Bar Chart Widget

📊 Chart

The Bar Chart widget renders a vertical or horizontal bar chart from discrete labeled values. Unlike the Graph widget (which plots a time series), the Bar Chart shows a snapshot comparison — e.g. power consumption per channel, counts per category, or daily totals.

Default size: 4 × 3 grid cells

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Configuration

Property	Type	Default	Description
orientation	vertical | horizontal	vertical	Bar direction
color	hex color	#6366F1	Bar fill color
colors	hex[]	[]	Per-bar colors (overrides color)
Device	device	—	The device to read from
Pin	V0–V255	—	The virtual pin providing data
Label	string	—	Widget label

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Data format

The device sends a JSON array of {label, value} objects:

[
  { "label": "CH1", "value": 120 },
  { "label": "CH2", "value": 85  },
  { "label": "CH3", "value": 200 },
  { "label": "CH4", "value": 45  }
]

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Firmware example: 4-channel power monitor

float power[4] = {0};

void readPower() {
  for (int i = 0; i < 4; i++)
    power[i] = readChannel(i);
}

void sendBarChart() {
  char buf[256];
  snprintf(buf, sizeof(buf),
    "[{\"label\":\"CH1\",\"value\":%.1f},"
    "{\"label\":\"CH2\",\"value\":%.1f},"
    "{\"label\":\"CH3\",\"value\":%.1f},"
    "{\"label\":\"CH4\",\"value\":%.1f}]",
    power[0], power[1], power[2], power[3]);

  Vwire.virtualSend(V0, buf);
}

void loop() {
  Vwire.run();
  readPower();
  sendBarChart();
  delay(5000);
}

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Tips

• Maximum of 12 bars is recommended for readability.
• Use per-bar colors for categorical data (e.g. phase colors in a 3-phase system).
• For time-series bar data (hourly totals), use data already aggregated on the device before sending.