     Serial.println("Logobot");
     bot.begin();
     nfc.begin();
+    nfc.setPassiveActivationRetries(1);
     nfc.SAMConfig();
     bot.enableLookAhead(true);
     bot.initBumpers(SWITCH_FL_PIN, SWITCH_FR_PIN, SWITCH_BL_PIN, SWITCH_BR_PIN, handleCollision);

    nfc.PrintHex(uid, uidLength);
    Serial.println("");   
  }
  return uid;
}

static void handleCollision(byte collisionData)

#include <Servo.h>
#include <Wire.h>
#include <SPI.h>
#include <dmtimer.h>
#include <Adafruit_PN532.h>

Bot bot(MOTOR_L_PIN_1, MOTOR_L_PIN_2, MOTOR_L_PIN_3, MOTOR_L_PIN_4, MOTOR_R_PIN_1, MOTOR_R_PIN_2, MOTOR_R_PIN_3, MOTOR_R_PIN_4);
String cmd; // cmd received over serial - builds up char at a time
Adafruit_PN532 nfc(PN532_SCK, PN532_MISO, PN532_MOSI, PN532_SS);
DMTimer checkTimer(2000000);
String cardval;
String oldcardval = "";
bool bot_drive = 1;

void setup()
{
