A robust room presence solution for home automation with nearly no false negatives

Argos Room Presence

This project builds a room presence solution on top of Argos. Using just a cheap raspberry pi zero w (plus an attached pi camera, or an RTMP enabled camera] in any room, this project provides a reliable, robust and efficient mechanism to detect if people are present in that room or not, allowing you to then use it as an MQTT sensor in HomeAssistant for automating lighting, media players, heating or what have you in that room, as a consequence.

Preface

For a long time, I’ve been trying to figure out a robust room presence solution for my home automation setup within HomeAssistant. I’ve tried everything from integrating simple battery operated wifi-connected PIR motion sensors to bluetooth LE based detection using a cluster of raspberry pi zero’s running room-assistant. It all works half of the time and then crumbles down like a house of cards rest of the time. After a lot of tinkering and tuning, I have now devised a solution, which I can confidently proclaim, is completely devoid of any false positives or false negatives, and works reliably in the real world. And trust me, when it comes to room presence, what matters is false negatives! Folks absolutely hate you when your fancy home automation turned off the TV and all the lights when everyone was tuned into that game/movie!

So, whats the secret sauce?

argos-presence provides reliable room presence by using computer vision. Forget all the thermal imaging sensors, PIR motion sensors and bluetooth scanning solutions. Raspberry Pi’s can now run sophisticated computer vision algorithms and even machine learning algorithms (thank you tensorflow lite!) thanks to all the performance advancements in both single board computers and advancements in OpenCV and tensorflow.

Here’s how argos-presence works:

The executive summary is the following:

• Argos-presence is detecting movement (even the tiniest finger or facial movement), and then making sure the movement is actually a person when it matters.
• We dont simply set the presenceStatus based on motion. We have warmUp and coolDown periods.
• When motion tries to switch presenceStatus from on to off, we have a coolDown period where the argos object detection service is called to figure out if there’s a person in the scene, and we keep extending the cool down till a person is detected. This is to avoid false negatives
• When motion tries to switch presenceStatus from off to on, we have a warmUp period where, again we detect if a person is present or not. This is to avoid false positives. For example, if your presenceStatus recently went from on to off, your lights are in the process of turning off, which can be seen as motion by the detector. If we did not have a warmUp period, your room would keep flipping the lights on and off continuously. Note: this doesn’t mean you have to wait 30 seconds (warmUp seconds) for your lights to turn on. During warmup, it terminates the warmup and switches to presenceStatus ON immediately if a person is detected (and only if…). The warmUp period is only in effect after a recent change from presence to no presence (from last motion). The other times whenever you come into the room, argos will go into presence status immediately (with just motion). You can even turn off warmUp mode by setting warmUp seconds to 0.
• The warmup and cooldown periods need to be configured (sensible tried and tested defaults are already set in the example config) to accommodate for your environment.
• In effect, your lights (or whatever you choose to turn on in your automation) will turn ON instantly, but they’ll take coolDown seconds (e.g. 5 minutes) to turn off and will ONLY turn off when there’s no computer vision detected human in the frame (so no false negatives – a big principle on which the project was built)

Installation

Depending on the deployment model you chose, you may have to install argos on the same device as argos-presence or on a different device. Follow the instructions to install argos here. You still have to clone argos and make it available in the PYTHONPATH as argos-presence uses it’s motion detection API. This is done in the systemd service file provided.

On your pi:

cd ~
git clone https://github.com/angadsingh/argos-presence
sudo apt-get install python3-pip
pip3 install --upgrade pip
sudo apt-get install python3-venv
python3 -m venv argos-presence-venv/
source argos-presence-venv/bin/activate
pip install wheel
pip install -r argos-presence/requirements.txt

install it as a systemd service:

sudo cp argos-presence/resources/systemd/argos_presence.service /etc/systemd/system/
sudo systemctl daemon-reload
sudo systemctl enable argos_presence.service
sudo systemctl start argos_presence

see the logs

journalctl --unit argos_presence.service -f

As a docker container

You can use the following instructions to install argos-presence as a docker container.

