rasp.local

Project page for my personal Raspberry Pi (Original Model B).

Why?

My Raspberry Pi is very old and cannot run OctoPi. As a compromise, I'm trying to build a lightweight solution for monitoring print jobs and (hopefully) starting/stopping print jobs remotely.

After all, my Pi is old, not broken 😉

Build the base image

Install the Raspberry Pi Imager and flash an SD card with Raspberry Pi OS Lite (32bit). It is recommended to use key-based authentication for SSH.

Installing TP-Link AC600 Nano driver on Raspbian (32bit)

The original Raspberry Pi Model B does not have a wifi card installed. I chose the TP-Link AC600 because of its compact form factor and dual-band support. This section outlines how to install the device drivers for Archer T2U Nano.

Note: This section is largly based off of this how-to guide.

Install the build dependencies

sudo apt install dkms git build-essential libelf-dev

Clone and build the driver

git clone https://github.com/aircrack-ng/rtl8812au.git
cd rtl8812au/
sudo make dkms_install

*Note: The build may take a while to run (~1 hour for me). Go grab some ☕

Check to make sure the install was successful:

sudo dkms status

You should see an entry for 8812au with an installed status. If so, unplug the wifi module and plug it back in. The green lights on the module should light up.

Configure Wifi SSID/Key

Use raspi-config to configure the wifi connection. The pi should appear as a wifi client on the network about a minute after the config is saved.

Disconnect the Pi's ethernet cable, then veryify that you can still connect to it via ssh.

Configuring the Webcam

I used the Logitech HD Laptop Webcam C615 for the camera. Plug it in, and verify that the device can be found:

lsusb

Set up the Stream

I used mjpg-streamer as my stream server. mjpg-streamer is a lightweight streaming application specifically designed for machines with limited resources. It is perfect for my 700Mhz raspberry pi, and typically consumes less than 15% of the available CPU when streaming at 15fps.

Follow the setup instructions in mjpg-steamer.

After the package has been built, cd into mjpg-streamer/mjpg-streamer-experimental and run:

export LD_LIBRARY_PATH=.
./mjpg_streamer -o 'output_http.so -l 0.0.0.0 -p 8083' -i 'input_uvc.so -f 15 -r 640x480'

This launches a webserver listening to port 8083. Next, open a web browser and navigate to http://<hostname_or_IP>:8083/?action=stream. You should see the camera streaming to the browser 👍

Tuning the webcam

mjpg_streamer supports configuring the framerate and resolution via the -f and -r options, but sometimes this isn't enough. To discover more camera options, run v4l2-ctl -l to list the available options:

                     brightness 0x00980900 (int)    : min=0 max=255 step=1 default=128 value=128
                       contrast 0x00980901 (int)    : min=0 max=255 step=1 default=32 value=32
                     saturation 0x00980902 (int)    : min=0 max=255 step=1 default=32 value=32
 white_balance_temperature_auto 0x0098090c (bool)   : default=1 value=1
                           gain 0x00980913 (int)    : min=0 max=255 step=1 default=64 value=65
           power_line_frequency 0x00980918 (menu)   : min=0 max=2 default=2 value=2
      white_balance_temperature 0x0098091a (int)    : min=2800 max=6500 step=1 default=4000 value=3320 flags=inactive
                      sharpness 0x0098091b (int)    : min=0 max=255 step=1 default=22 value=22
         backlight_compensation 0x0098091c (int)    : min=0 max=1 step=1 default=1 value=1
                  exposure_auto 0x009a0901 (menu)   : min=0 max=3 default=3 value=3
              exposure_absolute 0x009a0902 (int)    : min=3 max=2047 step=1 default=166 value=415 flags=inactive
         exposure_auto_priority 0x009a0903 (bool)   : default=0 value=1
                   pan_absolute 0x009a0908 (int)    : min=-36000 max=36000 step=3600 default=0 value=0
                  tilt_absolute 0x009a0909 (int)    : min=-36000 max=36000 step=3600 default=0 value=0
                 focus_absolute 0x009a090a (int)    : min=0 max=255 step=17 default=51 value=85 flags=inactive
                     focus_auto 0x009a090c (bool)   : default=1 value=1
                  zoom_absolute 0x009a090d (int)    : min=1 max=5 step=1 default=1 value=1

For example, to disable the auto focus and adjust it manually, run the following commands:

v4l2-ctl -c focus_auto=0
v4l2-ctl -c focus_absolute=$((17 * 6))

Creating a systemd service for the webstream

I typically find it more convenient to manage services rather than launch/stop scripts manually. There are some convient features of systemd, such as being able to automatically launch a service at boot, as well as restart services after an error occurs.

We'll start by making a convient launcher script under mjpg-streamer/mjpg-streamer-experimental/launch_webcam.sh:

#!/bin/bash

scriptDir=$(dirname -- "$(readlink -f -- "$BASH_SOURCE")")


cd "$scriptDir"
export LD_LIBRARY_PATH=.
./mjpg_streamer -o 'output_http.so -l 0.0.0.0 -p 8083' -i 'input_uvc.so -f 15 -r 640x480'

make it executable:

chmod +x launch-webcam.sh

Next, we'll create a new file for our camera service: /etc/systemd/system/camera-stream.service

[Unit]
Description=Webcam Steam using mjpg-streamer
After=network.target
StartLimitIntervalSec=0
[Service]
Type=simple
Restart=always
RestartSec=10
User=pi
ExecStart=/home/pi/mjpg-streamer/mjpg-streamer-experimental/launch_webcam.sh

[Install]
WantedBy=multi-user.target

Reload the systemctl deamon so that it picks upu the new service file:

systemctl daemon-reload

Next, launch the service by running:

systemctl start camera-stream

Verify that the camera is working by running

systemctl status camera-stream.service

If you want the camera service to automatically start on boot, run:

systemctl enable camera-stream.service

Once the pi finishes rebooting, visit http://<HOSTNAME_OR_IP>:8083/?action=stream and the camera should be streaming 👍