Debugging RN 42 HID Mouse I'm trying to use the RN 42 and Arduino Uno to control a bluetooth mouse. I configured the RN 42 with the commands S~,6 and SH,0220 and R,1 to put the device in HID mouse mode. Is there anything I missed? Below is the sketch I am using to send mouse reports to the bluetooth. The sketch compiles fine, but moving the joystick does not move the cursor. I included a line of code at the end to print on the serial port whatever data is being sent through software serial to the bluetooth. However when I view the serial monitor, I get back a lot of reversed question marks. Anyone know why this is? Thanks in advance.


const int bluetoothTx = 4;    // TX pin of RN-42, Arduino D2 (configure as RX pin of Ard)
const int bluetoothRx = 3;    // RX pin of RN-42, Arduino D3 (configure as TX pin)
const int button = 5;
const int xAxis = A0;         // joystick X axis
const int yAxis = A1;         // joystick Y axis
int range = 12;               // output range of X or Y movement
int responseDelay = 5;        // response delay of the mouse, in ms
int threshold = range / 4;    // resting threshold
int center = range / 2;       // resting position value

SoftwareSerial BT(bluetoothTx, bluetoothRx); // args SoftwareSerial(RXpin, TXpin)

void mouseCommand(byte buttons, byte x, byte y) {
  BT.write((byte)0xFD);
  BT.write((byte)0x05);
  BT.write((byte)0x02);
  BT.write((byte)buttons);
  BT.write((byte)x);
  BT.write((byte)y);
  BT.write((byte)0x00);
}


int readAxis(int thisAxis) {
  // read the analog input:
  int reading = analogRead(thisAxis);

  // map the reading from the analog input range to the output range:
  reading = map(reading, 0, 1023, 0, 12);

  /* threshold prevents the mouse from reading small unintentional movements. 
  If the output reading is outside from the rest position threshold, use it: */
  int distance = reading - center;

  if (abs(distance) &lt; threshold) {
    distance = 0;
  }

  // return the scaled distance for this axis:
  return distance;
}


void setup() {
  pinMode(button, INPUT);
  pinMode(bluetoothTx, INPUT); // bluetoothTX is equivalent to arduino RX pin
  pinMode(bluetoothRx, OUTPUT);
  Serial.begin(115200);  // Begin the serial monitor at 115200bps
  BT.begin(115200);  // RN-42 defaults to 115200bps
}

void loop() {
  // read and scale the two axes:
  int xReading = readAxis(xAxis);
  int yReading = readAxis(yAxis);
  int buttonState = digitalRead(button);

  // move the mouse:
  mouseCommand(buttonState, xReading, yReading);
  delay(responseDelay);

  if(BT.available())  // If there's data being sent to the bluetooth module
  {
    // Send any characters the bluetooth receives to the serial monitor
    Serial.print((char)BT.read());  
  }
}
The problem with getting no response from the mouse was that the bluetooth did not auto reconnect to the computer after powering down. I solved this by sending the command SM,6 for auto reconnect and then R,1 to reboot.