node-red-contrib-rflink

[ghost]

Hello Maxwell,

any chance of making a RFLINK node or adapt your excisting one to as i heard that both protocols are quite similiar ?

http://www.nemcon.nl/blog2/

You can build yourself a gateway for only about 10 dollars with Arduino Mega and there are a lot of 433 devices supported.... I already tried it with your node-red-contrib-rfxcom node modules but except of showing me a green light when connecting to the serial port, its giving me errors.

[maxwellhadley]

Looking at the RFLink API documentation the protocol at the serial port level is completely different. However, as it uses a text format instead of binary, it should be possible to control it from node-red using a serialport node, maybe with a couple of function nodes to convert payload and topic to the right command string. You also need to set the baud rate to 57600 which is different from the RFXtrx433.

[ghost]

Thank you Max for your quick reply! I already did that in node-red and as you said using the right serialport values its giving me debug-output like "20;99;LaCrosse;ID=0400;HUM=76;" for my old 433 weather-station. When using the "switch-node" i can seperate the incoming payloads via IDs into topics, but how can i for example convert the "20;99;LaCrosse;ID=0400;HUM=76;" payload to extract only the actual "76" value? Also the incoming temperature payload (20;9A;LaCrosse;ID=0400;TEMP=0001;) is hexadecimal, so what could be a function to translate that into decimal payload ? Thanks for your help

[maxwellhadley]

This type of thing is simplest to do in a function node. Here is an example flow where I use inject nodes to send the messages you quoted, and a function node to split them apart.

The Javascript split() method (of the String class) takes the string to which it applies, and breaks it apart into sections delimited by the ';' character passed as a parameter. It creates an Array of strings, e.g. ['20', '99', 'LaCrosse', 'ID=0400', 'HUM=76']. The array indexes start at 0, so parts[4] contains the actual reading. I use split() again, this time splitting on the '=' character. I test whether the name part data[0] is 'HUM' or 'TEMP' and process the value part appropriately. The second argument to parseInt() tells it what base to use, in this case 16 for hexadecimal. This function parses an integer from a string, but like all Javascript numbers, its return value is a floating-point number. You can multiply this by an appropriate scaling factor, if required. Finally assign the result to msg.payload and return:

[ { "id": "3bc1edc.98c7592", "type": "inject", "z": "e09a97d6.a30b6", "name": "LaCrosse humidity", "topic": "RFlink", "payload": "20;99;LaCrosse;ID=0400;HUM=76", "payloadType": "str", "repeat": "", "crontab": "", "once": false, "x": 136.5, "y": 57, "wires": [ [ "2f76b1fa.f12b06", "34c2a160.1fa65e" ] ] }, { "id": "2f76b1fa.f12b06", "type": "debug", "z": "e09a97d6.a30b6", "name": "", "active": true, "console": "false", "complete": "true", "x": 403.5, "y": 86, "wires": [] }, { "id": "34c2a160.1fa65e", "type": "function", "z": "e09a97d6.a30b6", "name": "Message splitting", "func": "var parts, data;\nparts = msg.payload.split(\";\");\ndata = parts[4].split(\"=\");\nif (data[0] === 'HUM') {\n msg.payload = data[1];\n} else if (data[0] === 'TEMP') {\n msg.payload = parseInt(data[1], 16);\n}\nreturn msg;", "outputs": 1, "noerr": 0, "x": 298.5, "y": 180, "wires": [ [ "2f76b1fa.f12b06" ] ] }, { "id": "f6e721b7.9ebcc", "type": "inject", "z": "e09a97d6.a30b6", "name": "LaCrosse temperature", "topic": "RFlink", "payload": "20;99;LaCrosse;ID=0400;TEMP=001a", "payloadType": "str", "repeat": "", "crontab": "", "once": false, "x": 147, "y": 270, "wires": [ [ "34c2a160.1fa65e" ] ] } ]

[maxwellhadley]

Now that https://flows.nodered.org/node/node-red-contrib-rflink is published, I'll close this issue.