Determine the Orientation of an Accelerometer using a JavaScript function in Node-RED

Question

Determine the Orientation of an Accelerometer using a JavaScript function in Node-RED

Is there a way to determine the orientation of a sensor using a JavaScript function? I came across an example on 3D Accelerometer calculate the orientation, but I'm struggling to understand how to utilize the values of msg.payload.xAxis/yAxis/zAxis for the calculation. If possible, I would like to incorporate this into the sample payload below by creating a new field.

{
"device":"368640",
"deviceType":"Sigfox-Tracker",
"version":3,
"timestamp":"1535121228",
"rssi":"-113.00",
"battery":3.28,
"temp":21.5,
"soil":2107,
"xAxis":61,
"yAxis":-26,
"zAxis":994
}

javascript math

Answer 1

Answer №1

The text you provided seems to be a javascript object, and one way to access its properties is through dot notation, such as using data.xAxis.

I've created two functions based on this answer from your link. These functions utilize the built-in Math object for the provided formula.

Here's an example:

let data = {
  "device": "368640",
  "deviceType": "Sigfox-Tracker",
  "version": 3,
  "timestamp": "1535121228",
  "rssi": "-113.00",
  "battery": 3.28,
  "temp": 21.5,
  "soil": 2107,
  "xAxis": 61,
  "yAxis": -26,
  "zAxis": 994
}

function calcRoll(y, z){
  return Math.atan2(y, z) * 180/Math.PI;
}

function calcPitch(x, y, z){
  return Math.atan2(-x, Math.sqrt(y*y + z*z)) * 180/Math.PI;
}

let dataX = data.xAxis;
let dataY = data.yAxis;
let dataZ = data.zAxis;

let roll = calcRoll(dataY, dataZ);
let pitch = calcPitch(dataX, dataY, dataZ);

console.log(`roll is: ${roll} and pitch is ${pitch}`);

Answer 2

The text you provided seems to be a javascript object, and one way to access its properties is through dot notation, such as using data.xAxis.

I've created two functions based on this answer from your link. These functions utilize the built-in Math object for the provided formula.

Here's an example:

let data = {
  "device": "368640",
  "deviceType": "Sigfox-Tracker",
  "version": 3,
  "timestamp": "1535121228",
  "rssi": "-113.00",
  "battery": 3.28,
  "temp": 21.5,
  "soil": 2107,
  "xAxis": 61,
  "yAxis": -26,
  "zAxis": 994
}

function calcRoll(y, z){
  return Math.atan2(y, z) * 180/Math.PI;
}

function calcPitch(x, y, z){
  return Math.atan2(-x, Math.sqrt(y*y + z*z)) * 180/Math.PI;
}

let dataX = data.xAxis;
let dataY = data.yAxis;
let dataZ = data.zAxis;

let roll = calcRoll(dataY, dataZ);
let pitch = calcPitch(dataX, dataY, dataZ);

console.log(`roll is: ${roll} and pitch is ${pitch}`);

Answer 3

Answer №2

Hey Andrew, I'm wondering if this is the correct way to capture msg.payload since each payload contains different values?

let data = msg.payload

function calculateRoll(y, z){
  return Math.atan2(y, z) * 180/Math.PI;
}

function calculatePitch(x, y, z){
  return Math.atan2(-x, Math.sqrt(y*y + z*z)) * 180/Math.PI;
}

let dataX = data.xAxis;
let dataY = data.yAxis;
let dataZ = data.zAxis;

let roll = calculateRoll(dataY, dataZ);
let pitch = calculatePitch(dataX, dataY, dataZ);

msg.payload.roll = roll;
msg.payload.pitch = pitch;
return msg;

This is the debug message I see in Node-RED when the updated payload arrives:

{"device":"368640","deviceType":"Sigfox-Tracker","version":3,"timestamp":"1535136195","rssi":"-109.00","battery":3.28,"temp":19.5,"soil":2105,"xAxis":71,"yAxis":-32,"zAxis":1002,"roll":-1.8291836314227448,"pitch":-4.05104777734416}

Answer 4

Hey Andrew, I'm wondering if this is the correct way to capture msg.payload since each payload contains different values?

let data = msg.payload

function calculateRoll(y, z){
  return Math.atan2(y, z) * 180/Math.PI;
}

function calculatePitch(x, y, z){
  return Math.atan2(-x, Math.sqrt(y*y + z*z)) * 180/Math.PI;
}

let dataX = data.xAxis;
let dataY = data.yAxis;
let dataZ = data.zAxis;

let roll = calculateRoll(dataY, dataZ);
let pitch = calculatePitch(dataX, dataY, dataZ);

msg.payload.roll = roll;
msg.payload.pitch = pitch;
return msg;

This is the debug message I see in Node-RED when the updated payload arrives:

{"device":"368640","deviceType":"Sigfox-Tracker","version":3,"timestamp":"1535136195","rssi":"-109.00","battery":3.28,"temp":19.5,"soil":2105,"xAxis":71,"yAxis":-32,"zAxis":1002,"roll":-1.8291836314227448,"pitch":-4.05104777734416}

Determine the Orientation of an Accelerometer using a JavaScript function in Node-RED

Answer №1

Answer №2

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