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Calibration

This guide will help you calibrate your Crimpdeq device to ensure accurate weight measurements. The calibration process involves using a known weight to establish a reference point for the device’s measurements.

Prerequisites

  • nRF Connect installed for your platform:
  • A stable mounting point so the device hangs freely and remains still
  • One known weight (ideally near your typical maximum load)

Calibration Steps

  1. Connect to Crimpdeq with nRF Connect:
    1. Launch the app and go to the Scanner tab.
    2. Find the device named “Progressor_7125” and tap “Connect”.
    3. Once connected, the app will display the device’s services and characteristics.
      nRF Discovered
  2. Locate the calibration characteristic:
    1. Expand the “Unknown Service” section.
    2. Find the characteristic with UUID: 7e4e1703-1ea6-40c9-9dcc-13d34ffead57.
      Services
  3. Compute the hex value of your known weight:
    1. Open the Floating Point to Hex Converter.
    2. Select “Single-precision” (32-bit) floating point.
    3. Enter your known weight in the “Float value” field (in kilograms unless your device expects grams; see Important Notes).
    4. Click “Convert to hex” and save the resulting “Hex value”.
      Example: 75.3 kg → 0x4296999a.
  4. Zero the device (tare):
    1. Hang Crimpdeq with no weight attached.
    2. Send the command 7300000000 to the characteristic:
      • Tap the Up Arrow icon on the characteristic (7e4e1703-1ea6-40c9-9dcc-13d34ffead57).
      • Enter the command as shown.
        Send weight
  5. Perform the calibration:
    • Commands and values are hex strings without spaces (letter case does not matter).
    1. Attach your known weight to Crimpdeq.
    2. Build the calibration command by prefixing 73 to your hex value.
      • Example: For 75.3 kg (0x4296999a), send: 734296999a.
    3. Send this command to the same characteristic (7e4e1703-1ea6-40c9-9dcc-13d34ffead57).
  6. Verify:
    1. Remove the weight and reattach it.
    2. The reported value should be within a small tolerance of the known weight. If not, repeat steps 4–5.

Important Notes

  • Units: Some devices expect the calibration value in grams instead of kilograms. If, after calibration, the measured value looks off by a factor of ~100 (e.g., 75.3 kg shows ~0.75), convert your known weight to grams and repeat step 5.
  • Use a weight close to the maximum load you expect to measure (while staying within device limits) for best accuracy.
  • Ensure the device is stable and stationary when sending commands.
  • Perform calibration in a controlled environment (avoid wind, vibration, and temperature swings).