About

This project features a privacy-friendly baby monitor (video only) for the enthusiast.

Basis for it is a Raspberry Pi Zero with a camera
Embedded within a custom-created case
Only sends data in local network
Accessible with any device (only web browser is required)
Manual control of IR LEDs to illuminate picture in dark conditions

We use this thing on a day-to-day base, it is mounted above our daughter's bed. If the power supply and cable is good, it runs very stable for weeks.

Hardware

The components are pretty standard:

A Raspberry Pi Zero W plus a suitable SD card
A Camera for the Pi (tested with th standard one)
An extra break-out-board supplying and holding the IR LEDs

The IR board

The schematic can be seen below: The Pi's GPIOs don't provide enough current to drive the LEDs, so a ULN2003 is used to amplify.

You can craft a PCB on your own, I just soldered it to a Lochrasterplatine.

Casing

The files are uploaded as FreeCAD model and the STL export. It looks like this: The rectangular hole is the outlet for the 4 IR LEDs, the round hole is for the camera.

This casing is custom-created for her bed, you may need to modify it to properly mount it. You're welcome to reuse parts of the freecad design.

Software setup

The software is based on '''Raspberry Pi OS''', so get it from https://www.raspberrypi.org/software/.

Preparing SD card

Write the Raspberry Pi OS image to the SD card, whichever way you prefer (I use dd)
Create an empty file named ssh on the boot partition.
Create a file wpa_supplicant.conf on the boot partition, with the following content:

ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1
country=DE

network={
    ssid="<your WLAN's SSID>"
    psk="<the WLAN's password>"
    key_mgmt=WPA-PSK
}

The "network" section can be duplicated to be capable to connect in multiple places.

Booting up and basic setup

Now insert this SD card into the Pi and boot it up. Follow these steps after boot.

Connect to the Pi via ssh: ssh pi@raspberrypi (maybe you need to look up the Pi's IP address in your router ...)
- password is raspberry
Edit /etc/hostname to contain whatever name you want to reach your cam at (for me this is lonicam)
Run sudo raspi-config
- Set your personal password
- Enable camera interface
- Extend primary partition to whole SD card
- Set the correct timezone
Reboot, reconnect ssh
Run apt update and apt dist-upgrade
Reboot, reconnect ssh
Run apt install vim wiringpi git (hint: starting with Bullseye release wiringpi is no longer available, so omit it there)

Installing camera service

Now download the RPi Cam Control project with git clone https://github.com/silvanmelchior/RPi_Cam_Web_Interface.git LoniCAM. After that cd into the LoniCAM folder. Run sudo ./install.sh. The web server is best case lighttpd (low on resources, and fully sufficient).

The installation process will take quite some time. Allow it to start the camera and then you will already be able to connect to the service.

IR LED control

The IR LEDs are connected to the Pi's GPIO_12 pin, which is PWM capable. Thus the LED brightness can be controlled.

Raspberry Pi OS

The PWM can be controlled directly via sysfs interface. Therefore PWM clock sources must be enabled in the overlay, so add this line to the /boot/config.txt:

dtoverlay=pwm

To enable extra buttons in the web UI to control the LED, create the script /var/www/html/macros/ledsOn.sh with this:

#!/bin/bash

echo 1000000 > /sys/class/pwm/pwmchip0/pwm0/period
echo 500000 > /sys/class/pwm/pwmchip0/pwm0/duty_cycle
echo 1 > /sys/class/pwm/pwmchip0/pwm0/enable

The ratio of the values 500000 / 1000000 defines the duty cycle of the signal and hence the brightness, so it is set to 50% with this config.

Create the script cat /var/www/html/macros/ledsOff.sh with this content:

#!/bin/bash

if [ -e /sys/class/pwm/pwmchip0/pwm0/enable ]
then
	echo 0 > /sys/class/pwm/pwmchip0/pwm0/enable
fi

Set both scripts executable.

Create a script /opt/enablePWMForAll.sh with this content:

# create the pwm control structures, if needed
if [ ! -e /sys/class/pwm/pwmchip0/pwm0 ]
then
	echo 0 > /sys/class/pwm/pwmchip0/export
	
	chmod a+w /sys/class/pwm/pwmchip0/pwm0/enable
	chmod a+w /sys/class/pwm/pwmchip0/pwm0/duty_cycle
	chmod a+w /sys/class/pwm/pwmchip0/pwm0/period
fi

Make it executable and add the line sudo /opt/enablePWMForAll.sh to the file /etc/rc.local.

Raspberry Pi OS before Bullseye

The package wiringpi got deprecated in the newest version of Raspberry Pi OS (which is based on Bullseye), hence this will only work in older version until Buster.

To enable extra buttons in the web UI to control the LED, create the script /var/www/html/macros/ledsOn.sh with this:

#!/bin/bash
gpio -g mode 12 pwm
gpio -g pwm 12 350

The value of 350 defines the brightness. 1024 means duty cycle of 100%. Adjust to your personal needs.

Create the script cat /var/www/html/macros/ledsOff.sh with this content:

#!/bin/bash
gpio -g mode 12 pwm
gpio -g pwm 12 0

Set both scripts executable.

Configuration of server

Create the file /var/www/html/userbuttons with this content:

LICHT AN,ledsOn.sh,btn btn-success btn-lg,style="width:50%" autofocus
LICHT AUS,ledsOff.sh,btn btn-danger btn-lg,style="width:50%"

The next restart of the PI (or the web server) you will be greeted with 2 extra buttons to control the IR LEDs.

Disable the Pi's green LED

Otherwise it is rather disturbing for the child. Add this line to /etc/rc.local file:

echo kbd-altgrlock > /sys/class/leds/led0/trigger

Since no keyboard is attached, this will do the trick, and the LED is permanently off. Oddly enough none did not work as expected.

Auto-disable the IR LEDs based on timer

This is a lazy workaround. Better it would be to program a timer to automatically disable after 60 seconds or so. Run crontab -e and add this line:

*/5 * * * * (gpio -g pwm 12 0)

This will disable the IR LEDs automatically every 5 minutes. Just to ensure they don't permanently lit up.

Enable the Pi's Watchdog

Basically it is beneficial to set up the Pi's watchdog ... sometimes it occured to me that it got stuck or hung (maybe due to power struggles). The watchdog will bring it back to life again.

Install the watchdog with sudo apt install watchdog. Edit the file /etc/watchdog.conf and enable the following lines:

watchdog-device        = /dev/watchdog
max-load-1             = 24

Get Rid of Recording/Timelapsing Buttons

Find the div by the id main-buttons in the file /var/www/html/index.php and comment the whole element out (all 7 rows). It reduces the GUI so you don't see the unused and confusing buttons no more.

Check SD card

Especially when shut down by just disconnecting the power, the SD card and the filesystems can be corrupted. This checks for bad blocks:

> sudo badblocks -n -v -s /dev/mmcblk0

This scans the file system:

> sudo e2fsck -f /dev/mmcblk0p2