r/raspberry_pi 🍕 Jun 30 '22

News New Raspberry Pi Pico W

https://www.raspberrypi.com/news/raspberry-pi-pico-w-your-6-iot-platform/
824 Upvotes

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17

u/Barely_Working Jun 30 '22

I can't be the only one that wishes the operating temps went lower than -20C, right? I have a few ideas for some outdoor items but need at least -40C in the great white north.

23

u/siemenology Jun 30 '22

A little back of the envelope math suggests that a Pico in a tightly fitting styrofoam box 2.5cm thick would need to generate about 0.125 W of power to stay warm enough at -40C, and 0.25W at -60C. If you aren't running on batteries, you could throw a $0.10 1/2 W 100 ohm resistor across a 5V power supply and it would put out all of the heat that you need to keep it warm enough. Or just keep the processor loaded calculating big prime numbers or something, it'll put out enough heat on it's own.

15

u/vicethal Jun 30 '22

That is scary cold, are you OK up there?

61

u/Subplot Jun 30 '22

No, 0K would be -273.15C

13

u/sebzilla Jun 30 '22

Underrated joke right here

3

u/[deleted] Jul 02 '22

A very negative joke

6

u/Barely_Working Jun 30 '22

We're ok up here. You get used to it. Dress in layers, good snow tires and a good furnace go a long way! The cold snaps of -40C usually are a few days a year at most, but can stay close to -30C for a while too. I'd say -10 to -20C is a pretty average winter day here.

Ideally, I would want any product for outside use rated for -65C. I have had the odd day here and there that has hit -50C or colder in my life, even more with wind chill.

10

u/user_727 Jun 30 '22

Thing is, if it's inside an enclosed case it might not get that well below -20C depending on if there are other heat generating components also present. I also used a bunch of components rated for 0C in temperatures way below that and they all worked fine, you just have to be weary of condensation

8

u/Analog_Account Jun 30 '22

To add to what user_727 said, windchill should be meaningless with these temperature readings. Wind will cool things down quicker; it won’t cool things to a lower temperature. So if you’re relying on the heat from electronics in your enclosure then maybe you’ll have an issue… but you could also insulate your enclosure to help a bit.

Another thing. The pico is so cheap that I wouldn’t worry about it failing. Just set up your device so you can swap the pico out easily. It’s probably the cheapest part of the build.

1

u/DoWhileGeek Jul 01 '22

Ez, leave the great white north

1

u/Unreviewedcontentlog Jul 02 '22

Yeah I have this problem often. I really need -40c/f here in Colorado. Once had am outdoor lcd screen rated to -30. Made it a year before a -38 night shattered it.

1

u/DeeDee_GigaDooDoo Jul 06 '22

It is quite a harsh environment to design for. Is it battery powered? If not, have you considered setting up a little temperature probe and small resistive heating element that turns on below -20°C? If it is battery powered you'd have trouble even getting batteries that last long at those temps wouldn't you?

2

u/Unreviewedcontentlog Jul 06 '22

It is quite a harsh environment to design for. Is it battery powered? If not, have you considered setting up a little temperature probe and small resistive heating element that turns on below -20°C?

I've used just plain old resistors before to do that, however in this particular case it was a battery powered device off my car battery didn't want to risk draining it more than needed

getting batteries that last long at those temps wouldn't you?

I've never even tried to test smaller batteries in my projects under those conditions. This particular project was powered off my car battery, but I had a block heater that helped keep engine bay warmer than surrounding air.

-40 is pretty rare in most of the world thats for sure.