything that device will ever be capable of, especially if you have more than one. If a device has got a real deal BMP581 (yes that's a pressure+temp sensor, but let's roll with it) that's a whole other ballgame, and yeah they could have messed up the housing or it could brown out, have bad lower power characteristics, or bad firmware, but that BOM difference says a lot about what the engineer who designed it probably thought the device should be capable of.
