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ReadMe Raspberry Pi v2
There are (at least) two ways for interacting with a Raspberry Pi using Node-RED.
gpio command : this provides nodes in the palette for monitoring and controlling the GPIO pins
wiring-pi module : this provides complete access to the GPIO pins, and other devices, within Function nodes.
The gpio command is part of @drogon WiringPi suite of tools.
This provides a way of controlling the GPIO pins via a simple command. It also supports accessories such as the PiFace and others and so provides a good platform for these integrations. For full details see the WiringPi website.
After installing Node-RED, follow these instructions to get WiringPi installed. Ensure that the test commands work.
Once you restart Node-RED you should now see two rpi-gpio nodes in the advanced section of the pallette. One to read from pins, and one to control pins.
To run a "blink" flow that toggles an LED on Pin 11 of the GPIO header, you will need to connect up an LED as described here.
Then copy the following flow and paste it into the Import Nodes dialog (Import From - Clipboard in the dropdown menu, or Ctrl-I). After clicking okay, click in the workspace to place the new nodes.
[{"id":"ae05f870.3bfc2","type":"function","name":"Toggle 0/1 on input","func":"\ncontext.state = context.state || 0;\n\n(context.state == 0) ? context.state = 1 : context.state = 0;\nmsg.payload = context.state;\n\nreturn msg;","outputs":1,"x":348.1666488647461,"y":146.16667652130127,"wires":[["1b0b73e9.14712c","b90e5005.a7c3b8"]]},{"id":"1b0b73e9.14712c","type":"debug","name":"","active":true,"x":587.1666488647461,"y":206.1666774749756,"wires":[]},{"id":"7aa75c69.fd5894","type":"inject","name":"tick every 1 sec","topic":"","payload":"","repeat":"1","crontab":"","once":false,"x":147.1666488647461,"y":146.1666774749756,"wires":[["ae05f870.3bfc2"]]},{"id":"b90e5005.a7c3b8","type":"rpi-gpio out","name":"","pin":"7","x":585.0000114440918,"y":146.00001049041748,"wires":[]}]
Click the deploy button and the flow should start running. The LED should start toggling on and off once a second.
This version of working with the Raspberry Pi uses a node.js wrapper to the WiringPi libraries previously installed, and so gives all functions you write access to the Pi capabilities at all times, so you can do more complex things, at the expense of having to write code within a function rather than dragging and wiring nodes.
After installing Node-RED, follow these instructions to get Wiring Pi installed.
Firstly the npm module needs to be installed into the node-red directory.
cd /node-red
npm install wiring-pi
This does not any specific nodes to Node-RED. Instead the Wiring-Pi module can be made available for use in Function nodes.
To do this, update settings.js to add the wiring-pi module to the Function
global context:
functionGlobalContext: {
wpi: require('wiring-pi')
}
The module is then available to any functions you write as context.global.wpi.
To run a "blink" flow that uses the WiringPi pin 0 - Pin 11 on the GPIO header, you will need to connect up an LED as described here.
Then copy the following flow and paste it into the Import Nodes dialog (Import From - Clipboard in the dropdown menu, or Ctrl-I). After clicking okay, click in the workspace to place the new nodes.
[{"id":"860e0da9.98757","type":"function","name":"Toggle LED on input","func":"\n// select wpi pin 0 = pin 11 on header (for v2)\nvar pin = 0;\n\n// initialise the wpi to use the global context\nvar wpi = context.global.wpi;\n\n// use the default WiringPi pin number scheme...\nwpi.setup();\n\n// initialise the state of the pin if not already set\n// anything in context. persists from one call to the function to the next\ncontext.state = context.state || wpi.LOW;\n\n// set the mode to output (just in case)\nwpi.pinMode(pin, wpi.modes.OUTPUT);\n\n// toggle the stored state of the pin\n(context.state == wpi.LOW) ? context.state = wpi.HIGH : context.state = wpi.LOW;\n\n// output the state to the pin\nwpi.digitalWrite(pin, context.state);\n\n// we don't \"need\" to return anything here but may help for debug\nreturn msg;","outputs":1,"x":333.16666412353516,"y":79.16666793823242,"wires":[["574f5131.36d0f8"]]},{"id":"14446ead.5aa501","type":"inject","name":"tick","topic":"","payload":"","repeat":"1","once":false,"x":113.16666412353516,"y":59.16666793823242,"wires":[["860e0da9.98757"]]},{"id":"574f5131.36d0f8","type":"debug","name":"","active":true,"x":553.1666641235352,"y":99.16666793823242,"wires":[]}]
Click the Deploy button and the flow should start running. The LED should start
toggling on and off once a second.
The easiest way to autostart Node-RED is to use screen so you can get to the
console at any time.
To install screen, if it is not already there, run:
$ sudo apt-get install screen
Then edit the /etc/rc.local file to include the lines:
cd /home/pi/node-red-master
screen -dmS red node red.js
This assumes that you have installed Node-RED to the default (pi) user's home directory.
Once you reboot you should then be able to attach to the screen session by running:
$ screen -r red
To detach from the session, type Ctrl-A-D.