Fixes #4 Add PIR sensor

README.md

@@ -47,3 +47,17 @@ use the default user "pi" to run the calendar, and this user has sudo permission
 17. `reboot` the pi
 18. Log in to your Google account on the Pi
 19. Put a bow on it. You're done!
+
+## Adding a passive infra-red sensor
+1. Get an HC-SR501 sensor module.  Set its L/H option to "H", either with a jumper or a dot of solder.
+2. Connect wires to pins 4, 6, and 16 on the top row of connectors. With the connector at the top left of the board,
+the top leftmost pin is #2, and the top row is numbered by twos (the bottom row gets the ones). Pin 16 is GPIO 23.  
+If you change the scripts, you can change the pin.  
+3. With the HC-SR501 pins at the top and facing you, the leftmost pin is ground.  Connect that to the wire from pin 6 on the Pi.
+4. Connect the rightmost pin on the HC-SR501 to pin 4 from the Pi.
+5. Connect the center pin on the HC-SR501 to pin 16 from the Pi.
+6. Mount the HC-SR501 to your monitor, but away from the power LED or anything else that might mess with detection.
+7. When you run the playbook (either by `ansible-playbook` or `calendar-install.run`), add a parameter 'DPMS_TIMEOUT_MIN=20'.
+(Set it to your favorite value.  I like 20 minutes.)  For `ansible-playbook` execution, you'll want to prefix that with `--extra-vars `
+8. The playbook installs a `pir-monitor` systemd service that wakes the display when motion is detected. Set `CEC_FALLBACK=true` if your monitor needs HDMI‑CEC to wake up. The service starts automatically on boot and can be checked with `systemctl status pir-monitor`.
+9. Watch it go

install.sh

@@ -26,4 +26,7 @@ grep -q localhost $kh || ssh-keyscan localhost >>$kh
 # install Ansible if necessary
 sudo dpkg -s ansible 2>&1 >/dev/null || sudo apt-get install -y ansible
 
-ansible-playbook playbook.yml -i hosts-localhost -u pi
+if [ $# -gt 0 ]; then
+    EXTRA_VARS="--extra-vars $*"
+fi
+ansible-playbook playbook.yml -i hosts-localhost -u pi $EXTRA_VARS

release_number.txt

@@ -1 +1 @@
-1
+2

roles/calendar/files/pir-monitor.service.j2

@@ -0,0 +1,15 @@
+[Unit]
+Description=PIR sensor monitor to wake display on motion
+After=graphical.target
+
+[Service]
+Type=simple
+User=pi
+Group=pi
+ExecStart=/usr/local/bin/pirMonitor
+Environment=DISPLAY=:0.0
+Environment=CEC_FALLBACK={{ '1' if CEC_FALLBACK | bool else '0' }}
+Restart=always
+
+[Install]
+WantedBy=graphical.target

