switch to logger (more POSIX)

README.md

@@ -21,6 +21,7 @@ Scripts and documentation for setting up a Raspberry Pi (Zero W 1 or 2) for use
 - [Turning your Raspberry Pi Zero into a USB Gadget](https://learn.adafruit.com/turning-your-raspberry-pi-zero-into-a-usb-gadget/serial-gadget)  Official Adafruit guide to gadget mode to allow the USB port to be used as a serial console to connect to it.   We had trouble getting it to work in 2026 due to some changes in Raspberry Pi OS.
 - [Python gpiozero library](https://gpiozero.readthedocs.io/en/stable/) a simple interface for working with GPIO devices
 - [CircuitPython Libraries on Linux and Raspberry Pi](https://learn.adafruit.com/circuitpython-on-raspberrypi-linux/installing-circuitpython-on-raspberry-pi) This is one option for GPIO, I2C, SPI, and PWM access in python.
+- [Comparing Rasbperry Pi python interfaces](https://raspberry.tips/en/raspberrypi-tutorials/raspberry-pi-gpio-python)
 
 ## For the Future
 - [Setting up Zeroconf to use local names (.local) to access your Pi](https://learn.adafruit.com/bonjour-zeroconf-networking-for-windows-and-linux): this does not work on iot-research because multicast and MDNS are broken.

Scripts/gadget.sh

@@ -2,10 +2,34 @@
 # Adapted from
 # "Using OTG mode on Raspberry Pi SBCs"
 # https://pip-assets.raspberrypi.com/categories/685-app-notes-guides-whitepapers/documents/RP-009276-WP/Using-OTG-mode-on-Raspberry-Pi-SBCs
-sudo modprobe libcomposite
+
+# This script only works if you are running it as root
+if [ $(id -u) -ne 0 ]; then
+    echo "Please run as root or use sudo"
+    exit 1
+fi
+
+
+# Is the dwc2 overlay installed?  Nothing will work if it isn't.
+if lsmod | grep -q "dwc2"; then
+    echo "DWC2 module loaded, setting up OTG gadget serial and ethernet" | logger -t $0 -p info
+    echo "DWC2 module loaded"
+else
+    echo "DWC2 module missing.  Aborting OTG setup." | logger -t $0 -p info
+    echo "DWC2 module missing"
+    systemctl disable serial-getty@ttyGS0.service
+    exit 1
+fi
+
+modprobe libcomposite
 cd /sys/kernel/config/usb_gadget
+if [ -d "MyGadget" ]; then
+    echo "MyGadget already exists.  Aborting OTG setup." | logger -t $0 -p info
+    exit 1
+fi
+
 # Create our new gadget
-sudo mkdir MyGadget
+mkdir MyGadget
 cd MyGadget
 # Add some boilerplate data that the gadget needs
 echo 0x1d6b > idVendor # Linux Foundation’s USB VID. Replace with your own VID if required
@@ -30,6 +54,7 @@ echo "Config 1" > configs/c.1/strings/0x409/configuration
 ###  Remember to create the storage block device first
 ##  cd /root
 ### Example: Make a 256 MB file to act as "USB stick"
+##  Only create it once or it will delete the previous content
 ##  sudo dd if=/dev/zero of=drive.bin bs=1M count=256
 ### Create a VFAT file system on the backing store
 ##  sudo mkfs.vfat drive.bin
@@ -45,9 +70,14 @@ mkdir functions/acm.usb0
 ln -s functions/acm.usb0 configs/c.1/
 
 ## Ethernet (RNDIS and ECM)
+## Of note, this may cause the IP to show up as 127.0.0.1
+## and wireless to suddenly fail to connect
 mkdir functions/ecm.usb0
 ln -s functions/ecm.usb0 configs/c.1/
 
 ## USB Device Controller update
 UDC=`ls /sys/class/udc`
-echo $UDC > UDC
+echo $UDC > UDC
+
+# Enable the gettys
+systemctl enable serial-getty@ttyGS0.service