Using Bluetooth wireless communications with the Launchpad is made easy by the HC-07 Bluetooth-to-Serial board. They are inexpensive (usually less than the Launchpad costs), and free you from needing a USB connection unless you are reprogramming the Launchpad's chip. With the HC-07 board, we can talk to the Launchpad wirelessly, from across the room or even farther.
The HC-07 board is a little thing, smaller than my smallest finger. It has 6 pins, but we will only be using the four inside pins.
The pins are power (VCC), ground (GND), serial transmit (TXD), and serial receive (RXD). The board can run on anything from 3.3 volts to 6 volts, so we will use the Launchpad's VCC, which is 3.3 volts.
We connect the Launchpad's Port 1 pin 1 to the HC-07's TXD pin, and the Launchpad's Port 1 Pin 2 to the HC-07's TXD pin. We connect power and ground, and the hardware is ready to use. It's that simple.
The board defaults to 9600 baud, just like the Launchpad does, so there is no configuration needed. We will run at faster speeds later, but for now, we will leave it in the default mode.
We'll start with a very simple program that simply prints a count to the serial port:
Now all we need to do is to connect to the Bluetooth device using our computer, cell phone, or tablet.
The photo above shows the Launchpad talking to a Nexus 7 tablet (and Android device made by Google). The program it is running is BlueTerm, a free terminal program that lets us send and receive characters over Bluetooth as if we were connected by wires.
On my Windows laptop computer, I simply connect to the HC-07 using the Bluetooth Devices page, and then use a terminal program such as Putty to connect to the COM port associated with the Bluetooth device we have connected to. In this case, it is COM25.
When connecting to the HC-07, the user is prompted for a PIN number. The default for the HC-07 is simply 1234.
Now that you know how to talk to the Launchpad using Bluetooth, you can control your sculpture, robot, or work of art from your cell phone.