Wiring the Internet of Things
Geek Gathering #7 February 2015
After a short introduction into MQTT and Node-RED we will use an Arduino combined with an “IoT Shield” to prototype some IoT gadgets.
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MQTT is a machine-to-machine (M2M)/"Internet of Things" connectivity protocol. It was designed as an extremely lightweight publish/subscribe messaging transport. It is useful for connections with remote locations where a small code footprint is required and/or network bandwidth is at a premium.
publish/subscribe messaging
publish/subscribe messaging
publish/subscribe messaging
publish/subscribe messaging
topic
key that identifies the information channel to which payload data is published
hierarchy structure very much like the Filesystem Hierarchy
GG/Iot/1/Temperature
GG/Iot/1/Humidity
GG/Iot/1/Button/A
GG/Iot/1/Button/B
GG/Iot/2/Temperature
GG/Iot/2/Humidity
GG/Iot/2/Button/A
GG/Iot/2/Button/B
topic wildcards
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var client = new Paho.MQTT.Client(...);
client.subscribe("GG/SlideController/WiringIoT/Command");
client.onMessageArrived = function(message) {
switch(message.payloadString) {
case 'next' : deck.next(); break;
case 'prev' : deck.prev(); break;
}
};
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https://iotteam{{team.teamId}}.azurewebsites.net |
used services
- shiftr.io - really cool publish/subscribe communication infrastructure service used as MQTT Broker.
- Azure Websites - used to host the Node-RED instance.
used hardware
- Arduino Uno - base to build the geek gathering sensor nodes..
- Raspberry Pi - used as MQTT-SN gateway to map from the MQTT-SN senor network to the MQTT LAN/WAN.
- nRF24L01+ - the ultra low power 2.4GHz RF transceiver used for the sensor network.
used software
- Node-RED - visual tool for wiring the Internet of Things..
- Eclipse Paho JavaScript Client - is a browser-based library that uses WebSockets to connect to a MQTT.
code @
- Geek Gathering IoT Shield - Arduino Sketch and Eagle files for the PCB..
- BtMqttSn - Arduino library for an MQTT-SN client communicating over an nRF24L01+ transceiver.
- BtMqttSnGateway - A MQTT-SN gateway running on a Raspberry Pi communicating over a nRF24L01+ transceiver.
- This presentation - and online @ http://geekgathering.github.io/presentation-wiring-IoT.