Rainbow Lighting Function

[Bryan_Fleming (Bryan)]

I am fairly new to node-red and JavaScript and I am trying to write a function to generate a smooth rainbow effect across a row of 6 RGB lights. The idea is to have the rainbow run dusk to dawn. The lights I am trying to trigger are DMX landscape lights that are set up in HA via the Home Assistant DMX over IP Light Platform (Art-Net) integration.

Here’s what I’ve got so far:

[{"id":"6fced553.1b116c","type":"function","z":"8a65e184.b6b8a","name":"Rainbow Effect","func":"var numberOfLEDs = 6;\n\nfor(i=0; i<255; i++){\n    \n    for(j=0; j<numberOfLEDs; j++){\n        \n        var pos = 0;\n        pos = Math.round(((j*255/numberOfLEDs)+i))&255;\n        \n        if(pos<85){\n            var red = pos*3;\n            var green = 255-pos*3;\n            var blue = 0;\n        }\n        else if(pos < 170){\n            pos -= 85;\n            var red = 255 - pos*3;\n            var green = 0;\n            var blue = pos*3;\n        }\n        else{\n            pos -= 170;\n            var red = 0;\n            var green = pos*3;\n            var blue = 255-pos*3;\n        }\n \n        var rgb_color = red +','+ green +','+ blue;\n        var entity_id = 'light.pridegroup'+ j;\n        \n        node.send({payload:'{\"entity_id\": \"' + entity_id + '\", \"rgb_color\": \"' + rgb_color +'\"}'});\n    }\n}","outputs":1,"noerr":0,"x":480,"y":260,"wires":[["72d96033.8598d"]]}]

Rainbow function credit: https://randomnerdtutorials.com/node-red-with-ws2812b-addressable-rgb-led-strip/

I seem to be having issues passing the correct payload to the service call. I would love some help getting this over the finish line. Thanks!

[Kermit]

entity_id and rbg_color should be in the data property of msg.payload

node.send({payload: {data: { entity_id: entity_id, rgb_color: rgb_color}}});

or

msg.payload = {
    data: {
        entity_id: entity_id,
        rgb_color: rgb_color,
    },
};
node.send(msg);

[Bryan_Fleming (Bryan)]

I’m getting the following error trying to pass these values to HA.

I’m using your second example, and the RGB values appear to be sent in a string. But, shouldn’t it be an array?

I’m struggling with how to get it formatted correctly.

[Kermit]

This is creating a string when you want an array.

var rgb_color = red +','+ green +','+ blue;

const rgb_color = [red, green, blue];