FFT Data API

The FFT Data API provides endpoints for retrieving Fast Fourier Transform (FFT) frequency analysis data from vibration sensors. FFT data is essential for identifying specific frequency components that indicate mechanical issues such as imbalance, misalignment, or bearing defects.

Endpoints Overview

Method	Endpoint	Description
GET	/fft-data	List FFT data records
GET	/fft-data/{id}	Get specific FFT data

List FFT Data

Retrieves FFT data records with optional filtering.

Endpoint: GET /fft-data

Authentication: Required

Query Parameters:

Parameter	Type	Description
sensorId	string	Filter by sensor identifier
timestamp	string	Filter by timestamp (ISO 8601)
limit	integer	Maximum number of results (default: 100)

Response:

{
  "items": [
    {
      "id": "fft-123",
      "sensorId": "sensor-456",
      "timestamp": "2024-10-15T14:30:00Z",
      "samplingRate": 25600,
      "resolution": 1.0,
      "frequencyRange": {
        "min": 0,
        "max": 12800
      },
      "spectrum": {
        "frequencies": [0, 1, 2, 3, 4, 5],
        "amplitudes": [0.01, 0.15, 0.08, 0.45, 0.12, 0.03]
      },
      "peaks": [
        {
          "frequency": 29.5,
          "amplitude": 2.34,
          "order": 1,
          "label": "1X RPM"
        },
        {
          "frequency": 59.0,
          "amplitude": 0.89,
          "order": 2,
          "label": "2X RPM"
        }
      ],
      "rpm": 1770,
      "createdAt": "2024-10-15T14:30:05Z",
      "updatedAt": "2024-10-15T14:30:05Z"
    }
  ],
  "count": 1,
  "nextToken": "eyJpZCI6ImZmdC0xMjMifQ=="
}

Example Request:

curl -X GET "https://api.acme.f7i.ai/prod/fft-data?sensorId=sensor-456&limit=50" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json"

Get FFT Data

Retrieves a specific FFT data record by ID.

Endpoint: GET /fft-data/{id}

Authentication: Required

Path Parameters:

Parameter	Type	Description
id	string	Unique identifier of the FFT data record

Response:

{
  "id": "fft-123",
  "sensorId": "sensor-456",
  "timestamp": "2024-10-15T14:30:00Z",
  "samplingRate": 25600,
  "resolution": 1.0,
  "frequencyRange": {
    "min": 0,
    "max": 12800
  },
  "spectrum": {
    "frequencies": [0, 1, 2, 3, 4, 5],
    "amplitudes": [0.01, 0.15, 0.08, 0.45, 0.12, 0.03]
  },
  "peaks": [
    {
      "frequency": 29.5,
      "amplitude": 2.34,
      "order": 1,
      "label": "1X RPM"
    },
    {
      "frequency": 59.0,
      "amplitude": 0.89,
      "order": 2,
      "label": "2X RPM"
    }
  ],
  "rpm": 1770,
  "createdAt": "2024-10-15T14:30:05Z",
  "updatedAt": "2024-10-15T14:30:05Z"
}

Example Request:

curl -X GET "https://api.acme.f7i.ai/prod/fft-data/fft-123" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json"

Understanding FFT Data

Spectrum Data

The spectrum object contains:

• frequencies: Array of frequency values in Hz
• amplitudes: Corresponding amplitude values (typically in mm/s or g)

Peak Detection

The peaks array identifies significant frequency components:

• frequency: Peak frequency in Hz
• amplitude: Peak amplitude
• order: Harmonic order relative to running speed (1X, 2X, etc.)
• label: Human-readable description

Common Frequency Signatures

Order	Common Causes
1X	Imbalance, bent shaft
2X	Misalignment, looseness
3X-5X	Coupling issues
BPFO/BPFI	Bearing defects
Gear mesh	Gear tooth issues

Error Responses

400 Bad Request

{
  "error": "Invalid request",
  "details": {
    "sensorId": "Sensor ID is required"
  }
}

404 Not Found

{
  "error": "Item not found"
}

500 Internal Server Error

{
  "error": "Internal server error: [error details]"
}