user58828: I'm using two circuits for my wireless head mouse project, one of them is a transmitter circuit with Arduino Pro Micro, HC05 Bluetooth module, Elechouse Voice Recognition Module V3.1, GY-521 module based on the MPU6050 sensor. The receiver circuit (Arduino Pro Micro + HC05 Bluetooth) will receive the sensor readings from the transmitter circuit. Both modules were powered by USB from the laptop initially. They worked fine. To make the transmitter circuit completely detached from the laptop, I used a 9V battery, and a voltage regulator of 5V. The receiver circuit was still c. I should mention that I was using voltage dividers for both of the transmitter, and receiver circuit's HC05 Bluetooth modules.
onnected to the laptop USB.
.
After using the voltage regulator, the module was working fine but suddenly the HC-05 burnt, led stopped working. Transmission failed. HC05 of the receiver module also burnt after 2 minutes. Why did this happen? What's the solution?
Circuit connection:
Hc05 connection same for transmitter & receiver circuit
HC05 Tx -> Arduino Rx
Hc 05 rx -> 2k ohm -> gnd
Hc05 rx -> 1k ohm -> hc05 tx
Hc05 vcc -> arduino 5v
Hc05 gnd -> arduino gnd
Voice Recognition Module tx -> arduino 8
Rx -> Arduino 9
Vcc- 5v
Gnd - gnd
Mpu6050 sda - Arduino 2
Scl- Arduino 3
Vcc - 5V
Gnd- Gnd
Voltage regulator connection:
The connection was 9V battery +ve to input, -ve to ground, output to Arduino 5V



user83070: Your voltage divider pins are backwards the HC05 RX pin needs the divider, not the TX pin.   Its tx would be 3.3v out and the arduino pin wouldn't care it would still work.
Most likely while you were testing before the HC05 was probably already slowly dying.
the HC05 has a very basic 3.3v regulator on board but only a little over 5V input can fry things.
I have always put 75-100ohm in series with the 5V in just in case.
Your circuit is basically good but the the RX/TX pins on the HC05 need reversing.
Analog V. regulators are fairly crude and will vary voltage some.
5.000v accuracy is never dead on. I have seen as high as 5.7V out and that would not be good.
Also the HC05 RX pin is receiving a 5V signal back, sourcing thru the HC05 chip.
Even the Arduino help site warns against 5V if it can be avoided.
from Arduino's site
https://create.arduino.cc/projecthub/electropeak/getting-started-with-hc-05-bluetooth-module-arduino-e0ca81
Sending Data to Arduino via Bluetooth
HC05 module has an internal 3.3v regulator and that is why you can connect it to 5v voltage. But we strongly recommend 3.3V voltage, since the logic of HC05 serial communication pins is 3.3V. Supplying 5V to the module can cause damage to the module.


58828: <p>I'm using two circuits for my wireless head mouse project, one of them is a transmitter circuit with Arduino Pro Micro, HC05 Bluetooth module, Elechouse Voice Recognition Module V3.1, GY-521 module based on the MPU6050 sensor. The receiver circuit (Arduino Pro Micro + HC05 Bluetooth) will receive the sensor readings from the transmitter circuit. Both modules were powered by USB from the laptop initially. They worked fine. To make the transmitter circuit completely detached from the laptop, I used a 9V battery, and a voltage regulator of 5V. The receiver circuit was still c. I should mention that I was using voltage dividers for both of the transmitter, and receiver circuit's HC05 Bluetooth modules.
onnected to the laptop USB.</p>
<p>.
After using the voltage regulator, the module was working fine but suddenly the HC-05 burnt, led stopped working. Transmission failed. HC05 of the receiver module also burnt after 2 minutes. Why did this happen? What's the solution?</p>
<p>Circuit connection:
Hc05 connection same for transmitter &amp; receiver circuit
HC05 Tx -&gt; Arduino Rx
Hc 05 rx -&gt; 2k ohm -&gt; gnd
Hc05 rx -&gt; 1k ohm -&gt; hc05 tx
Hc05 vcc -&gt; arduino 5v
Hc05 gnd -&gt; arduino gnd</p>
<p>Voice Recognition Module tx -&gt; arduino 8
Rx -&gt; Arduino 9
Vcc- 5v
Gnd - gnd</p>
<p>Mpu6050 sda - Arduino 2
Scl- Arduino 3
Vcc - 5V
Gnd- Gnd</p>
<p>Voltage regulator connection:
The connection was 9V battery +ve to input, -ve to ground, output to Arduino 5V</p>
<p><a href="https://i.stack.imgur.com/4R9Fx.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/4R9Fx.png" alt="receiver circuit" /></a></p>
<p><a href="https://i.stack.imgur.com/clZzK.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/clZzK.jpg" alt="Transmitter Circuit" /></a></p>
 83070: <p>Your voltage divider pins are backwards the HC05 RX pin needs the divider, not the TX pin.   Its tx would be 3.3v out and the arduino pin wouldn't care it would still work.</p>
<p>Most likely while you were testing before the HC05 was probably already slowly dying.</p>
<p>the HC05 has a very basic 3.3v regulator on board but only a little over 5V input can fry things.
I have always put 75-100ohm in series with the 5V in just in case.</p>
<p>Your circuit is basically good but the the RX/TX pins on the HC05 need reversing.
Analog V. regulators are fairly crude and will vary voltage some.</p>
<p>5.000v accuracy is never dead on. I have seen as high as 5.7V out and that would not be good.</p>
<p>Also the HC05 RX pin is receiving a 5V signal back, sourcing thru the HC05 chip.</p>
<p>Even the Arduino help site warns against 5V if it can be avoided.</p>
<p>from Arduino's site
<a href="https://create.arduino.cc/projecthub/electropeak/getting-started-with-hc-05-bluetooth-module-arduino-e0ca81" rel="nofollow noreferrer">https://create.arduino.cc/projecthub/electropeak/getting-started-with-hc-05-bluetooth-module-arduino-e0ca81</a></p>
<pre><code>Sending Data to Arduino via Bluetooth
HC05 module has an internal 3.3v regulator and that is why you can connect it to 5v voltage. But we strongly recommend 3.3V voltage, since the logic of HC05 serial communication pins is 3.3V. Supplying 5V to the module can cause damage to the module.
</code></pre>
