The extra pin of each fan is a tachometer output. You can leave those disconnected or connect them to the unused GPIO pins for RPM monitoring (check out this tool). For my build I just cut off the fan connectors, soldered on extension wires and crimped female Dupont connectors onto the ends. I also reused the sleeve that came from the factory and secured it with heat-shrink to make the harness look tidier.
I appreciate your answer. I was able to make it work perfectly. I have a few more questions:
- Use this script for OpenWrt which reads all temperature sensors in hwmon and adjusts the fan speed according to the highest reading; you can dial in your own temp thresholds there
- Put the script into /opt (or any persistent directory) with the following command (if using Linux or macOS): scp -O /ā¦/fan_pwm.sh [email protected]:/opt/
- Make it executable: chmod +x fan_pwm.sh
- Make it run at startup: sed -i ā/^exit/i /opt/fan_pwm.sh &\nā /etc/rc.local
For a common mortal that is approaching this from a 0-knowledge perspective, how do I do this exactly? I was capable of making the script run from ssh, but I donāt know how to save that and make it run on startup.
- Rather than making the grounding strips by hand, order them to be laser-cut insteadāitās likely to cost less than your time spent measuring, drilling and cutting
Are there any CONS in not using the grounding strip? I installed everything without it, and itās working decent.
Oh, BTW, just for laughing a bit, instead of soldering the EMI shielding, I used superglue 
Regardless, before I was somewhere at 78/79 noise, now I sit at around 85. Itās still progress!
For a common mortal that is approaching this from a 0-knowledge perspective, how do I do this exactly? I was capable of making the script run from ssh, but I donāt know how to save that and make it run on startup.
If youāre creating the script on the system rather than transferring over:
apk add nano or ipkg install nano depending on your OpenWrt release, if not already installednano /opt/fan_pwm.shchmod +x /opt/fan_pwm.sh to make the script executablesed -i ā/^exit/i /opt/fan_pwm.sh &\nā /etc/rc.local to make it run on startupcat /etc/rc.local; you should see the line /opt/fan_pwm.sh &/opt/fan_pwm.sh & to launch the script without rebooting; you should hear the fans slow downluci-app-statistics and lm-sensors packages to track the temperatureAre there any CONS in not using the grounding strip? I installed everything without it, and itās working decent.
In my experience, the improvement from the grounding strips and EMI shielding together was marginal, but that could change depending on how congested your Wi-Fi environment is. I also hope the BE19 will be inherently less susceptible to noise to benefit from extra grounding.