mharizanov: NodeRED RFM2Pi to emonCMS gateway

I created a Node-RED RFM2Pi gateway few weeks ago, have it running nicely since then. I decided to use that approach instead of a python script, since it is very flexible, visual and easy to extend. Prior to Node-RED I used the great OEM gateway script by Jérôme Lafréchoux. My inspiration to switch to Node-RED were Nathan Chantrell’s posts and tweets and Don Bramey’s work.

Getting Node-RED installed on Raspberry Pi is best described on Adafruit’s site [Edit: see Ukmoose' comment below on node.js version]. Should be straightforward for most. In addition, I installed MQTT:

sudo apt-get install mosquitto

The idea of the gateway is to

• Interface with the RFM2Pi board
• Forward all incoming wireless packets to EmonCMS for logging and further analysis
• Send current time to wireless nodes like EmonGLCD

Here are the Node-RED flows

The RFM2Pi flow containing the inbound and outbound functions

This uses the so called ‘multinode’ approach, i.e. doesn’t really decode or understand what is being sent. It just captures the payload and publishes it to a MQTT topic

The RFM2Pi sender function

And here is the source code for this flow:

 
[{"id":"b7108ab7.48ef78","type":"serial-port","serialport":"/dev/ttyAMA0","serialbaud":"9600","newline":"\\r\\n","addchar":"true"},{"id":"ba386057.845d3","type":"mqtt-broker","broker":"localhost","port":"1883"},{"id":"4daa1376.b255ec","type":"function","name":"Parse RF12B ","func":"//we are expecting data in form \" nodeid data1 data2 etc\"\nmsg.payload = msg.payload.trim();\n\nvar tokens = msg.payload.split(\" \",66); //FM2Pi will have max of 66 bytes payload\nvar outString = null;\nvar outTopic = null;\nvar msg2 = null;\nvar nodeid = tokens.shift();\n\nif(!isNaN(nodeid)) {\n\tnodeid = nodeid & 0x1F; // Strip out the additional flags\n\tvar raw= tokens;\n\tbuf = new Buffer(raw);\n\toutString = [];\n\tfor (var i=0; i<=(tokens.length/2); i+=2) {\n\t\toutString.push( buf.readInt16LE(i) );\n\t}\t\n\t//console.log(outString);\n\toutTopic = 'rfm12b/' + nodeid;\n\tmsg2 = { payload:outString, topic:outTopic};\n}\nreturn msg2;","outputs":"1","x":277,"y":111,"z":"437a6787.bc8598","wires":[["d02f9e7.f2fd06"]]},{"id":"d02f9e7.f2fd06","type":"mqtt out","name":"RFM12B IN","topic":"","broker":"ba386057.845d3","x":456,"y":111,"z":"437a6787.bc8598","wires":[]},{"id":"2a97ab9.fd56854","type":"serial in","name":"","serial":"b7108ab7.48ef78","x":89,"y":111,"z":"437a6787.bc8598","wires":[["4daa1376.b255ec","512b148f.aed4ec"]]},{"id":"1af69d77.e50963","type":"mqtt in","name":"RFM12B OUT","topic":"rfm12b/out","broker":"ba386057.845d3","x":86,"y":304,"z":"437a6787.bc8598","wires":[["80d0c97c.7f2f38"]]},{"id":"80d0c97c.7f2f38","type":"function","name":"Send to Node","func":"// The received message is stored in 'msg'\n// It will have at least a 'payload' property:\n//   console.log(msg.payload);\n// The 'context' object is available to store state\n// between invocations of the function\n//   context = {};\n\nvar dataStr = msg.payload;\n\n//if individual node selected - the destination id should be last part of topic\nvar tokens = msg.topic.split(\"/\");\nvar dest = tokens[tokens.length-1];\n\nif(dest == \"out\")\n{\n   dest = \"0\";\n}\nif(isNaN(dest))\n{\n  dataStr='NAN';\n  //return null;\n}\nmsg.payload = dataStr + \",\" + dest + \"s\";\nreturn msg;","outputs":1,"x":271,"y":305,"z":"437a6787.bc8598","wires":[["906cd828.6f9328"]]},{"id":"512b148f.aed4ec","type":"debug","name":"Serial In Debug","active":false,"complete":"false","x":285.42852783203125,"y":183.85711669921875,"z":"437a6787.bc8598","wires":[]},{"id":"ff2da801.00d258","type":"comment","name":"RFM2Pi Inbound ","info":"","x":81,"y":58,"z":"437a6787.bc8598","wires":[]},{"id":"6bb839bd.9447c8","type":"comment","name":"RFM2Pi Outbound","info":"","x":88,"y":258,"z":"437a6787.bc8598","wires":[]},{"id":"67bfcebf.98403","type":"serial out","name":"","serial":"b7108ab7.48ef78","x":634,"y":304,"z":"437a6787.bc8598","wires":[]},{"id":"113cd655.eec32a","type":"debug","name":"Sender Debug","active":true,"complete":"false","x":570,"y":419,"z":"437a6787.bc8598","wires":[]},{"id":"906cd828.6f9328","type":"delay","name":"Delay 5ms","pauseType":"delay","timeout":"5","timeoutUnits":"milliseconds","rate":"1","rateUnits":"second","randomFirst":"1","randomLast":"5","randomUnits":"seconds","x":432,"y":306,"z":"437a6787.bc8598","wires":[["67bfcebf.98403","113cd655.eec32a"]]}]

Next is the EmonCMS interface flow:

Most interesting is the “Prepare for EmonCMS” function:

Mind to place your API key here, emoncms URL as well, if it is not default

And the source code for this flow is:

