Arduino --> printer (how)

This post is in response to a comment by Carl on an earlier post (see here).

The simplest method to interfacing an Arduino to a dot matrix printer is to use a BAS120 module or core chip (both of which can be bought at Microzed computers in Australia). These chips are designed to be used with Picaxe or Basic Stamp microcontrollers, but work fine with Arduino.

By setting the hardware serial speed of the Arduino to a baud rate of 2400, it is very easy to simply pass information onto the printer from, say, Max/MSP, using a serial interfacing protocol. This is because the printer module also runs at a baud rate of 2400.

It is then simply a matter of connecting the RX pin of the BAS120 module to the TX pin of the Arduino board.

There are a number of useful data byte to remember when using a printer. A '2' wakes the printer up so that it is ready to accept printing commands. A '3' puts the printer to sleep. A '10' followed by a '13' prints a carriage return followed by a line feed. In the case of the printer that has been featured in previous posts (Epson LQ 300), the '10,13' combination actually forced the printer to print. Some printers only start printing when they receive a page feed character (not just a line feed).

As one can see, the code below is very simple and offers no abstraction or symbolic conversion of any kind - all the printing data and manipulation has to occur from the computer end. But of course, it is possible to extend this code considerably such that the Arduino is doing more work.

Arduino Code

byte STX = 2;
byte data;

void setup() {
  Serial.begin(2400);
  Serial.print(STX);
  digitalWrite(1, HIGH);
  delay(5);
}

void loop() {
  if(Serial.available() > 0) {
    data = Serial.read();
    Serial.print(data);
  }
}