No announcement yet.

Streaming data through RS232 expansion board

  • Filter
  • Time
  • Show
Clear All
new posts

  • Streaming data through RS232 expansion board

    Good Morning
    I am new to Arduino and PHPoC. I am using an Arduino Uno and the Arduino - RS-232 Expansion Board example to support a test of equipment that converts serial data to IP, multiplexes it and sends it through a Serial tunnel to a receiving station that reverses the process. I have putty connected to the USB to serial COM port and am monitoring the Arduino using serial com port output. Everything works fine and I seem to gave a good data connection through my tunnel.

    What I am looking for now is a way to simulate my production systems which send repeated data with a two second pause. I would like to do this without having to manually type something into the putty connection.

    I connected a DHT 11 and it shows the weather data on the Arduino serial monitor screen but only after I hit a key on the Putty screen. I am also not sure if that data is actually passing through the tunnel or if it is just being generated locally when the rs232 stream initiates.

    Could I just connect the dht data output to one of the 232 data input pins and pipe that through the connection?

    The code I used is

    // Arduino Example for RS-232 Expansion Board (PES-2606)
    // PES-2606 is an easy-to-use RS-232 expansion board for Arduino Uno and Mega,
    // which allows Arduino to exchanging data with serial device via RS-232.
    // This is an Arduino example that receive data from a serial device, send back
    // the serial device via RS-232 and print the data to serial monitor.
    // Arduino communicates with RS-232 expansion board through PHPoC [WiFi] Shield
    // using pins 10, 11, 12 and 13 on the Uno, and pins 10, 50, 51 and 52 on the
    // Mega. Therefore, these pins CANNOT be used for general I/O.
    // This example code was written by Sollae Systems. It is released into the
    // public domain.
    // Tutorial for the example is available here:

    #include <Phpoc.h>
    #include <PhpocExpansion.h>
    #include <DHT.h>

    // size of application buffer, reduce it if memory of Arduino is not enough
    #define BUFFER_SIZE 100

    byte expansionId = 1;

    ExpansionSerial rs232(expansionId);

    // application buffer
    byte rwbuf[BUFFER_SIZE];

    #define DHTPIN 2 // what pin we're connected to
    #define DHTTYPE DHT11 // DHT11

    DHT dht(DHTPIN, DHTTYPE); // Initialize DHT sensor for normal 16mhz Arduino

    float hum; //Stores humidity value
    float temp; //Stores temperature value

    void setup() {

    // initialize PHPoC [WiFi] Shield
    Phpoc.begin(PF_LOG_SPI | PF_LOG_NET);

    // initialize expansion board

    // get name and print it to serial

    // set baudrate, parity, data bit, stop bit and flow control to 9600, none,
    // 8 bit, 1 bit and no flow control, respectively.

    Serial.println("DHT11 sensor testing");

    //Initialize the DHT sensor


    void loop() {
    // get the size of the received data in the receiving buffer of RS-232
    // expansion board
    int rxlen = rs232.available();

    if(rxlen > 0) {
    // read and write length
    int rwlen;

    // get the size of free space in the sending buffer of RS-232 expansion
    // board
    int txfree = rs232.availableForWrite();

    // check to make sure that read data does not exceed size of application
    // buffer
    rwlen = min(rxlen, BUFFER_SIZE);

    // check to make sure that write data does not exceed free space in the
    // sending buffer of RS-232 expansion board
    rwlen = min(rwlen, txfree);

    // receive data from the receiving buffer of RS-232 expansion board and save
    // it to the application buffer
    rwlen = rs232.readBytes(rwbuf, rwlen);

    // send data from the application buffer to the sending buffer of RS-232
    // expansion board
    rs232.write(rwbuf, rwlen);

    // print data to serial monitor of Arduino IDE
    Serial.write(rwbuf, rwlen);

    float converted = 0.00;

    //Read data and store it to variables hum and temp
    hum = dht.readHumidity();
    temp= dht.readTemperature();

    Serial.print("Celsius = ");
    Serial.println(" C");

    //T(°F) = T(°C) × 9/5 + 32
    converted = ( temp * 1.8 ) + 32;
    Serial.print("Fahrenheit = ");
    Serial.println(" F");

    //T(K) = T(°C) + 273.15
    converted = temp + 273.15;
    Serial.print("Kelvin = ");
    Serial.println(" K");

    //T(°R) = (T(°C) + 273.15) × 9/5
    converted = temp + 273.15;
    converted = (converted * 1.8);
    Serial.print("Rankin = ");
    Serial.println(" R");

    Serial.print("Humidity = ");

    //2000mS delay between reads

  • #2
    Firstly, the reason why the data is only shown in the Serial Monitor when a key is hit is that: you put Serial,print() code inside: if (rxlen > 0) {.

    Could I just connect the dht data output to one of the 232 data input pins and pipe that through the connection?
    You can not connect DHT data output to RS-232 pin. They do not use the same protocol.