I hit AT and it sends back OK before I can add the plus and baud rate.
When does the baud rate actually change?
The JY-MCU module will only accept AT commands while not paired via Bluetooth, which means you have to send commands over the RX and TX pins of the module. 1. Use this code to create two serial ports on your Arduino and connect the JY-MCU RX to pin 3 and TX to pin 2. http://arduino.cc/hu/Reference/SoftwareSerialYou have to change the line that says Code: [Select]mySerial.begin(4800); to Code: [Select]mySerial.begin(38400);because the JY-MCU defaults to this baud rate. Open your Arduino serial monitor and set it to 57600. You should see "Goodnight moon!"2. You should now be able to send "AT" and it should reply "OK". You can also pair with your computer bluetooth or phone bluetooth and anything you type in the serial monitor should now show up on your computer bluetooth or phone, but AT commands will not work while bluetooth is paired. If you get strange characters instead of "Goodnight moon!", your baud rate is not set correctly. 3. To change the baud rate, refer to this webpage: http://byron76.blogspot.com/2011/09/one-board-several-firmwares.htmlIn this case you want to send the command "AT+BAUD8", which should give a reply "OK115200". If it does not reply like that then you did not change anything. Good luck.
That means you have the Arduino -> PC set up correctly, but the JY-MCU -> Arduino is not set up correctly. Check the baud rate and the RX/TX lines again. Try using the JY-MCU board in bluetooth mode to know that it works at the baud rate you expect.
Alright that's good that you got it communicating with you with AT commands. In my case when I sent AT+VERSION I got "linvor 1.5". If you get the version working then this might be different. Did you try the AT commands without the plus, like "ATVERSION"?