Temperature variations in TMP117

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Hey all. I have 3 TMP117 sensors which I’ve set up in various parts of the house on a Pi each, and there seems to be a bit of a variation in the temperatures? One is bang on when compared with an analog thermometer, but the others are 1-2 degrees out. Any ideas?

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Hi @Hamish159997, welcome to the forums :slight_smile:
How are you comparing the devices? Is it by moving the same thermometer between them and allowing it to settle?

It’s likely that the reading reported by the TMP117 is more accurate than other commonly available sensors - 0.1°C from the factory with no calibration required is no joke :smiley: it’s a pretty amazing device!

I’m curious to hear what happens if you put all three sensors in a box together and allow them to settle. Other curious forum members have done this in the past and confirmed the sensors agree with high precision.

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Hi Hamish,

I can confirm Michael’s thoughts, I’m currently using 4 of these sensors for various parts of my house, and putting them next to each other in in an insulated box met the spec given by TI of ±0.1 degrees absolute accuracy (and therefore they all sit in that range).

here’s a quick and dirty chart:

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I can’t upload the raw data on this forum, but let me know if you have any questions.

You’d be surprised how much air currents, sun and other local phenomena affect temperature, here’s how noisy mine are typically when in open air or in vented enclosures:

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Thanks for the prompt replies! I have been walking a thermometer between three rooms, and comparing the temperature being returned by each sensor, after a reasonable settling in period. I’ll try and put them all together in one room and see what we get, that indeed will be the ultimate test. Cheers!

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Hi Hamish
I think the guys mean for all the sensors to be in one BOX, not room. A room could still give you differences.
Cheers Bob

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Hi Hamish,

I think Bob is right here, these sensors are so sensitive you can pick up someone walking past them. I suggest bubble wrap or some other packing around the sensors, and the sensors as close to each other as you can get them.