Ambient Temperature Thermistor


 

Bob Ivey

TVWBB Emerald Member
Having just completed my first HM4 build and having read so many different posts, I have a few thoughts concerning the thermistor.
Everyone mentions the difference in temp inside the case. Since that is normal because the Raspberry Pi is a computer and does generate heat, why not do one of two things. The first option would be to drill a hole in the case and put the thermistor in the hole sticking out a little bit and using a dab of silicon on the inside or the hole keep the thermistor in place and to help insulate it from the heat inside the case. The second option would be to get a plug like the probe plugs and solder the thermistor to the plug and then screw the cap back on. When this plug is plugged in it will give you the ambient temperature that is not effected by the hot air inside the case. The only downside to this approach is the plug will be small and can get lost easily. One solution for this is to either paint the cap a bright color or to use a label machine and make a flag type label indicating ambient temp probe. One of my label makers uses a tape that is bright yellow. Much harder to loose.

Just my two cents. What do you think? Good idea or bad?

If this idea has already been brought up by some else they have my apology. Did a search about this but could not find any mention of these ideas. Thanks
 
Yeah ideally you'd put the ambient sensor somewhere it can measure ambient temperature rather than inside the case. When the instructions were first written, there wasn't a standard case yet so it just says to solder it the way it is shown. You can mount it however you like, in fact I might go drill a hole in my main device right now. I would not silicone it in place though as it would make the removal of the HeaterMeter board pretty difficult. I think if you just poke it through it should be fine. The case doesn't heat up all that much, and you'll probably have more error introduced by the sun reflecting onto it.
 

 

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