roles/calendar/files/pirMonitor

@@ -0,0 +1,93 @@
+#!/usr/bin/env python3
+
+"""Monitor a PIR sensor and wake the display when motion is detected."""
+
+import argparse
+import logging
+import os
+import shutil
+import subprocess
+import time
+
+import RPi.GPIO as GPIO
+
+
+def display_is_on() -> bool:
+    """Return True if the monitor appears to be on."""
+    try:
+        out = subprocess.check_output(["xset", "-q"], text=True, stderr=subprocess.DEVNULL)
+    except (FileNotFoundError, subprocess.CalledProcessError):
+        return True  # Assume on if we cannot determine
+    for line in out.splitlines():
+        if "Monitor is" in line:
+            return "On" in line
+    return True
+
+
+def wake_display(use_cec: bool) -> None:
+    """Wake the display using DPMS and optionally HDMI-CEC."""
+    if os.getenv("XDG_SESSION_TYPE") == "wayland":
+        cmd = ["loginctl", "unlock-sessions"]
+    else:
+        cmd = ["xset", "dpms", "force", "on"]
+    subprocess.run(cmd, check=False)
+    time.sleep(2)
+    if use_cec and not display_is_on():
+        logging.info("Falling back to HDMI-CEC")
+        if shutil.which("cec-client"):
+            try:
+                subprocess.run(
+                    ["cec-client", "-s", "-d", "1"],
+                    input="on 0\n",
+                    text=True,
+                    check=False,
+                )
+            except Exception as exc:  # pragma: no cover - best effort
+                logging.debug("CEC command failed: %s", exc)
+        else:
+            logging.debug("cec-client not installed")
+
+
+def main() -> None:
+    parser = argparse.ArgumentParser(description="PIR motion monitor")
+    parser.add_argument("--pin", type=int, default=23, help="GPIO pin number")
+    parser.add_argument(
+        "--idle",
+        type=int,
+        default=30,
+        help="minimum seconds between wake commands",
+    )
+    parser.add_argument("--display", default=":0.0", help="display for xset")
+    parser.add_argument(
+        "--cec-fallback",
+        action="store_true",
+        default=os.getenv("CEC_FALLBACK", "0") in ("1", "true", "True"),
+        help="use HDMI-CEC if DPMS fails",
+    )
+    args = parser.parse_args()
+
+    os.environ["DISPLAY"] = args.display
+    logging.basicConfig(level=logging.INFO, format="%(asctime)s %(message)s")
+
+    GPIO.setmode(GPIO.BCM)
+    GPIO.setwarnings(False)
+    GPIO.setup(args.pin, GPIO.IN)
+
+    last_trigger = 0.0
+    logging.info("Monitoring GPIO pin %s", args.pin)
+    try:
+        while True:
+            GPIO.wait_for_edge(args.pin, GPIO.RISING)
+            now = time.time()
+            if now - last_trigger >= args.idle:
+                logging.info("Motion detected")
+                wake_display(args.cec_fallback)
+                last_trigger = now
+    except KeyboardInterrupt:
+        pass
+    finally:
+        GPIO.cleanup()
+
+
+if __name__ == "__main__":
+    main()

roles/calendar/files/startup.sh

@@ -4,4 +4,6 @@
 # [ $(lsusb | wc -l) -lt 4 ] && echo '1-1' | sudo tee /sys/bus/usb/drivers/usb/unbind
 
 # Start the browser
-chromium-browser --app=https://calendar.google.com/calendar/r/custom/7/d --user-agent="Mozilla/5.0 (Windows; U; Windows NT 6.1; rv:2.2) Gecko/20110201" --disable-infobars --disable-session-crashed-bubble --kiosk &
+nohup chromium-browser --app=https://calendar.google.com/calendar/r/custom/7/d --user-agent="Mozilla/5.0 (Windows; U; Windows NT 6.1; rv:2.2) Gecko/20110201" --disable-infobars --disable-session-crashed-bubble --kiosk </dev/null 2>&1 >/dev/null  &
+
+# The pir-monitor systemd service handles keeping the display awake when blanking is enabled

roles/calendar/tasks/main.yml

@@ -1,3 +1,12 @@
+- name: Fetch Raspberry pi model
+  slurp:
+    src: "/sys/firmware/devicetree/base/model"
+  register: rpi_model_data
+
+- name: Set Raspberry Pi model
+  ansible.builtin.set_fact:
+     rpi_model: "{{ rpi_model_data['content'] | b64decode }}"
+
 - name: Install Chromium
   package: 
       name: chromium-browser
@@ -8,12 +17,12 @@
       name: scrot
       state: latest
 
-- name: Install feh
+- name: Install feh to display an image
   package:
       name: feh
       state: latest
 
-- name: Install wmctrl
+- name: Install wmctrl to control windows
   package:
       name: wmctrl
       state: latest
@@ -23,12 +32,18 @@
       name: unclutter
       state: latest
 
+- name: Install cec-utils for HDMI-CEC control
+  package:
+      name: cec-utils
+      state: latest
+  when: CEC_FALLBACK | bool
+
 - name: Install python-uinput to fake keystrokes in the browser
   pip: 
      executable: /usr/bin/pip3
      name: python-uinput
 
