I’m wondering what is the make/model of the fan? I have feeling the ones we have might die soon so I would like to order replacement part in advance.
In general no matter of the quality/make the small form factor fans have to have high RPM to get some airflow and combined with small ball bearing makes them fail pretty quickly. Compared to large fans where the bearing can be larger and more robust and needs only very low RPMs to get the same airflow. The lifespan of the small fan in general is much lower compared to larger fans. And have feeling this will be the same case with unleashed boards.
Most of the units were mostly stationary and they sound okish. One unleashed unit was more portable and that one started making sounds like when the fan is going to die. Probably traveling didn’t helped.
Do you have any clue what ratings the connector has, i’m tempted to put 120mm fan running idle over the whole board. The big fans are pretty power efficient but still it might be more than the 25mm fan.
Hi,
I recommend 60 mm case fans, which are also available with 5V power supply as an exception. There is a company that supplies fans with some adapters for adaptation to the respective conditions. Actually these are 4 wire PWM fans, but they also work with only 2 connected wires. Then you can’t measure the speed, but with 2 wires it is at maximum, so 3000 rpm. However, the fans are almost inaudible. I would also recommend a dust filter.
Yes noctua is great brand. No problem for me to make small RPM controller with a ATtiny (probably should be possible to use HiFive1 as well). I would give it try, except the dust filter.
If a 5V fan is used, the adjustments to the 12V are omitted, which simplifies the circuit. Only the pull ups against 5V and a diode are needed. I use cheap Arduino Pro Micro (ATmega32U4), from China. The 25kHz I create after an example by Edgar Bonet. He has released the short program on StackExchange in response. Set PWM frequency to 25 kHz It’s the code in the second response.
// PWM output @ 25 kHz, only on pins 9 and 10.
// Output value should be between 0 and 320, inclusive.
void analogWrite25k(int pin, int value)
The photo shows a test setup with a Leonardo powered via USB from the Raspberry 3 B+, which is also to be cooled. The housing is made of aluminium and also serves as a passive cooler, which is sufficient up to 3 B, but no longer for the 3 B+.
I’m having the same problem, the CPU fan sounds like the bearings are dying.
I don’t have a case, is there an off-the-shelf case that fits the hifive unleashed board where I could mount a fan?
I would say many of small fans have tendencies to develop these issues (despite their quality).
If you have some case for it already and it’s easy enough to modify I would suggest that if you will be getting replacement, to replace it with bigger, but much slower fan (which last much longer, even the low quality brands).
