Node-Red IoT4School 2.0

The development of an exemplary Internet of Things infrastructure for use in computer science classes. For further information: https://doi.org/10.1145/3341525.3393987

Disclaimer

Version 2.0 breaks previous versions. It is strongly advised not to upgrade, if you're using an old version of iot4school.

I can not recommend using these nodes yet, since there is almost no documentation online. Furthermore they were created for a very specific scenario and can therefore only be used with additional soft- and hardware.

Intro

The generic term smart home describes among other things the increase of quality of life, security and reduction of energy consumption in our homes and workplaces through automated processes. These processes enable educators to work up realistic and tangible aspects of computing science using everyday examples. Programming, networks, communication protocols, web design and development, electrical engineering, data science, CAD and even project management can be combined with smart home in terms of content. For this reason, we have used open source tools to develop a cost-effective infrastructure that combines the above-mentioned aspects in a single kit.

The previous kit (IoT4School 1.x.x) was based on various in-house developed sensors and actuators based on the ESP8266, a Raspberry Pi as the central unit and Node-RED as the framework for linking the hardware. This hardware can be connected without writing code or previous knowledge, enables a quick experience of success while offering much potential for internal differentiation in teaching. However, it was quiet fiddly to get started, because of one layer PCB-design and the preparation time (etching, drilling, soldering, ressoldering..). For that reason, IoT4School is updated in order to use "off-the-shelf hardware" like the Wemos D1 Mini and the corresponding shields.

Details will be published soon in another paper.

Usage

The nodes were created to teach in computer science classes how IoT devices can work and how to create own smart home solutions. In order to achieve that, I created some sensors and actuators based on the ESP-12E module and correspondent firmware. All sources can be found at my git repository.

To utilize the nodes completely you will need a sqlite3 database, a webserver, a MQTT broker and python3. Each hardware module will initialy communicate with the python script "saymyname.py" to get an individual topic. For example: if you add the "Smart-Button" board to the infrastructure, it will ask "saymyname" for an individual name. When "Smart-Button" is the first modul of its kind in the database, it will receive the name Smart-Button0 and subscribe the topic sub/Sensor/Smart-Button/0 and publish data over the topic pub/Sensor/Smart-Buttpn/0. The procedure is aquivalent for actuator modules. Informations about all connected and previous connected devices can be found on the webserver.

Sensor Node

This nodes subscribes a sensor, e.g. Smart-Button0. Whenever Smart-Button0 publishes data with the identifier "data" in its payload, this node will forward the msg.

Aktor Node

This nodes publishes messages to an actuator. The payload has to be an JSON-Object.

An Node

Overwrites incoming messages to a "turn it on" command for actuators. Currently compatible to following hardware: rgb-controller, Yeelight bulbs and smart-socket.

Aus Node

Overwrites incoming messages to a "turn it off" command for actuators. Currently compatible to following hardware: rgb-controller, Yeelight bulbs and smart-socket.

Toggle Node

Overwrites incoming messages to a "toggle it" command for actuators. Currently compatible to following hardware: rgb-controller, yeelight bulbs and smart-socket.

RGB Node

If the incoming message is not a rgb or hex colour value, this node will add a "set colour" command to the payload. The colour is specified within the node. A great feature is, that the RGB node is compatible to the colour picker node from the node-red dashboard. This node can be used for the rgb-controller board or Yeelights. To use it for Yeelights you need to run the python3 script "wrapper.py" and enable developer mode on those bulbs.

Helligkeit Node

If the incoming message is not an integer or an string that can be parsed to an integer, this node will add a "set brightness" command to the payload. The brightness is specified within the node. This node can be used for the rgb-controller board or Yeelights. To use it for Yeelights you need to run the python3 script "wrapper.py" and enable developer mode on those bulbs.

Servo Node

If the incoming message is not an integer or an string that can be parsed to an integer, this node will add a "set angle" command to the payload. The angle is specified within the node. This node can be used for the servo-board.

Klick Dekodierer Node

This node is exclusive for the Smart-Button board. Klick Dekodierer can recognize several click patters, which this node decodes and routes towords one of the four outputs.

Wetter Dekodierer Node

This node is exclusive for the Weatherstation board. Wetter Dekodierer parses the payload from the weather station und routes the data towards the outputs. The temperature e.g. can be accessed via output 1.

Contact

Feel free to contact my via github or Twitter. I'd be grateful for feedback!