[{"id":"ba386057.845d3","type":"mqtt-broker","broker":"localhost","port":"1883"},{"id":"909bcfcf.6f643","type":"mqtt in","name":"Send to Emoncms","topic":"home/emoncms/out/#","broker":"ba386057.845d3","x":84.00000762939453,"y":87,"z":"fea0be35.015f4","wires":[["8ebc9733.714368"]]},{"id":"8ebc9733.714368","type":"function","name":"Build EmonCMS url","func":"// The received message is stored in 'msg'\n// It will have at least a 'payload' property:\n//   console.log(msg.payload);\n// The 'context' object is available to store state\n// between invocations of the function\n//   context = {};\n\n//expects JSON payload and destination specified in topic\n\nvar key = \"**** YOUR API *****\";\n\n//destination will be last part node of topic\nvar tokens = msg.topic.split(\"/\");\nvar dest = tokens[tokens.length-1];\n\n\nif(isNaN(dest))\n{\n//not a valid destination\nreturn null;\n}\n\nmsg.url =\"http://emoncms.org/input/post.json?node=\";\nmsg.url += dest;\nmsg.url += \"&json=\";\nmsg.url += msg.payload;\nmsg.url += \"&apikey=\";\nmsg.url += key;\n\n\nreturn msg;","outputs":1,"x":285.00001525878906,"y":119,"z":"fea0be35.015f4","wires":[["f9933cd6.066cc","bef8a264.41076"]]},{"id":"f9933cd6.066cc","type":"http request","name":"HTTP GET to EmonCMS","method":"GET","url":"","x":513.6667175292969,"y":99,"z":"fea0be35.015f4","wires":[["87f944f6.7806b8"]]},{"id":"87f944f6.7806b8","type":"debug","name":"EmonCMS HTTP Request Result","active":false,"complete":"false","x":713.6666870117188,"y":31.333343505859375,"z":"fea0be35.015f4","wires":[]},{"id":"a8c85fa8.5737a","type":"debug","name":"EmonCMS URL","active":false,"complete":"true","x":702,"y":164,"z":"fea0be35.015f4","wires":[]},{"id":"bef8a264.41076","type":"function","name":"Debug EmonCMS URL","func":"// The received message is stored in 'msg'\n// It will have at least a 'payload' property:\n//   console.log(msg.payload);\n// The 'context' object is available to store state\n// between invocations of the function\n//   context = {};\n\n\nreturn msg.url;","outputs":1,"x":517,"y":163,"z":"fea0be35.015f4","wires":[["a8c85fa8.5737a"]]},{"id":"788069a.f877f98","type":"mqtt in","name":"RFM12B IN","topic":"rfm12b/#","broker":"ba386057.845d3","x":65,"y":289,"z":"fea0be35.015f4","wires":[["ca153b2d.35eac8"]]},{"id":"314a8d67.ceb572","type":"mqtt out","name":"Send to Emoncms","topic":"","broker":"ba386057.845d3","x":502,"y":289,"z":"fea0be35.015f4","wires":[]},{"id":"ca153b2d.35eac8","type":"function","name":"Prepare for EmonCMS","func":"// The received message is stored in 'msg'\n// It will have at least a 'payload' property:\n//   console.log(msg.payload);\n// The 'context' object is available to store state\n// between invocations of the function\n//   context = {};\n\n//destination will be last part node of topic\nvar tokens = msg.topic.split(\"/\");\nvar dest = tokens[tokens.length-1];\n\nmsg.topic = \"home/emoncms/out/\";\nmsg.topic += dest;\n\nreturn msg;\n","outputs":1,"x":270,"y":290,"z":"fea0be35.015f4","wires":[["314a8d67.ceb572"]]},{"id":"b8e15d04.471ea","type":"comment","name":"EmonCMS sender","info":"","x":84,"y":44,"z":"fea0be35.015f4","wires":[]},{"id":"7a28503a.85d7b","type":"comment","name":"Send whatever was received on the RFM12B/# MQTT topic to EmonCMS","info":"","x":258,"y":234,"z":"fea0be35.015f4","wires":[]}]

The final component is the time sender flow:

I have an inject node that kicks in every minute, you can reduce that to whatever is necessary. Most of the work is done in the “Prepare Time Packet” function:

And the source code is:

[{"id":"ba386057.845d3","type":"mqtt-broker","broker":"localhost","port":"1883"},{"id":"df2824d5.20d7d8","type":"inject","name":"Inject time","topic":"","payload":"","repeat":"","crontab":"*/1 * * * *","once":true,"x":196,"y":179,"z":"7733bcb0.88cc44","wires":[["431cf1b3.bce31"]]},{"id":"431cf1b3.bce31","type":"function","name":"Prepare Time Packet","func":"// The received message is stored in 'msg'\n// It will have at least a 'payload' property:\n//   console.log(msg.payload);\n// The 'context' object is available to store state\n// between invocations of the function\n//   context = {};\n\nvar date = new Date;\ndate.getTime();\n\nvar minutes = date.getMinutes();\nvar hour = date.getHours();\n\n//00,20,23,00,s\n\nmsg.payload = '0,' + hour + ',' + minutes + ',0';\nmsg.topic = 'rfm12b/out';\n\nreturn msg;","outputs":1,"x":397,"y":197,"z":"7733bcb0.88cc44","wires":[["36026f66.c9fd9"]]},{"id":"36026f66.c9fd9","type":"mqtt out","name":"RFM12B Sender","topic":"","broker":"ba386057.845d3","x":608,"y":225,"z":"7733bcb0.88cc44","wires":[]}]

As conclusion, I believe Node-RED is the future of IoT wiring. Do get started with it.

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