serial-in

Overview

The serial-in node reads data from a serial (UART) port. It connects to devices like Arduino boards, GPS receivers, RFID readers, and industrial controllers over RS-232, RS-485, or USB-to-serial adapters. Data is emitted as messages split by a configurable delimiter (default: newline).

Properties

Common Baud Rate Reference

Example: Read Arduino Sensor Data

Receive temperature and humidity readings from an Arduino board sending newline-delimited JSON over USB serial at 9600 baud.

// serial-in node configuration
{
  "port": "/dev/ttyACM0",
  "baudRate": 9600,
  "dataBits": 8,
  "stopBits": 1,
  "parity": "none"
}

// Arduino sends (Serial.println):
// {"temp":23.5,"humidity":65,"sensor":"dht22"}

// Output msg (one per line received):
{
  "payload": "{\"temp\":23.5,\"humidity\":65,\"sensor\":\"dht22\"}",
  "port": "/dev/ttyACM0",
  "_msgid": "ser001"
}

// Connect to a json-parser node to get:
// msg.payload = { temp: 23.5, humidity: 65, sensor: "dht22" }
// Then route to dashboard or database

Example: GPS NMEA Data Input

Read NMEA sentences from a GPS module connected via USB-to-serial adapter. GPS modules typically output at 4800 or 9600 baud with newline delimiters.

// serial-in node configuration
{
  "port": "/dev/ttyUSB0",
  "baudRate": 4800,
  "dataBits": 8,
  "stopBits": 1,
  "parity": "none"
}

// GPS module sends NMEA sentences:
// $GPGGA,123519,4807.038,N,01131.000,E,1,08,0.9,545.4,M,47.0,M,,*47
// $GPRMC,123519,A,4807.038,N,01131.000,E,022.4,084.4,230394,003.1,W*6A

// Output msg per sentence:
{
  "payload": "$GPGGA,123519,4807.038,N,01131.000,E,1,08,0.9,545.4,M,47.0,M,,*47",
  "port": "/dev/ttyUSB0",
  "_msgid": "ser002"
}

// Parse in a function node:
// const parts = msg.payload.split(',');
// if (parts[0] === '$GPGGA') {
//   msg.payload = {
//     lat: parseFloat(parts[2]),
//     lon: parseFloat(parts[4]),
//     altitude: parseFloat(parts[9]),
//     satellites: parseInt(parts[7])
//   };
// }

Example: Industrial RS-485 Sensor

Read data from an RS-485 industrial temperature sensor using even parity at 19200 baud.

// serial-in node configuration
{
  "port": "/dev/ttyUSB1",
  "baudRate": 19200,
  "dataBits": 8,
  "stopBits": 1,
  "parity": "even"
}

// RS-485 sensor responds with hex data:
// Binary frames split by timeout (no newline)

// Output msg:
{
  "payload": "",
  "port": "/dev/ttyUSB1",
  "_msgid": "ser003"
}

// Parse Modbus-style response in function node:
// const temp = msg.payload.readUInt16BE(3) / 10;
// msg.payload = { temperature: temp };

Common Use Cases