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How to Decode MDAD

The MDAD (Multidimensional Array of Data) is an ordered numeric array. Read values using their zero-based channel numbers, not by treating 0–119 as a 10-row by 12-column emotion table. These channel definitions follow the EPU-III Brochure, pages 14–15, and are used by this page's live Emo-Graph and APEX table.

1. Read the 12 emotion APEX channels

Each ten-channel group starts at 10 × emotionIndex. The emotion APEX is at channel offset 4 (the fifth array position because indexing starts at zero); the associated feeling is at offset 9 (the tenth position). Channel 10 begins the next emotion group. For example, Excite APEX is mdad[4], Optimistic feeling is mdad[9], and Fear APEX is mdad[54].

The 12 primary emotion APEX readings are the only values included in the live APEX table and radial Emo-Graph. No averaging across channels or substitution of a consecutive 12-value row is needed.

In Swagger, Example Value is static sample data, not a reading from your EPUID. After clicking Execute, use Server response → Response body to inspect the actual MDAD values.

2. Read Optimistic and the other status channels

The channel 121 direction shown below follows current operator testing: values below 50 indicate satisfaction or relief of frustration, and values above 50 indicate frustration. The older EPU-III brochure labelled this channel in the opposite direction. Channel 122 values below 50 indicate pleasure or relief of pain, and values above 50 indicate pain. Confirm firmware-specific semantics before using either channel for decisions.

3. Extract the data in JavaScript

Use this same decoder for the array returned by GET /mdad and for the mdad payload delivered over Socket.IO. The code keeps the raw values intact and checks that at least 120 numeric channels are present. Treat APEX, Optimistic and optional channels 121–122 outside 0–100 as invalid, not as valid endpoints; preserve their raw values for diagnosis.

// mdad is the numeric array from GET /mdad or the Socket.IO "mdad" event.
function decodeMDAD(mdad) {
  if (!Array.isArray(mdad) || mdad.length < 120 ||
      !mdad.every(value => typeof value === 'number' && Number.isFinite(value))) {
    throw new Error('Expected an MDAD array with at least 120 finite numbers');
  }

  const emotionNames = [
    'Excite', 'Confident', 'Happy', 'Trust',
    'Desire', 'Fear', 'Surprise', 'Inattention',
    'Sad', 'Nostalgia', 'Disgust', 'Anger'
  ];
  const levelIndexes = [9, ...emotionNames.map((_, i) => 4 + 10 * i), 121, 122];
  const invalidLevels = levelIndexes.filter(i => i < mdad.length &&
    (mdad[i] < 0 || mdad[i] > 100)).map(i => ({ index: i, raw: mdad[i] }));
  const level = i => mdad.length > i && mdad[i] >= 0 && mdad[i] <= 100 ? mdad[i] : null;
  const emotions = Object.fromEntries(
    emotionNames.map((name, i) => [name, level(4 + 10 * i)])
  );
  const optional = channel => mdad.length > channel ? mdad[channel] : null;

  return {
    emotions,                            // 12 emotion APEX values
    optimistic: level(9),                // feeling, not an emotion APEX
    pulseSpeed: optional(120),
    frustrationSatisfaction: level(121),
    painPleasure: level(122),
    temperature: optional(123),
    invalidLevels                          // retain raw mdad unchanged for diagnostics
  };
}

// REST: const reading = decodeMDAD(response.mdad);
// Socket.IO (after connecting to the EPU namespace):
socket.on('mdad', ({ mdad }) => {
  console.log(decodeMDAD(mdad)); // update your own dashboard here
});

In a real-time application, decode each new frame once and update the emotion graph, APEX table and feeling/status cards from that same frame. Avoid using stale values from earlier frames when optional channels are absent.

Channel descriptions based on EPU-III Brochure, pp. 14–15 (emotional data and MDAD buffer structure). Live connection and API behavior follow the EPU4 SDK integration guide.