First of all, your void loop isn’t Blynk friendly. You should read this:
http://help.blynk.cc/getting-started-library-auth-token-code-examples/blynk-basics/keep-your-void-loop-clean
Secondly, Bluetooth isn’t really the best way to go with Blynk. Not all Blynk functions work with Bluetooth, because there is no direct connection from the Arduino to the Blynk server.
Thirdly, moving to an Arduino Mega would make your life so much easier, as you have more pins and multiple UARTs. An ESP-32, or multiple ESP8266’s with Bridge code would be a better solution if you want to use Wi-Fi.
Moving on to your specific questions (but out of order)…
It’s not just that you can’t have the USB plugged-in, it’s that the Serial UART cant handle data destined for both the HC-05 and the serial monitor, it’s one or the other.
This…
[quote="quebecois_sti, post:1, topic:38037"]
DebugSerial.begin(9600); DebugSerial.println("Waiting for connections...");
[/quote]
isn’t allowed because the Serial UART will be used by the HC-01, which means that there will be NO debug output available (tricky for debugging - see my Mega recommendation).
These two are related…
The baud rate on pins 0,1 is whatever you declare it as in your Serial.begin command. However, the Uno and the HC-05 need to be talking at the same baud rate for them to be able to understand each other. You need to temporarily use the Arduino in “AT mode” to do this, or use an FTDI adapter to connect your HC-05 to your PC and issue the AT commands to set the baud rate.
The Arduino uses 5v logic levels on these pins, so all is good.
In the app you should use virtual pins rather than directly manipulating the GPIO pins on the Arduino, it gives you much more control. Also, you’ll need to update the app widget statuses when you receive an RF command, so that the two stay in sync.
If you’re going to create a smarthome system then you’ll quickly move away from Bluetooth to Wi-Fi and may find that moving to a Node-Red and MQTT system along with Blynk is the best way to go.
Pete.