Bluetooth modules are available in numerous variety in the market (HC05 and HM10/AT09) . Thus, many time you end up debug your Bluetooth module or the circuit. There are few reasons why this happen:
We will tell you how to identify these issues and debug them.
There is a quick test to check your Bluetooth module. Upload evive Firmware using Arduino IDE or Scratch (whichever you are comfortable with). Plug your Bluetooth module on evive Bluetooth slot as shown in the figure below:
Turn ON evive. You will observe a menu pop-out on the TFT Display:
Serial Monitor: Serial Monitor allows the user to select the serial (evive has four serial channel) and also allows users to set the baud rate at which they want to open the serial port. It, then, reads and displays the data coming from the selected serial at specified baud rate by the user.
If the baud rate if the Bluetooth is set wrong you get garbage message on the serial monitor. Thus we will change the baud rate of the Bluetooth module using AT Commands.
Thus if you are using a different baud rate to communicate, garbage data will come. Hence, either change the baud rate specified in the program to the above number or change the module baud rate.
To change the bluetooth module baud rate, use this command: AT+UART=115200,0,0
You will get OK message. To check if the baud rate has changed or not, repeat Step 3.
Line end settings specifies how the string is terminated that you send to your evive/Arduino board after clicking the Send Button.
The right setting depends on how your sketch handles the incoming characters.
Line end characters are a convenient and common way of indicating your board the end of a transmission.
Choose the appropriate the line ending setting.
Due to some design issue, some boards have problem while using Bluetooth module though its dedicated slot.
This circuit will work of every Bluetooth. If not, the Bluetooth module might be faulty.
If you still have problem, post it on the forum.