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README.md

Device Shadow Controller Script for IoT-Bed

This script connects to the AWS IoT device shadow via MQTT and sends BLE commands using gatttool to resolve deltas in the device shadow.

Overview

Features:

  • Bed position presets: Zero-G, Flat, TV/PC
  • Massage setting: head and foot 4 levels on and off.

See the BLE Control guide for details on the BLE protocol.

Sometimes the gatttool commands error out so the script tries to send the commands up to 3 times before giving up.

Faking the Massage 'off' command

Since the massage setting is a single action button to increase massage level, there is no "off" command. The operator has to cycle through all of the massage levels before it turns off.

The state of massage is stored as an integer between 0 and 100 that increments by 25 whenever the massage on lambda action is fired.

To simulate the "off" command, the Lambda function takes the current value of the massage level, for example 50 and makes it negative, -50, the shadow controller script sees that the change is less than 0 so it computes the number of massage levels needed to get back to 0 and sends that many commands in sequence.

num_cmds = int((100 - abs(massagePercent)) / 25)

Implementing custom head and foot adjustment angles

Since there is no way to directly command a head or foot angle, adding the ability to control the angle is going to be tricky.

Running with systemd

Install the dependencies:

pip install -U AWSIoTPythonSDK

Copy the certs and root CA to the same directory as the script before running.

  • device.pem: IoT certificate
  • device-key.pem: IoT private key
  • root-CA.crt: root CA for certificate.

See the IoT Device guide for how to create the thing and certs.

Export the environment variables:

export IOT_ENDPOINT=$(aws iot describe-endpoint | jq -r '.endpointAddress')
export THING_NAME=iot-bed
export BLE_ADDRESS=ADDRESS_OF_BLE_BASE

Run the script:

python iot-bed.py

Installing as a systemd service

Install script and certs to /opt/iot-bed and run as a systemd service:

cat > iot-bed.service <<"EOF"
[Unit]
Description=IoT Bed Controller
Wants=network-online.target
After=network-online.target

[Service]
Restart=always
TimeoutStartSec=0
RestartSec=3
Environment=IOT_ENDPOINT=YOUR_IOT_ENDPOINT
Environment=THING_NAME=iot-bed
Environment=BLE_ADDRESS=ADDRESS_OF_BLE_BASE
WorkingDirectory=/opt/iot-bed
ExecStartPre=/bin/bash -c 'until /usr/bin/curl -sf -o /dev/null http://status.aws.amazon.com/data.json; do echo "Waiting for network.."; sleep 5; done'
ExecStart=/usr/bin/python /opt/iot-bed/iot-bed.py

[Install]
WantedBy=multi-user.target
EOF

sed -i \
  -e s/YOUR_IOT_ENDPOINT/$IOT_ENDPOINT/g \
  -e s/ADDRESS_OF_BLE_BASE/$BLE_ADDRESS/g \
  iot-bed.service

sudo mv iot-bed.service /etc/systemd/system/

sudo systemctl daemon-reload
sudo systemctl enable iot-bed
sudo systemctl start iot-bed

sudo systemctl status iot-bed --no-pager

Remember to copy the certs device* and root CA root-CA.crt to /opt/iot-bed/ before starting.

Installing and running with Docker

or with docker-compose on HypriotOS with RPI3

Install HypriotOS on your Raspberry Pi 3

git clone https://github.com/danisla/iot-bed.git

Copy your device-key.pem device.pem device.pub and root-CA.crt to the src/iot/ directory.

cd iot-bed/src/iot
cat > .env <<"EOF"
IOT_ENDPOINT=YOUR IOT ENDPOINT
THING_NAME=iot-bed
BLE_ADDRESS=YOUR BLE ADDRESS
EOF

docker-compose pull
docker-compose up -d

References