5PCS HC-05 Wireless Bluetooth Receiver RF Serial Transceiver Module Master Slave Integrated Bluetooth Module 6 Pin Wireless Serial Port Communication BT Module

This set of Bluetooth modules is a great set for anyone who wants to learn how they work. I would highly recommend.

script to write device name./** David Dold* JDDL Design, LLC** HC-06 differs from an HC-05. HC-06 are slave only devices, whereas HC-05 can be master or slave.* By default, no BT connection, an HC-06 device in AT mode @ 9600 baud between** An HC-06 does not respond to "AT"** The response from an HC-06 device for "AT+NAMEwhatever" is OKsetname** LEDs flashing on the HC-06 indicate command mode, steady indicate a BT connection.** NOTE: If you maintain a BT connection, via a terminal session or mobile app, then the AT commands* will simply transmit to the connected device.** The HC-06 spoc sheet calls for divided resistors and RX, I've never done it...** TROUBLESHOOTING* If you are unable to get this to work, confirm your rx/tx pins are correct. Confirm your wiring with a Serial BT Terminal.* On Android there are many to choose from. Pair your HC-06 with your phone, then connect to the device via the BT terminal app,* LEDs on HC-06 go solid. Run this sketch. Characters sent from the send textbox via the serial monitor or sent from the app,* echo on the opposing device. If your characters do not appear, re-check your wiring (hint is tx/rx reversed?).** If you are using seperate power supplies for your Arduino device -and- the HC-06, the grounds must be bonded.** Setting baud rate is for the hardware connection between* processor pid and the HC-06 device. BT connection is negotiated* between radios.*/#include <SoftwareSerial.h>#define BLUETOOTH_TX 10#define BLUETOOTH_RX 9#define BAUDRATE 9600SoftwareSerial bluetooth(BLUETOOTH_RX, BLUETOOTH_TX);void setup(){Serial.begin(BAUDRATE);Serial.println("ready");pinMode(BLUETOOTH_RX, INPUT);pinMode(BLUETOOTH_TX, OUTPUT);//setup bluetoothbluetooth.begin(BAUDRATE);bluetooth.flush();delay(1000);bluetooth.write("AT+NAMELifeMCP");}void loop(){//optionally, send characters via the SerialMonitor, this can be commented out and the bluetooth.write in setup() works.//outbound to HC-06if(Serial.available()){Serial.println("writing to bt");while (Serial.available())bluetooth.write(char(Serial.read()));}//inbound from HC-O6if(bluetooth.available()){Serial.println("BT Response");while (bluetooth.available()){delay(3);Serial.print((char)bluetooth.read());}Serial.println();}}

I'm using this with an arduino to communicate with an OBD2 ELM327 in my car. The older HC-05 I used were version 2.0. These are version 5.0. The big difference for me is that the older HC-05 required an '$' to be prepended to commands intended to be passed-through to the ELM327. But the newer version 5.0 HC-05 units do not require it and just pass-through everything.The other issue Im working is that these newer units don't like the AT-INIT command for some reason. More later...

These are the master versions allowing connections to your Arduino projects. HC-06 is the Slave version. These all work as advertised and are easy to add to your project. Don't forget the passwords for base module is "1234"

The failure rate of these is about 90%. They power up and then die shortly thereafter. I have been using the HC-05 and HC-06 modules for 9 years now on a production basis and have never seen such a failure rate. Obviously there is a quality control issue with this supplier. The packaging was also different with this purchase.Perhaps it is a new firmware issue. These models report a HC-06-2021910 version after the AT+VERSION command.I will keep hunting for documentation of this firmware, but for now these modules are fails.

Out of 5 units, 1 was DOA, 1 had burned out LED, and 4 don't work much below 4 volts.Returned.Also, CSR chip is much smaller than typical HC-05.Incidentally, FW version is: 5.0-20220104

I was pleasantly surprised with how easy these were to use. I appreciate that the pins are labeled on the back of the circuit board. Be aware that there are 2 different voltages. Make sure to use a couple of resistors to get the voltage right. This will prolong the life of the module. Glad I bought a 5 pack. I will be using these on more projects.

Work better than the H05!