/*
Barcode Scanner
This code reads the input from a ps/2 keyboard or keyboard-like
device (e.g. a barcode scanner), translates the scan-codes into
numbers (only numbers from 0 to 9 can be used at the moment)
It is nowhere near a complete implementation of the ps/2 protocol,
but it should give you a starting point.
mys .// Benjamin Maus
( benjamin.maus <at> allesblinkt.com )
2007
*/
char *goodCards = { "3455192327218", "4005209057240", "5060048310337" };
int SCAN_ENTER = 0x5a; int SCAN_BREAK = 0xf0;
int breakActive = 0;
int clockPin = 3; // Clock is only output.
int dataPin = 2; // The data pin is bi-directional
// But at the moment we are only interested in receiving
int ledPin = 13; // When a SCAN_ENTER scancode is received the LED blink
int clockValue = 0; byte dataValue;
byte scanCodes[10] = {0x45,0x16,0x1e,0x26,0x25,0x2e,0x36,0x3d,0x3e,0x46}; char characters[10] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9'};
int quantityCodes = 10;
char buffer[64] = {};
// This saves the characters (for now only numbers)
int bufferPos = 0;
int bufferLength = 64;
After this:
void setup() {
pinMode(dataPin, INPUT);
pinMode(clockPin, INPUT);
pinMode(ledPin, OUTPUT);
Serial.begin(9600);
}
void loop() {
dataValue = dataRead();
// If there is a break code, skip the next byte
if (dataValue == SCAN_BREAK) {
breakActive = 1;
}
// Translate the scan codes to numbers
// If there is a match, store it to the buffer
for (int i = 0; i < quantityCodes; i++) {
byte temp = scanCodes[i];
if(temp == dataValue){
if(!breakActive == 1){
buffer[bufferPos] = characters[i];
bufferPos++;
}
}
}
//Serial.print('*'); // Output an asterix for every byte
// Print the buffer if SCAN_ENTER is pressed.
if(dataValue == SCAN_ENTER){
Serial.print("\nbuffer: ");
// Read the buffer
int goodMatch = -1;
for(int c=0; c<cardCnt; c++)
{
if(strcmp(buffer, goodCards[c]) == 0)
{
goodMatch = c;
break;
}
}
Serial.print("goodMatch = ");
Serial.println(goodMatch); // Will print index of good card in array
int i=0;
if (buffer[i] != 0) {
while(buffer[i] != 0) {
Serial.print( buffer[i] );
buffer[i] = 0;
i++;
}
}
Serial.println(" [Enter]");
bufferPos = 0;
// Blink the LED
digitalWrite(ledPin, HIGH);
delay(300);
digitalWrite(ledPin, LOW);
}
int goodMatch = -1;
for(int c=0; c<cardCnt; c++)
{
if(strcmp(buffer, goodCards[c]) == 0)
{
goodMatch = c;
break;
}
}
Serial.print("goodMatch = ");
Serial.println(goodMatch); // Will print index of good card in array// Reset the SCAN_BREAK state if the byte was a normal one
if(dataValue != SCAN_BREAK){
breakActive = 0;
}
dataValue = 0;
}
int dataRead() {
byte val = 0;
// Skip start state and start bit
while (digitalRead(clockPin)); // Wait for LOW.
// clock is high when idle
while (!digitalRead(clockPin)); // Wait for HIGH.
while (digitalRead(clockPin)); // Wait for LOW.
for (int offset = 0; offset < 8; offset++) {
while (digitalRead(clockPin)); // Wait for LOW
val |= digitalRead(dataPin) << offset; // Add to byte
while (!digitalRead(clockPin)); // Wait for HIGH
}
// Skipping parity and stop bits down here.
while (digitalRead(clockPin)); // Wait for LOW.
while (!digitalRead(clockPin)); // Wait for HIGH.
while (digitalRead(clockPin)); // Wait for LOW.
while (!digitalRead(clockPin)); // Wait for HIGH.
return val;
}
