Hardware troubleshooting a HC-05 Bluetooth module

For the past week i have been using this HC-05 module with no problems.

Now i don't know what i have done but i can no longer connect to it.
(Connecting via a Bluetooth Terminal app. on Android phone keeps failing)

FWIW : the "event" that preceded this communication failure was running a program that inadvertently looped through a println multiple times with "no available display resource" - i could sense the Bluetooth Terminal app. starting to seize - incoming "data flood" (???) and it hanged several times meaning i was unable to input a key/char (to send to the Arduino).

Also - i had a LED voltage indicator on the power-rails and i now remember, it spiked to 5.01 V while the app seized. Then again, it's possible it was just the motors drawing current incessantly - it's basically a BT-remote controlling a vehicle via 'w,s,a,d'.

Don't know whether it's possible the HC-05 module got fried - but the LED is still blinking waiting for pairing and it is a detectable device - just "unconnectable".

Can anyone suggest what steps to take to find out what has gone wrong ?

BabyGeezer:
Don't know whether it's possible the HC-05 module got fried .

If there is nothing to suggest that Arduino is fried, and the wiring to Bluetooth is correct and unchanged, and your phone is kosher, it probably has

Nick_Pyner:
If there is nothing to suggest that Arduino is fried, and the wiring to Bluetooth is correct and unchanged, and your phone is kosher, it probably has

well, that's sad to hear. :frowning:

so, what i described as the "event" is theoretically possible ?
and that it wasn't making up some scenario from dodgy electronics knowledge ?

even if it's fried, it can still run the indicator LEDs ?
is there really no other tinkering i could do just to be sure before trashing it ?

Nothing you describe sounds fatal to bluetooth, hence my comment.
I suppose "two weeks......with no problems" could mean that you now have flat batteries, but HC-05 can run on 3.6v so I doubt the problem lies there.

Your first, last, and most obvious test is to run a hello programme, with a known good phone, with Arduino out of the car, with everything else disconnected, and using a proper wall wart for power.

looks like i have to get a new one then :frowning:

i tried the most basic ;

void setup() {
	Serial.begin(9600);
}

void loop() {
        digitalWrite(13,HIGH);
        Serial.println("Hello world!");
        digitalWrite(13,LOW);
	delay(2000);
}

with every thing disconnected but the RX0,TX1 and a known power source.

i haven't verified the phone though - that can Receive a file from the PC, but this new Windows doesn't have the old HyperTerminal to test Serial communication and i can't get it to lock on to a COM port for the Bluetooth dongle. (which means i can't use the PC to test the HC-05 either !)

talk about barebones hardware...

thanks for all your input then.

Cheers.

BabyGeezer:
Windows doesn't have the old HyperTerminal

RealTerm should suffice

Nick_Pyner:
RealTerm should suffice

Thanks, will give that a go.