Do RPi's running ADSB tasks need heat sinks?


#1

Hi all,

Having just added JP’s ADSB Reciever image, and lignumaqua’s heat mapping / max range etc - it would seem these RPi’s are doing a lot more than just running a word processor these days!

That said, CPU % shows c10% on average - but the CPU temp graph looks rather warm, reaching 100 F?

Does anyone use or recommend heat sinks on the RPi2?
(Cased, not over clocked.)

That said - is only using a small % of CPU, is there any benefit to

a) Overclocking
b) Re-allocating graphic memory if it’s running headless (mine is)

?

https://docs.google.com/drawings/d/16yH-22x5DmdJg5M3GQJX8qynBdc2nJCXPN5mS-7MDtE/pub?w=960&h=720


#2

That said, ADSB shows max 20% CPU scale, while the overall CPU % shows less than 10% being used…

Am I right to think that overall, c10% of the CPU is being used, and of that 10%, 20% is being used by adsb processing?

https://docs.google.com/drawings/d/1w-5kTOtCnbdvGG_hp9qIK6ojZFU0hItxF-qqpJj5BgI/pub?w=960&h=720


#3

The dump1090-generated CPU numbers are measuring (CPU seconds / realtime seconds) i.e. fraction of one core used.
The system-wide graphs are probably measuring CPU use as a fraction of total system capacity, i.e. 1 core fully used = 25% if you’re on a Pi 2 which has 4 cores.


#4

I have one running next to a basement window that gets fairly cold. It barely gets down to 90F when 10F outside.
The one behind a dresser in the bedroom sits at 120-130F for the past month.

I haven’t left an RPI3 running with piware for long enough to get any stats(once piware worked I have been using it for testing stratux. no luck so far).

I google of “do rpis need heatsinks” reveals differing opinions.

One is that the heatsinks done’t work and actually insulate the CPU causing it to heat it.
(partially caused by crappy heatsinks and thermal compounds)
reddit.com/r/raspberry_pi/c … eat_sinks/

One comment from raspberrypi.org suggests maybe for an overclocked RPI3
raspberrypi.org/help/faqs/# … ceHeatsink
"3. DOES IT NEED A HEATSINK?

You should not need to use a heatsink, as the chip used in the Raspberry Pi is equivalent to that used in a mobile phone, and should not become hot enough to need any special cooling. However, depending on the case you are using and the overclocking settings, you might find a heatsink to be advantageous. We recommend the use of a heatsink if overclocking the Model 3B. Of course, if you just like the look of one, you will not hurt the Raspberry Pi by placing an appropriately-sized heatsink on it. -Performance and Cost Considerations -Top.

8. What is its operating temperature?

The Raspberry Pi is built from commercial chips which are qualified to different temperature ranges; the LAN9512 is specified by the manufacturers as being qualified from 0°C to 70°C, while the AP is qualified from -40°C to 85°C. You may well find that the board will work outside those temperatures, but we’re not qualifying the board itself to these extremes. -Performance and Cost Considerations -Top"


#5

FWIW I have about 6 Raspberry Pis running 24/7 running various tasks including as a caching DNS server for the house, a weather server and so on. None of them have heat sinks. Some of these have been running for over a year. Months and months of that without even a reboot. Yep, they get warm, but they seem solid. What fails are the SD cards, and that’s not because of the heat. :frowning:


#6

@lignumaqua - DNS Caching server? :wink: Lol - yes, I’d thought of something similar as well… man after my own heart!

Dont think I’ll bother with heat sinks then…

BTW - I have the RPI2 running ADSB stuff, and two Zero’s just waiting for me to decide which project to put them to… :wink:


#7

@jonHawkes2030

Thanks for that - just what I was looking for!

  1. What is its operating temperature?

The Raspberry Pi is built from commercial chips which are qualified to different temperature ranges; the LAN9512 is specified by the manufacturers as being qualified from 0°C to 70°C, while the AP is qualified from -40°C to 85°C. You may well find that the board will work outside those temperatures, but we’re not qualifying the board itself to these extremes. -Performance and Cost Considerations -Top"


#8

As another data point. I received a Pi 3 today and installed Dump1090 etc using the jprochazka scripts. Here’s an FLIR image of the device running. Nothing on the Pi3, including the Processor (no heatsink) has exceeded 50 C yet. The dongle (NooElec NESDR Mini 2) gets to about the same.

This is at room temperature, sitting on my desk with no enclosure, so I’m sure it will go up some from here.


#9

Very nice! Do you have a similar FLIR image of your other Pi models?

I placed mine in my attic, so by this summer I expect it to reach 50 C when it’s not even turned on :slight_smile:


#10

I’ll take a comparison shot of the Pi running my main PiAware.

I did have mine in the attic too, but the potential summer temperatures here scared me so I drilled through and put the Pi on the top shelf in a cupboard in a bathroom. Still fed power and RF from the attic, so it was an easy mod.


#11

Humans run at 98.6 F with no extra heat sinks. 100F is barely warm to the touch.

My Pi runs at between 47c and 53c in it’s outdoor enclosure. 24/7.