Terminal Widget

📊 Chart

The Terminal widget displays a scrolling log of text values sent to a virtual pin — like a serial monitor in the cloud. Lines are timestamped and color-coded optionally. You can also type commands and send them to the device (bidirectional mode).

Default size: 3 × 3 grid cells

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Configuration

Property	Type	Default	Description
maxLines	number	100	Maximum lines kept in view
showTimestamp	boolean	true	Prepend each line with time
Device	device	—	The device to read/write
Pin	V0–V255	—	The virtual pin for I/O
Label	string	—	Widget label

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Sending logs to the terminal

// Any string pushed to the pin appears as a new line
void loop() {
  Vwire.run();

  if (sensorError) {
    Vwire.virtualSend(V10, "ERROR: sensor read failed");
  }

  float v = readVoltage();
  char buf[64];
  snprintf(buf, sizeof(buf), "Voltage: %.2f V", v);
  Vwire.virtualSend(V10, buf);

  delay(5000);
}

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Bidirectional: receive commands from terminal

VWIRE_RECEIVE(V10) {
  String cmd = param.asStr();

  if (cmd == "reset") {
    ESP.restart();
  } else if (cmd.startsWith("setpin ")) {
    int pin = cmd.substring(7).toInt();
    digitalWrite(pin, HIGH);
    Vwire.virtualSend(V10, "OK");
  } else {
    Vwire.virtualSend(V10, "Unknown command: " + cmd);
  }
}

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Log levels by convention

Since VWire sends raw strings, you can prefix lines to implement logging levels:

#define LOG_INFO(msg)  Vwire.virtualSend(V10, "[INFO]  " msg)
#define LOG_WARN(msg)  Vwire.virtualSend(V10, "[WARN]  " msg)
#define LOG_ERROR(msg) Vwire.virtualSend(V10, "[ERROR] " msg)

// Usage
LOG_INFO("Boot complete");
LOG_WARN("Low battery: 12%");
LOG_ERROR("Sensor timeout");