hand made ; alminium cap is for cooling

[hatahata]

i made hand made enclosure .

i use alminium cap ( for example drink's alminium cap  )  over copper heat sink
for radiating heat .





wood is easy to treat , and I hole acryl plate by small drill for metal and then bigger drill for metall .

if all plates are made by wood , the cost is cheaper ,
but the upper plate should be made by acryl plate at the point of it's beautifulness .

---
regards

[Boring]

I'm sorry to ask, but what is the function of the cap on top of the copper heatsink?

[hatahata]

the next is made by someone not me .

[pfeerick]

I'm sorry to ask, but what is the function of the cap on top of the copper heatsink?

Probably to give a larger surface, thus making it so the heat from the heatsink can escape quicker, and thus the make the heatsink able to 'sink' more heat. I don't know how effective it would be... but hey... any improvement is is a gain, especially when you have the space and a cap that is only going to be chucked in the bin! 

[Boring]

That is why I ask. The contact area with the copper heatsink looks so small. I was wondering if this is not constricting the airflow.

Can you post cooling results with and without cap?

[pfeerick]

That is why I ask. The contact area with the copper heatsink looks so small. I was wondering if this is not constricting the airflow.

Can you post cooling results with and without cap?

I'm happy to be proved wrong, but I wouldn't expect it to so much restrict airflow (we are talking about passive cooling here, after all) but to increase the area over which heat is dissipated, which is the whole idea of a heatsink in the first place... hence I would expect a couple of degrees drop in temperature allowing for longer periods of high CPU load. 

However, that is all semantics until someone can post some results. I can't as I don't even have a heatsink on mine!

[hatahata]

i try .

Code:

pi.bat
#!/usr/bin/env python
def f(x):
  return 4 / ( 1.0 + x**2 )
n = 10000000
sum = 0
step = 1.0 / n
for i in range(0, n):
  x = ( i + 0.5 ) * step
  sum += f(x)

pi = sum * step
print pi

Code:

temperature.bat
cat /sys/class/thermal/thermal_zone0/temp

with alminium cap


debian@pine64pro:~$ ./pi.bat ; ./temperature.bat

3.14159265359
46


ebian@pine64pro:~$ ./temperature.bat
40
debian@pine64pro:~$ ./temperature.bat
40
debian@pine64pro:~$ ./temperature.bat
40
debian@pine64pro:~$ ./temperature.bat
40


without alminium cap
debian@pine64pro:~$ ./pi.bat ; ./temperature.bat
3.14159265359
47


only 1 degree effect !
i am dissapointed and understand big alminium heat sink of odroid-c2 .

[Boring]

Thanks for sharing the results. Only 1C is a bit disappointing

[hatahata]

1 C is too miserable .

so i insert copper coin between copper heat sink and alminuim cap .
and i try

Code:

debian@pine64pro:~$ ./pi.bat ; ./temperature.bat
3.14159265359
41
debian@pine64pro:~$ ./temperature.bat
36
debian@pine64pro:~$ ./temperature.bat
36

good result

copper coin is about 0.1 dollar (10 yen) .
alminium cap press copper coin and fix coper coin .

alminium cap
heat conducting sheat(for attaching)
copper coin
heat conducting sheat
copper heat sink
heat conducting sheat
CPU

-----
regards

[pfeerick]

1 C is too miserable .

so i insert copper coin between copper heat sink and alminuim cap .
and i try

Code:

debian@pine64pro:~$ ./pi.bat ; ./temperature.bat
3.14159265359
41
debian@pine64pro:~$ ./temperature.bat
36
debian@pine64pro:~$ ./temperature.bat
36

good result

copper coin is about 0.1 dollar (10 yen) .
alminium cap press copper coin and fix coper coin .

alminium cap
heat conducting sheat(for attaching)
copper coin
heat conducting sheat
copper heat sink
heat conducting sheat
CPU

-----
regards

Thanks for the data, that was great! What happens to the temperature after the coin has been on for a few minutes? There will be an initial drop in temperature when you put the coin on (if it is cooler than then heatsink) as it will have to warm up. I would expect it would settle to the same temperatures as before. A heatsink can really only slow down temperature spikes - if your pine64's cpu is loaded for extended periods, it will eventually overwhelm the thermal mass of the heatsink, which is when you need to consider a fan / active cooling. 

That is of course, unless you go for the extreme heatsink as was done in this video.