I am currently developing a sensor box and plan on running it outside. Temperatures can get as low as -40 degrees F and once my box reaches an internal temperature of 32.18 degrees F it fails to read the sensors attached to the Raspberry Pi. Now the Raspberry Pi board still works, and records nothing once the temperature dips below 32.18 so I am wondering if the GPIO pins have a minimum temperature range of operation or if it's a component on the Pi board that is causing this. I am stumped and would really appreciate the help here. Thanks.
Asked
Active
Viewed 213 times
4
-
1I think it may be the sensor. Can you find specs on it and see what min temp is. Outside of that, you may need a voltage tester, or possibly a test light to check the pins when you run into problems.... And dang. I guess I should stop bitching about the feels like - 17F we have been having. – geoffmcc Feb 16 '15 at 19:22
-
Joe is saying, I believe, that the pi temperature is the issue and not the sensor temperature. Is the sensor located away from the board (I'm thinking maybe its an I2C sensor, like this https://learn.adafruit.com/adafruit-mcp9808-precision-i2c-temperature-sensor-guide/overview ?) You could test it with the Pi in a freezer and the sensor outside in the warm, or vice versa. Your threshold is oddly precise, are you measuring that with a different sensor? – greggo Feb 16 '15 at 19:38
-
It could be the power supply is going awry at the cold temperatures, perhaps enough to make the I/O stop working but not enough to cause other problems. Doesn't seem too likely, but maybe worth checking. – greggo Feb 16 '15 at 19:40
-
@greggo yeah I was looking at it as -32 since he before mentioned can get as low as -40. Probably too cold for pins, since pi still working. Like I said before, voltage test on pins or possibly a test light should tell you if pins are getting power in the low temp. Especially now that I think of it, 32 is freezing point. I suspect the pins now. – geoffmcc Feb 16 '15 at 19:47
-
Seems like condensation could become an issue too with temps like that. I haven't played with sensors yet, but I wonder if there is something that can be done to insulate the box, without effecting sensor reading. – geoffmcc Feb 16 '15 at 19:56
-
1Hey guys, thanks for the responses. The sensors are SEN-11050 temperature sensors and they are suppose to work in cold temperatures as low as -55 degrees Celsius. They are connected through CAT5 jack and then are soldered into a bread board which is connected to the pi through a pi cobbler. I agree with the idea that the GPIO pins are the problem, and plan on using a voltmeter to see if power is being sent to the sensors. Have any ideas on how to solve this? Do you think I'll have to add internal insulation to improve the time it lasts? – Joe Feb 18 '15 at 01:11
-
It could also be a clocking issue. One of the biggest temperature issues with chips and boards is that the clocks drift away from eachother if one is warm and one is cold, OR if they are both cold they drift at different rates. One solution is to slow down your clock rates a lot so that the %drift won't be as large compared to a bit width. Another solution is to sense when you are cold and try tuning/pulling one or the other clocks (more information needed for this approach) – benathon Mar 27 '15 at 03:16
-
@Joe did you check the answers below and find any that're appropriate? – Doug Edey Jul 22 '15 at 11:48
2 Answers
1
From a discussion on the RPi Forums, the operating range is -25C to +80C, -20F is -28C, so you are outside of the operating range.
I have noticed this with my Pis too (I'm in Canada and they are in the garage), I use a lightbulb to warm up the box that the pi is housed in so it survives.
Doug Edey
- 194
- 5
0
Given that the concern here is about the temperature of the pi being too low, the logical answer in this situation is to provide sufficient insulation to allow the pi to keep itself warm under these environmental conditions. Then retest the external temperature sensors.
Don't add too much insulation because the pi may then overheat and to this end you may find it useful to measure the temperature of the SOC as well as the external temperatures of interest. You may also want to make sure the box is suitably waterproof if the outside becomes warm enough to melt any surrounding ice.
-
Welcome to Stack Exchange. This is a questions and answers site, not a discussion forum. Please only post answers as answers, not related suggestions. – Gilles 'SO- stop being evil' Apr 09 '15 at 19:04
-
Gilles. My suggested answer may be brief but it is a genuine attempt to answer to address the OP question which in fairness is not well defined. The title is expresses the symptoms faced by the OP and is not actually a Question. However, the first sentence states that the OPs objective is to develop a sensor box. As a new member I did not have sufficient 'points' to add to all of the discussion above which I note has has not been critiqued. – AlgoaBay Apr 11 '15 at 15:09
-
The Op also commented later to ask whether adding internal insulation would improve the time it lasts? My response could have been better worded but it helpfully reminds the OP that the PI generates heat itself and suggests that additional insulation would be worth trying. Have you got a better answer? – AlgoaBay Apr 11 '15 at 15:27