Page 1 of 1
12v fan port always shows 0v across pins
Posted: Mon Oct 15, 2018 10:18 pm
by mmm
How is the 12v fan output turned on? By default it seems to show 0 volts across the 12V and GND pins and the wiki only says that 12V is "controlled by GPIO4_C6/PWM1" but doesn't explain how to modulate it, or how to enable fan at all.
Also, where are we supposed to find fans with a male BM03B-GHS connector??? Why was such a completely non-standard and impossible to find connector chosen for the fan? All fans I've found online have the larger JST GH pinouts. What is the female connector's part #? Will a GHR-03V-S work if I solder it onto an existing 12v fan?
This board gets incredibly hot very quickly under load without a fan, it reaches over 90c and then just shuts down, so it would be best to offer a heatsink with a fan option and enable the fan modulation by default in the images.
Re: 12v fan port always shows 0v across pins
Posted: Wed Oct 17, 2018 10:17 pm
by Auberonicus
While I don't know about your particular use case, you could use pin 4 and 6 from the 40 pin gpio for a simple 5V fan. However, I am also trying to figure out the male connector for the fan header, so I can't offer much more assistance than that at the moment.
Re: 12v fan port always shows 0v across pins
Posted: Mon Nov 12, 2018 4:11 am
by Auberonicus
Just an update on the GHR-03V-S connector, I ordered some and they finally arrived, so I can confirm that this is the appropriate connector. So you should be able to replace a fan's standard connector with this one and it should work fine. As for how to actually turn on the port for the fan, I haven't figured that out yet as I have been running android on mine recently.
Re: 12v fan port always shows 0v across pins
Posted: Tue Jan 15, 2019 11:33 am
by g_arkady
Any idea how to make the fan work on android ?
Re: 12v fan port always shows 0v across pins
Posted: Tue Jan 22, 2019 12:06 pm
by g_arkady
ok, found it here
http://wiki.friendlyarm.com/wiki/index.php/FriendlyThings_for_RK3399#PWMin short
APIs for Accessing PWM
Export PWM0 to usersecho 0 > /sys/class/pwm/pwmchip1/export
Control a PWM fan's speed by setting the PWM's period and duty_cycle.echo 0 > /sys/class/pwm/pwmchip1/pwm0/enable
echo 50000 > /sys/class/pwm/pwmchip1/pwm0/period
echo 1 > /sys/class/pwm/pwmchip1/pwm0/enable
echo 45000 > /sys/class/pwm/pwmchip1/pwm0/duty_cycle
period: the more you set, faster the fan will be. range is about 30k to 300k
duty_cycle: the less you set, the more speed you get. range is about 1k - 49.9k
Re: 12v fan port always shows 0v across pins
Posted: Tue May 21, 2019 11:05 am
by kirkdis
can you please explain what to do in detail with the provided code and how to activate/execute the script?
Thanks
Re: 12v fan port always shows 0v across pins
Posted: Thu May 23, 2019 10:11 pm
by mopa9800
kirkdis wrote:
can you please explain what to do in detail with the provided code and how to activate/execute the script?
Thanks
While I don't know about your particular use case, you could use pin 4 and 6 from the 40 pin gpio for a simple 5V fan. However, I am also trying to figure out the male connector for the fan header, so I can't offer much more assistance than that at the moment.