-- name: Load the uinput module so we can fake keystrokes
+- name: Load the uinput module to fake keystrokes
   lineinfile:
      dest: /etc/modules
      create: true
@@ -48,7 +63,7 @@
      mode: '0755'
      owner: pi
 
-- name: Install refresh_cal script
+- name: Install refresh_cal script to scroll to the right spot on the calendar periodically
   copy:
      src: refresh_cal
      dest: /home/pi/refresh_cal
@@ -75,7 +90,7 @@
     job: "/home/pi/refresh_cal"
   when: false
 
-- name: Autostart folder 
+- name: Autostart folder for LXDE
   file:
     path: "/home/pi/.config/autostart"
     state: directory
@@ -89,19 +104,50 @@
      mode: '0644'
      owner: pi
 
-- name: Remove default screensaver config
+- name: Remove default graphical screensaver config
   lineinfile:
      dest: /etc/xdg/lxsession/LXDE-pi/autostart
      state: absent
      line: "@xscreensaver -no-splash"
 
 - name: Turn off screensaver in LXDE autostart
-  blockinfile:
+  template:
+     src: autostart-no-screensaver
      dest: /etc/xdg/lxsession/LXDE-pi/autostart
-     create: true
+     mode: '0644'
+     owner: pi
+     group: root
+  when: ( DPMS_TIMEOUT_MIN | int ) <= 0
+
+- name: Copy the script to monitor PIR sensor
+  copy:
+     src: pirMonitor
+     dest: /usr/local/bin/pirMonitor
+     mode: '0755'
+     owner: root
+     group: root
+  when: ( DPMS_TIMEOUT_MIN | int ) > 0
+
+- name: Install systemd service for PIR monitor
+  template:
+     src: pir-monitor.service.j2
+     dest: /etc/systemd/system/pir-monitor.service
+     mode: '0644'
+  when: ( DPMS_TIMEOUT_MIN | int ) > 0
+
+- name: Enable and start pir-monitor service
+  systemd:
+     name: pir-monitor.service
+     enabled: yes
+     state: started
+     daemon_reload: yes
+  when: ( DPMS_TIMEOUT_MIN | int ) > 0
+
+- name: Turn on screensaver in LXDE autostart
+  template:
+     src: autostart-with-DPMS
+     dest: /etc/xdg/lxsession/LXDE-pi/autostart
+     mode: '0644'
      owner: pi
-     block: |
-        @xset s noblank
-        @xset s off
-        @xset s -dpms
-# for Pi 4, the last line should be "@xset dpms 0 0 0", but I haven't figured out how to detect the Pi 4 yet.
+     group: root
+  when: ( DPMS_TIMEOUT_MIN | int ) > 0

roles/calendar/templates/autostart-no-screensaver

@@ -0,0 +1,6 @@
+@lxpanel --profile LXDE-pi
+@pcmanfm --desktop --profile LXDE-pi
+point-rpi
+@xset s noblank
+@xset s off
+@xset s {% if rpi_model.startswith("Raspberry Pi 4") %}dpms 0 0 0{% else %}-dpms{% endif %}

roles/calendar/templates/autostart-with-DPMS

@@ -0,0 +1,6 @@
+@lxpanel --profile LXDE-pi
+@pcmanfm --desktop --profile LXDE-pi
+point-rpi
+@xset s blank
+@xset s dpms
+@xset s {{ ( DPMS_TIMEOUT_MIN | int ) * 60 }} {{ ( DPMS_TIMEOUT_MIN | int ) * 60 }}

roles/calendar/vars/main.yml

@@ -0,0 +1,6 @@
+---
+# Screensaver timeout in minutes - 0 means no timeout
+# Configure a PIR sensor to show the display when necessary
+DPMS_TIMEOUT_MIN: 0
+# Enable HDMI-CEC fallback if DPMS does not wake the display
+CEC_FALLBACK: false