Install docker (optional)

curl -fsSL https://get.docker.com -o get-docker.sh
sudo sh get-docker.sh

Run argos-presence as a docker container

Note: only docker images for armv7 (raspberry pi 2/3/4) and armv6 (raspberry pi zero/w) are provided. It should be trivial to support an amd64 dockerfile as well -armv6/v7 are much harder to figure out (contributions welcome!).

replace “armv7” with “armv6” in the below instructions for running on raspberry pi zero (/w)!

docker run --rm -p8000:8000 -v configs:/configs \
    -v /home/pi/motion_frames:/motion_frames angadsingh/argos-presence:arvmv7 \
    --config configs.your_config --camconfig configs.your_camconfig

make a systemd service to run it automatically. these services automatically download the latest docker image and run them for you:

sudo wget https://raw.githubusercontent.com/angadsingh/argos-presence/main/resources/systemd/argos_presence_docker.service -P /etc/systemd/system/
sudo systemctl daemon-reload
sudo systemctl enable argos_presence_docker.service
sudo systemctl start argos_presence_docker

see the logs

journalctl --unit argos_presence_docker.service -f

Usage

You can run Argos Room Presence in the following modes of deployment:

You can run room presence like this (although its best to run it as a systemd service as described in the installation section):

PYTHONPATH=$PYTHONPATH:/home/pi/argos presence.py --ip 0.0.0.0 --port 8000 --config config --camconfig camconfig

Just like argos, argos-presence also exposes:

• a flask server which serves a web page where you can see the motion and person detection happening in action
• an image and video feed for you to use as a camera in HA (more on that below)
• APIs to get current status, set config and even set PiCamera configuration dynamically

Home Assistant Integration

Once argos-presence is up and running, streaming your picamera or RTMP camera feed, doing motion detection, doing local or remote object detection by calling the argos service or API, and sending presence state to HA via MQTT, you can create an MQTT sensor and automation in HA to act on that presence state

Create the MQTT sensor:

sensor:
  - platform: mqtt
    name: "Argos Room Presence Sensor Living Room"
    state_topic: "home-assistant/argos-room-presence/living_room"
    unit_of_measurement: "presence"

a sample automation which turns on/off a scene in a room based on presence:

alias: Living Room Presence Based Scene Activation
description: ''
trigger:
  - platform: state
    entity_id: sensor.argos_room_presence_sensor_living_room
    to: '1'
    from: '0'
  - platform: state
    entity_id: sensor.argos_room_presence_sensor_living_room
    from: '1'
    to: '0'
condition: []
action:
  - choose:
      - conditions:
          - condition: state
            entity_id: sensor.argos_room_presence_sensor_living_room
            state: '1'
        sequence:
          - scene: scene.living_room_on_scene
      - conditions:
          - condition: state
            entity_id: sensor.argos_room_presence_sensor_living_room
            state: '0'
        sequence:
          - scene: scene.living_room_off_scene
    default: []
mode: restart

one thing that we need to take care of is to accomodate for lighting changes during the day. argos-presence exposes a /camconfig API which lets you change any PiCamera property dynamically. We’ll use this API to change the camera settings for day and night lighting changes. This is necessary, as otherwise argus won’t be able to detect motion when the lights are off at night, for example. The below automation changes the exposure settings for the PiCamera at night such that it can see in low light as well! (you’ll be surprised how well that $8 camera sees in low light with the right settings!)

alias: Apply Argos Presence Dynamic Camera Settings
description: ''
trigger:
  - platform: time
    at: '17:30'
  - platform: time
    at: '06:30'
  - platform: homeassistant
    event: start
condition: []
action:
  - choose:
      - conditions:
          - condition: time
            after: '17:30'
            before: '06:30'
        sequence:
          - service: rest_command.argos_living_room_sensor_set_camconfig
            data:
              exposure_mode: 'off'
              framerate: 2
              iso: 0
              image_denoise: ''
              video_denoise: ''
              video_stabilization: ''
              shutter_speed: 499829
              meter_mode: spot
              exposure_compensation: 0
              awb_mode: 'off'
              awb_gains_red: 1.5625
              awb_gains_blue: 1.20703125
      - conditions:
          - condition: time
            after: '06:30'
            before: '17:30'
        sequence:
          - service: rest_command.argos_living_room_sensor_set_camconfig
            data:
              exposure_mode: auto
              framerate: 5
              iso: 0
              image_denoise: 1
              video_denoise: 1
              video_stabilization: ''
              shutter_speed: 0
              meter_mode: average
              exposure_compensation: 0
              awb_mode: auto
              awb_gains_red: 1
              awb_gains_blue: 1
    default: []
mode: single

