I'm trying to run my Pi Zero W as a motion detecting camera using RPI cam web interface but it keeps hanging after a few hours at most. Before it hangs, it can record motion detect videos and upload them to google drive using rclone. I left it running in my office over the weekend, and now that I've come back it's happened again.

Without pulling the plug, I can observe the following:

  • Activity light is solid green
  • It's not connected to wifi

My questions are:

  1. Without a hard power cycle, is there any way I can check if the whole system is hanging or just the wifi?
  2. If I do pull the plug and plug it in again, where can I look for clues as to the cause of this issue?

Pi Zero W, Raspian Stretch 4.14.98+

  • 1
    system log files is a place to start looking for system logs Mar 18, 2019 at 0:14
  • Thanks. I'm definitely going to update the settings on journalctl per your advice on my other question. Just want to see if I can find out what it's doing right now before I reset it. Will hdmi show anything if I'm running stretch light?
    – John Haire
    Mar 18, 2019 at 0:29
  • that wasn't my advice :p Mar 18, 2019 at 0:36
  • 1
    Look in /var/log/syslog. Check your power supply isn't too weedy - the camera is power hungry. Run free > /var/log/free.log every minute from root's crontab write that with sudo crontab -e. After the system fails take a look at that log to see if there's a memory leak.
    – Dougie
    Mar 18, 2019 at 7:05
  • Not to throw cold water but I thought the log files were not persistent by default so by looking through them after a reboot you'd only be getting logs since the reboot? Correct me if I'm wrong. Mar 19, 2019 at 20:01

1 Answer 1


You can use the serial debug interface to get a console on the Raspberry Pi. To use it you need a USB to Serial adapter like one from amzon - RPi USB/serial adapter. You do not need the most expensive one. I have made very good experience with one of the cheapest from China. To use the serial console you have to add a line to /boot/config.txt


Then you can connect the adapters cable black to pin 6 (Ground), white to pin 8 (GPIO14=TXD) and green to pin 10 (GPIO15=RXD). Never connect the red cable. Now you can use a serial console program to get connected to the RasPi as long as it is running. For example on a linux Laptop you can use screen:

laptop ~$ screen /dev/ttyUSB0 115200

But also on MS Windows are serial console programs available.

Now you can examine what's wrong with your RasPi and why it hangs.

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