Review on HiLetgo Bluetooth Wireless Compatible Arduino by Matthew Carr

Update! I bought two of these to wirelessly connect two Arduinos and they work for me. Both AT-09 Bluetooth modules work fine in slave mode, but it took me a while to set up one of them as a master. It's difficult because I didn't find any documentation for this particular module and the AT commands are different from what I found online. It's like a jigsaw puzzle where you have to guess what the pieces are made of - really fun! Magic AT commands: AT+Role11 to switch to master, AT+INQ? to find the address of the slave, and AT+CONN11 to connect to it. I don't know why you need the extra 1 at the end, but this seems to work. For your health!