Pilarm

Raspberry Pi alarm clock

Step one, for childs: the idea was to have a simple device that let my child know whether he can wake up or should stay in bed without a light always on, which is the case of all child alarm clock for sell. In action, it's pretty simple: a sonar listen for moves, when a move is detected, if the child should stay in bed, a (blue) led is turned on for 2 seconds, when he can wake up, another led (green) is turned on. Everyhting else is bonus (screen, animation).

To make the alarm clock work even when not connected to wifi, we have to add an RTC clock: Raspberry Pi doesn't bring RTC, so time is fetched using network by default.

Hardware

• Raspberry Pi/Pi Zero W
• Sonar:
  • HC-SR04
• LEDs (optional):
  • two leds with different colors or one rgb led
  • 220Ω resistor by led
• Screen (optional):
  • 0.96" oled screen SSD1306
  • 1kΩ resistor for the screen
• RTC (optional):
  • DS3231/DS1307

RTC and screen

RTC and screen are both using I2C. By default Raspberry Pi have only i2c bus, to use both RTC and screen, you'll need to create an I2C bus, convert GPIO ports to SDA/SCL. Edit the /config/boot.txt file and add the following line :

dtoverlay=i2c-gpio,bus=4,i2c_gpio_delay_us=1,i2c_gpio_sda=24,i2c_gpio_scl=23

This will create an I2C bus (#4), set GPIO23 as SCL and GPIO24 as SDA. I plugged RTC on this pins.

RTC DS3231 powerled

Once everyhting is setup and working, you can remove the RTC powerled using a flat screendriver.

Install OS

Use Raspberry Pi Imager to install the latest version of Raspbian Lite.

Before writing data on the SD card, press on SHIFT+CTRL+X to enter default options:

• set the hostname
• enable SSH
• configure wifi (remember that some Pi such as Zero does not support 5Ghz wifi)

Setup and start

If you need to configure your Pi (set timezone, GPIO configuration for RTC), do it before the following step.

pilarm runs on docker. After your OS fresh install, run the following script to install deps, configure the Pi and start the container. It will create a docker-compose.yaml file in home with the content of the sample given, and add a config.json file in home/pilarm with sample content, with screen detected.

wget https://raw.githubusercontent.com/pierrecle/pilarm/develop/setup.sh  -O - | bash

Update configuration

Edit the config.json file and run:

sudo docker-compose restart pilarm

Config file

{
    "debug": true,
    "leds": {
        "are_present": true,
        "can_wake_up_pin": 27, // BCM number
        "stay_in_bed_pin": 17, // BCM number
        "can_wake_up_display_duration": 2, // in seconds
        "stay_in_bed_display_duration": 1 // in seconds
    },
    "screen": {
        "is_present": true,
        "can_wake_up_animation_file": "pikachu.gif", // have to be un ressources folder
        "can_wake_up_animation_duration": 1.5, // in seconds
        "can_wake_up_display_time_duration": 5, // in seconds
        "stay_in_bed_display_time_duration": 2 // in seconds
    },
    "sonar": {
        "trigger_pin": 6, // BCM number
        "echo_pin": 13, // BCM number
        "min_distance": 0.03, // in meters
        "max_distance": 0.5 // in meters
    },
    "times": {
        "wake_up": {
            "monday": "07:30",
            "tuesday": "07:30",
            "wednesday": "08:30",
            "thursday": "07:30",
            "friday": "07:30",
            "saturday": "08:30",
            "sunday": "08:30"
        },
        "to_bed": "20:30"
    }
}

Development

On your Pi, install go:

sudo apt install golang

Then, edit files (with VSCode and Go add-on, everyhting is way easier) and run:

go run main.go

Build and run using docker

sudo docker build . -t pilarm_local -f Dockerfile
sudo docker run  --device /dev/i2c-1 --privileged --volume $PWD/data:/app/data --volume /usr/bin/aplay:/usr/bin/aplay --rm pilarm_local

Todo

• chore move pilarm.go somewhere else
• feat implement hcsr04 using periph.io
• feat clean up on quit
• feat track when sonar is triggered
• feat handle RTC DS3231
• feat turn RTC power led off
• feat handle DST (summer/winter time)
• feat make RTC optional
• feat make screen optional
• feat make leds optional
• feat remove hard coded values
  • times
  • pinning
  • sonar maximum distance
  • led display duration
  • screen display duration
  • animation
• feat display current time after animation when can wake up
• feat display current time when should stay in bed and make it optional
• feat play sound when wake up
• feat increase sound with time
• feat add sun animation using leds when wake up
• feat handle snooze
• feat make durations of sonar interruptions configurable
• doc make a video
• doc draw pinning
• doc write technical documentation
• hardware make a PCB
• hardware make a 3D printable basic case
• chore handle releases with workflow etc
• chore write update process when not using portainer
• feat create an OSD to display basic information (hostname, ip, wifi, current time)
• feat add a physical buttons to handle OSD
• feat create an API to change values
• BONUS handle HUE lights to wake up
• BONUS front-end app
• BONUS HASS/MQTT

Ressources

• Turn off leds on PI
• HCSR04 implementation with rpio