Fried the bluetooth module(JY-MCU V1.02),can I use the STATE PIN as Vcc and work

I fried the bluetooth module in a stupid attempt to power my arduino externally with a voltage power supply.Voltage was 9V but I guess the amps went above than 500mA.Somehow,this fried my bluetooth moduel(JY-MCU) and the lights have stopped flickering and the comp. doesn't detect him anymore. :(

Is there anyway I can feed 3.3V to the bluetooth module via the STATE PIN and make it work? This I ask because when I give 5V to the state pin,the LED glows continuously. Maybe all that got fried was the VCC pin?Tips anyone?

If you fried your module, it's gone. Providing power to the state pin may activate the onboard LED but that doesn't mean the module is powered and working correctly. You cannot fry a pin, you fry at least a complete part of the circuit inside the chip. If that part was the power supply part you'll have to buy a new module. Fortunately you just fried one of the ultra-cheap BT modules so getting a replacement is not that expensive.

Would you then suggest buying a HC-06 or a HC-05? In my project,the Bluetooth module is just needed to transfer serial data from the Arduino to the PC, not the other way round i.e I’m never sending anything from the PC. Does this mean my Bluetooth module is a slave/would one define it as a master?

I’ve read in forums that HC-05 can act both as a master and a slave,as compared to the HC-06 which acts like a slave all the time. The odd thing is that HC-05 is 3 Euros cheaper.

Naming conventions for these devices are blase (blaa zay) , i.e. mean nothing. If you have the radio board without adapter it requires 3.3v. Else if you have a radio with adapter board check to see if there is a smd voltage regulator, if so, this board takes 5v from the bt vcc pin. Newer boards have 3.3v & 5v pin. Any of these bt boards that accepts 5v is usually only tolerable up to 5.3-5.8v without adequate cooling on the regulator, because the radio is 3.3v.

Connect 5v to vcc if permitted as above & gnd, does it blink? If it does it still works, if it doesn't you may have killed the regulator or the led or both.

You should also check the device using

If all else fails there's a 99% chance the bt device is deceased :(

Would you then suggest buying a HC-06 or a HC-05?

Both are essentially the same hardware with just other firmware on it and the most annoying thing is that a HC-06 is not necessarily equal to another HC-06 because there the firmware may differ also. In your case a slave-only device is enough so you may buy any device that fulfills your other needs.


Which essentially is the HC-05 radio with full firmware, with 5v & 3.3v base adapter, relatively pricier though.

16 bit PSWD

AT+PSWD=r3a11yhard2gu355 :slight_smile:


So,as a novice,what I understand from the word "firmware" is that they are of 2 types :1.Linvor 2.HC-05 and these define the type of the bluetooth module.Am I correct?

My other question is about the version number in these slave boards. Does it really matter which version I buy? There's a new one available on ebay called HC-06 V2.0. I've had great results with V1.2 but no one sells that version anymore.

So,as a novice,what I understand from the word "firmware" is that they are of 2 types :1.Linvor 2.HC-05 and these define the type of the bluetooth module.Am I correct?

No, as far as I understood it, HC-05 and HC-06 are both the same hardware, just different firmware. And both types are available in a variety of different versions with just more or less the same functionality. I just experimented with one version of HC-06 but I can tell from my experience, that some of the documentation for that module found online didn't match my module, so there really seem to be different versions out in the wild named the same.

Thanks for the help everyone.Bought a HC-06.Hope not to fry it again.

LC Technology

The closely translated english name, IS the original board manafacturer.

Originally sold as a bare radio with minimal firmware, then updated the eeprom & re-released with newer firmware.

They designed the radio for government applications with full firmware.
Many years later selling to the general public blank radios & heavily modified (stripped) firmware.



is a near match to military class, except they have removed Pipe-lining functionality, yet kept the checksum & encoding algorithms on the current firmware.

For a full pledged BT radio, i re-iterate to anyone, get the