Connect the Bluetooth Module - BLUETOOTH APP INVENTOR - AGTECH

1. Connect the 4 jumper wires to the 4 middle prongs on the Bluetooth module (VCC, GND, TXD, and RXD)
2. Connect the wire attached to VCC on the Bluetooth module to 5V on the Arduino.
3. Connect the wire attached to GND on the Bluetooth module to GND on the Arduino.
4. Connect the wire attached to TXD on the Bluetooth module to Pin 0 (RX) on the Arduino.
5. Connect the wire attached to RXD on the Bluetooth module to Pin 1 (TX) on the Arduino.

STEM Connections

Pins 0 and 1 on the Arduino (RX and TX, respectively) are for communication between the Arduino and other devices. This includes the Bluetooth device connected, as well as the computer connected by the USB cable.  When another device is connected to pins 0 and 1, the ability to communicate with the computer is lost.  Therefore, any changes made to the Arduino code is not uploaded, and the Arduino is not able to communicate with the computer while the device is connected to pins 0 and 1. If you want to upload new code, first disconnect the wires from 0 and 1, upload the code, and reconnect the wires only after the code is done uploading. 

Alternatively, you could modify the code to connect the Bluetooth module via different pins. You must use PWM~ pins, for example, 10 and 11 which is an easy change from 0 and 1. To make this change in the code, edit the line that says “SoftwareSerial BTConnect(0, 1);” to “SoftwareSerial BTConnect(10, 11);”.  Please note that 0 and 1 were selected because of their ease of use. If you want to create 2-way communication between the Android device and the Arduino, it is recommended to use pins 0 and 1 for the Bluetooth connection.

If you are using jumper wires as we recommend, students may have some difficulty with the difference in colors between their wires and your wires or the wires in the video. Be sure to emphasize that wires do not carry a charge until they are connected. We typically use red to signify positive power and black to signify negative power. However, in this case, we are using the colors connected to the Bluetooth module.  Asking students to write the colors connected to the 4 connections on the Bluetooth module in their notes might help with clarification.

If you are using the Thinkabit Lab notebook have students complete the following:

VCC: (color) to 5V

GND: (color) to GND

TXD: (color) to Pin 0 (RX)

RXD: (color) to Pin 1 (TX)

1. Don’t have jumper wires

• Place the Bluetooth module in the breadboard at the opposite end from the colored rows, being sure to place each connection in a different row.
• Get 4 more wires, 1 red, 1 black, and 2 white.
  • Connect the red wire from the row of the breadboard where VCC is connected to 5V on the Arduino.
  • Connect the black wire from the row of the breadboard where GND is connected to GND on the Arduino.
  • Connect one white wire from the row of the breadboard where TXD is connected to Pin 0 (RX) on the Arduino.
  • Connect the other white wire from the row of the breadboard where RXD is connected to Pin 1 (TX) on the Arduino.

2. There’s a wire stuck in Vin/GND/Pin 0/1

• An instructor or adult can use a box cutter or pliers to remove the wire
• Or, replace the Arduino

3. Wire doesn't have enough exposed metal to connect to the Arduino or breadboard

• An instructor or adult can use the wire cutters to strip the plastic coating off the end of the wire