Troubleshooting • rpi 3A+ “/dev/ttyUSB0 not found over a time” for no apparent reason

Hi,

I’m using the Raspberry Pi 3A+ module. For a long time, I’ve been running a Node.js-based project that continuously reads data via the USB port. Occasionally, I encounter errors like:

> **“/dev/ttyUSB0 not found over a time”**

These errors sometimes disappear after a manual reboot, and other times the Raspberry Pi reboots itself automatically (it's programmed to do so if it can't receive data from USB for a certain period). I’m trying to identify the root cause of this issue.

One of my suspicions is that the USB device might not be drawing enough current. To monitor this, I’ve implemented scripts that use `vcgencmd get_throttled` and `vcgencmd measure_temp` to track power and temperature status.

I power the Raspberry Pi using an adjustable 3-step 24V–12/5V/3V 3A DC-DC step-down converter. To ensure it can handle higher power demands, I usually set the output voltage to 5.1V or 5.2V.

I don’t believe the issue is temperature-related, as the average operating temperature is around 40°C.

Here are the OS details of the model I’m using:

```
PRETTY_NAME="Raspbian GNU/Linux 9 (stretch)"
NAME="Raspbian GNU/Linux"
VERSION_ID="9"
VERSION="9 (stretch)"
ID=raspbian
ID_LIKE=debian
HOME_URL="http://www.raspbian.org/"
SUPPORT_URL="http://www.raspbian.org/RaspbianForums"
BUG_REPORT_URL="http://www.raspbian.org/RaspbianBugs"
```

I’d appreciate any insights or suggestions you might have.

Statistics: Posted by cemtzn — Mon Jul 28, 2025 11:55 am

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