next topic »

[on:]

HELP
Im just wondering if anyone has tried using an UNO in ambient temperature ratings below the rated 0 celsius. i currently have one in a crane that is controlling the swing. it is up in saskatchewan where the temperature was at -30 celsius one day this week. during operation of the crane it swang irradically and actually posed a safety concern. im currently trying to implement a small heater into the electrical enclosure with a thermostat mounted in the cab of the crane. my hope is to have the operator turn the key on, which will start the heater and thermostat. the thermostat has a readout for both the current temperature in the enclosure as well as desired temperature reading which will allow the operator to wait until the enclosure temp is up high enough into the UNO's operating range. im going to try to have the heater maintain an enclosure temperature of around 5 degrees, i believe this will solve the problem. has anyone else had similar things happen when operating out of the UNO's range? keep in mind that i am not able to do any testing since i am few hour plane ride away. thanks... ideas???

[Reply #1 on:]

The heater sounds like a good idea. In my opinion, as
long as you stay within the specifications, it should be
fine. But I haven't tried it, so you could try testing it
in a home freezer?

[Reply #2 on:]

Couple Questions:

How much more electronics isthere? just UNO?  Must be quite some interfacing to control valves etc...
Can you separate the UNO problems from the Interface problems??

Are you using USB communications?

The ATMEL chip MAY be available in a wider temperature range; need to check with ATMEL. Might not be available in the DIP package though. But you might be able to replace the surface mount chip on a UNO SMD or a Seeeduino with a "Automotive Temperature Rated" ATMEL chip.  If you're not using USB, the rest of the components on a UNO may not be a problem. 

Also, are you sure the atmosphere in the box is non-condensing at the low temperature? Not likely.. Probably have some frost somewhere at that temperature, unless you have good dessicant in the box . 

You really need to evaluate ALL the electronics for use at -30C..

Heating the box is OK, but if moisture condenses overnight, it will have to heated for a while to dry out.. Insulation plus a separate rechargeable battery to keep it warm overnight might work.

I worked on the IBM Industrial Computers and the IBM "Gearbox" and this cold weather operation was not a trivial question... 

You better have a big Emergency Off button on this puppy :-)

Let us know how you make out.. very few people are asking this pretty important (for the future) question.

[Reply #3 on:]

I have a minor amount of experience here, I'm running my ReallyBareBonesBoards at 3.3v 16mhz (overclocking, technically), and they start to crash randomly at 38*f, and lock up completely at 36*f.
It sounds like more voltage allows colder operation, but if you're already at 5v there isn't much more you can give it before you're overvolting the chip.

Looking for a board that has a larger temp range would be the best plan, but a heater in a box should work as well.

[Reply #4 on:]

I have a minor amount of experience here, I'm running my ReallyBareBonesBoards at 3.3v 16mhz (overclocking, technically), and they start to crash randomly at 38*f, and lock up completely at 36*f.
It sounds like more voltage allows colder operation, but if you're already at 5v there isn't much more you can give it before you're overvolting the chip...

You're not running a USB interface, so it's clearer now that we are talking about the ATMEL chip's behavior at low temperatures.

My son designs Wind Energy dataloggers that run on very cold mountaintops (http://nrgsystems.com). With ATMEL chips.

...SO I'll ask Him