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by lmz19 hours ago |
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upvoteby willis93613 hours ago|
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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.
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upvoteby esikich9 hours ago|
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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.

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upvoteby spogbiper7 hours ago|
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I've used these: https://sensirion.com/media/documents/213E6A3B/63A5A569/Data...

They claim accuracy of +-0.2 c across a wide temperature range and in my use they seem to be. easy to find on a support board for under $10

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upvoteby esikich4 hours ago|
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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.
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upvoteby mrheosuper13 hours ago|
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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.
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upvoteby willis93612 hours ago|
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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.

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upvoteby MaxikCZ13 hours ago|
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> How is that relevant for the average buyer

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.

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upvoteby asutekku9 hours ago|
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Average buyer googles "best cheap zigbee temperature sensor" and reads this article.
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upvoteby mohamedkoubaa46 minutes ago|
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People who read ingredients lists of food are a tiny, parochial subset of consumers and yet they strongly influence what is on shelves.
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upvoteby cstrahan12 hours ago|
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The average person doesn’t read Hacker News, so why does it exist, and why are you here in the comments?

Similar reasons: the intended audience isn’t the average person.

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