BeagleBone AI-64 active cooling

General Discussion
1

Greetings,

I am interested in using a BeagleBone AI-64 in one of my projects. Unfortunately, it is a bit too high with its heatsink attached. As such, I would like to know if anyone has some recommendations of some smaller active cooling solutions that could replace the heatsink. Is there an official fan for the BeagleBone AI-64 (I see that there is a fan connector).

If none are available, can the BeagleBone AI-64 be used without a heatsink without damaging it? Will thermal throttling prevent the SoC from being damaged by excessive heat?

Best regards

2

Given that the board runs at around 60C when idling, I doubt you will be able to run it without a heatsink.

The Ti EVM board uses a much smaller heatsink, a few mm’s larger than the chip, although it looks higher. A bit hard to tell from an image.

How much cooling you will need will depend on what you are doing, ambient temperatures and enclosure.

As far as I am aware there is no inbuilt over temp protection at the hardware level. I don’t think the kernel as is does anything but warn if the temp becomes critical either.

Yes you can fit a fan and you can use the fan header, or just power one from the USB port. I recently create a device tree overlay (BONE_FAN.dtb) with a fan section to automatically adjust the fan speed connected to the header based on the temperature (4 speed settings). This relies on the automatic PWM export script NOT exporting the pwm channel. Alternatively you can not load the overlay and setup the pwm channel yourself and set the speed/adjust the speed yourself.

3

Thanks @benedict.hewson! Do other chips need a heatsink? Would placing a fan only on the SoC be enough?

4

J721EXSOMXEVM module

Similar specs to the BBAI64. I assume the heat sink is only required for the processor.

5

Alright. Thanks @benedict.hewson! :slightly_smiling_face:

6

Can you provide BONE_FAN.dtb file.
As I am new to BB AI64, Please let me know where to run this?

7

It’s shipped by default… src/arm64/overlays/BONE-FAN.dts · v5.10.x-ti-unified · BeagleBoard.org / BeagleBoard-DeviceTrees · GitLab

Just update:

sudo apt update
sudo apt-get dist-upgrade
sudo reboot

Regards,

1 Like
8

Unfortunately it is not that straight forward to use the overlay.

There is a UDEV rules that automatically exports all PWMs that are enabled. This stops the overlay from working.

To get around this you need to remove the UDEV rule from both the file system and the init ram disk that is loaded at boot.

I think the fan will spin if you don’t do this, but it will be spinning at full speed and probably be quite noisy.

The overlay will spin the fan a lot slower and adjust the speed based on the temperature. If you edit the overlay you can adjust the temperatures/fan speed values to suit your needs.

Alternatively as the PWM is exported you can write some software to control the PWM from userspace.