We tested the board under several CPU loads and setups. The preliminar results:
SETUP | aprox. CPU usage (%) | max. internal sensor temp (C) | max. external IR temp (C) | aprox. current (mA) |
No heatsink | 20 | 61 | 67.3 | 840 |
50 | 69 | 74.4 | 920 | |
70 | 72 | 77.7 | 970 | |
100 | 76 | 82.5 | 1030 | |
One heatsink (15x15x15mm) | 20 | 54 | 57.8 | 840 |
50 | 57 | 62.0 | 920 | |
70 | 61 | 64.2 | 970 | |
100 | 63 | 67.4 | 1030 | |
2 heatsinks (one on each side) | 100 | 56 | 60.8 | 1030 |
Here you can watch a speeded-up video of the analysis:
We also tested a bigger heatsink (30x30x15mm) that keeps the temperature in the same range as the two-heasink setup, stable at about 56 C.
How do you keep the bigger heatsink in place? Also, can you please do a test of fan blowing through pandaboard with/without heatsinl?
ReplyDelete@ShadowPhoenix
ReplyDeleteIn the picture you may see a steel wire across the heatsink with two white "heatsink plastic push pins" stuck into the boart holes, one on each end of the wire. That wire keeps the heatsink in place.
With a big heatsink (from 30x30x15mm to 30x30x30mm) there is no need for a fan in a normal environment (no direct sun and ambien temp. of about 25-30 Celsius / 80-90 Fahrenheit), as the temperature never exceeds 60 Celsius at 100% CPU load.
If I use a heatsink (approximately same size) with thermal adhesive instead of using the steal wire will the result differ substantially?
ReplyDeleteI guess you mean a thermal sticker, which has a lower performance than thermal adhesive (epoxy), and much lower than thermal paste. However, for this application it should do the job, specially if you use a 30x30x30mm heatsink, and keep the board well ventilated.
DeleteI have purchased a pandaboard and have build a custom enclosure. I have linaro running well however what utility did you use to show the cpu temp. I am new the the ARM platform...
DeleteThanks
There might be some driver already (to be detected by lm-sensors).
DeleteBut at the time I did it I made a custom app with a hack found in the web (once compiled you have to run it as administrator): hardwarebug.org/files/omap4_temp.c
I wasn't able to find lm_sensors compiled for ARM. I will try the script you listed. Thanks for the help!
Deletecat /sys/bus/platform/devices/temp_sensor_hwmon.0/temp1_input
Deletewill give you the temp in mC (milliCelsius)