Demo Stop The Crazy Train - Lego Train Controller

Description

This demo is a part of global demo "Stop The Crazy train" : “ The train is running mad at full speed and has no driver ! Your mission, should you choose to accept it, is to train and deploy an AI model at the edge to stop the train before it crashes. This message will self-destruct in five seconds. Four. three. Two. one. tam tam tada tum tum tada tum tum tada tum tum tada tiduduuuuummmm tiduduuuuuuuuummm ”

Objectives

Showcase a nodejs application that control a Lego Train Ref : 60337 using Bluetooth, all commands are read from mqtt broker.

The controller can :

• discover the hub
• start and stop the train
• increase/decrase speed

Prerequisites

You will need:

• Podman
• Nodejs v20.7.0
• MQTT broker (mosquitto docker image)
• MQTT cli (mosquitto)

Local installation

On linux

sudo dnf install -y podman
sudo mkdir -p /tmp/mosquitto/{config,data,log}
sudo tee /tmp/mosquitto/config/mosquitto.conf <<EOF
persistence true
persistence_location /mosquitto/data/
listener 1883 0.0.0.0
protocol mqtt
allow_anonymous true
log_dest file /mosquitto/log/mosquitto.log
EOF
sudo dnf install -y mosquitto

On macos

mkdir -p /tmp/mosquitto/{config,data,log}
tee /tmp/mosquitto/config/mosquitto.conf <<EOF
persistence true
persistence_location /mosquitto/data/
listener 1883 0.0.0.0
protocol mqtt
allow_anonymous true
log_dest file /mosquitto/log/mosquitto.log
EOF
brew install mosquitto

Install package dependencies nodejs.

npm install

Test

Run the mqtt broker on linux.

sudo podman run -d --rm --name mosquitto -p 1883:1883 -p 9001:9001 -v /tmp/mosquitto/config:/mosquitto/config:z -v /tmp/mosquitto/data:/mosquitto/data:z -v /tmp/mosquitto/log:/mosquitto/log:z docker.io/library/eclipse-mosquitto:2.0.18

Run the mqtt broker on macos.

podman run -d --rm --name mosquitto -p 1883:1883 -p 9001:9001 -v /Users/mouchan/projects/mosquitto/config:/mosquitto/config -v /Users/mouchan/projects/mosquitto/data:/mosquitto/data -v /Users/mouchan/projects/mosquitto/log:/mosquitto/log docker.io/library/eclipse-mosquitto:2.0.18

On linux, you have to configure DBUS:

cat > /etc/dbus-1/system.d/node-ble.conf <<EOF
<busconfig>
  <policy user="$(id -un)">
   <allow own="org.bluez"/>
    <allow send_destination="org.bluez"/>
    <allow send_interface="org.bluez.GattCharacteristic1"/>
    <allow send_interface="org.bluez.GattDescriptor1"/>
    <allow send_interface="org.freedesktop.DBus.ObjectManager"/>
    <allow send_interface="org.freedesktop.DBus.Properties"/>
  </policy>
</busconfig>
EOF

Run the controller.

export NOBLE_USE_BLUEZ_WITH_DBUS=true
export DEBUG="bluez-dbus-bindings,poweredup,technicmediumhub,basehub"
node ./index.js

You should see something like this.

Connecting to MQTT broker mqtt://localhost:1883...
Scanning for Lego PoweredUp Hubs...
Connected to MQTT broker mqtt://localhost:1883!
Subscribed to topic train-command!
Connected to Lego Hub!
All hardware pieces have been discovered!
Lego City Train #60337 reached max speed!

Send all MQTT commands sequentially.

for cmd in `seq 0 1`; do mosquitto_pub -h localhost -p 1883 -t train-command -m "$cmd"; sleep 10; done

On the train-controller logs, you should see something like this.

Received message on MQTT topic train-command: 0
Handling SpeedLimit_30...
Processed command 0!
Received message on MQTT topic train-command: 1
Handling DangerAhead...
Processed command 1!

Available commands

0: "SpeedLimit_30",
1: "DangerAhead",

Enabling the Mock

If you do not have a proper Lego Hub, you can mock it.

export LEGO_BACKEND=mock
export DEBUG="lego-gear-mock"
node ./index.js