for the above to work, we need to create some REST commands:

rest_command:
  argos_living_room_sensor_reset_bg:
    url: 'http://<argos-presence-host>:8000/config?reset_bg_model=True'
    timeout: 120
  argos_living_room_sensor_set_config:
    url: "http://<argos-presence-host>:8000/config?bg_accum_weight={{ states('input_text.argos_presence_sensor_background_accumulation_weight') }}&min_cont_area={{ states('input_text.argos_presence_sensor_minimum_contour_area') }}&tval={{ states('input_text.argos_presence_sensor_tval') }}&video_feed_fps={{ states('input_text.argos_presence_sensor_video_feed_fps') }}&presence_cooldown_secs={{ states('input_text.argos_presence_sensor_presence_cooldown_secs') }}&presence_warmup_secs={{ states('input_text.argos_presence_sensor_presence_warmup_secs') }}&argos_person_detection_enabled={{ states('input_text.argos_presence_sensor_person_detection_enabled') }}&argos_detection_threshold={{ states('input_text.argos_presence_sensor_person_detection_threshold') }}&argos_detection_frequency_frames={{ states('input_text.argos_presence_sensor_person_detection_frequency_frames') }}"
    timeout: 120
  argos_living_room_sensor_set_camconfig:
    url: "http://<argos-presence-host>:8000/camconfig?exposure_mode={{exposure_mode}}&framerate={{framerate}}&iso={{iso}}&image_denoise={{image_denoise}}&video_denoise={{video_denoise}}&video_stabilization={{video_stabilization}}&shutter_speed={{shutter_speed}}&meter_mode={{meter_mode}}&exposure_compensation={{exposure_compensation}}&awb_mode={{awb_mode}}&awb_gains_red={{awb_gains_red}}&awb_gains_blue={{awb_gains_blue}}"
    timeout: 120

you can create a lovelace tab for managing argos configuration from HA itself. first create some input helpers to take in text input for the properties you want to be able to change from the UI and then use the following lovelace card. this uses the REST command created above for the /config API (not /camconfig):

type: vertical-stack
cards:
  - type: entities
    entities:
      - entity: input_text.argos_presence_sensor_background_accumulation_weight
        name: Background Accumulation Weight
      - entity: input_text.argos_presence_sensor_tval
        name: Threshold tval
      - entity: input_text.argos_presence_sensor_minimum_contour_area
        name: Minimum Contour Area
      - entity: input_text.argos_presence_sensor_video_feed_fps
        name: Video Feed FPS
      - entity: input_text.argos_presence_sensor_presence_cooldown_secs
        name: Presence Cool Down Seconds
      - entity: input_text.argos_presence_sensor_presence_warmup_secs
        name: Presence Warm Up Seconds
  - type: button
    tap_action:
      action: call-service
      service: rest_command.argos_living_room_sensor_set_config
    name: Set config

it will look like this:

lastly, you can add the argo-presence video feed as a camera in home assistant! doing this you can then use a lovelace picture glance card to see your presence detector (doing motion detector and tensorflow based person detection) in action, and even record it’s footage using motionEye, etc.

camera:
- platform: mjpeg
    name: "Argos Living Room Presence Cam"
    still_image_url: "http://<argos-presence-host>:8000/image"
    mjpeg_url: "http://<argos-presence-host>:8000/video_feed"

add it to Lovelace:

aspect_ratio: 0%
camera_image: camera.argos_living_room_cam
entities:
  - entity: camera.argos_living_room_cam
title: Living Room Presence Cam
type: picture-glance

here’s how my presence tab looks like in lovelace:

Privacy

If you have privacy concerns about your presence camera video/image feed entering the network (and an attacker potentially getting access to it), then you can set the following config settings to completely disable the output frame

self.output_frame_enabled = False

You may also want to install the argos object detector locally.

GitHub

https://github.com/angadsingh/argos-presence