Teensy 4.1 and HC-05

[RobotMan]

Hi everyone,

I am pretty new to teensy and I just tried to connect my teensy 4.1 to an HC-05 to connect it to my android. I am using the app "Arduino BlueControl." I connected RX to pin 7 and TX to pin 8 (I also tried the reverse), but I am getting no response on the app terminal. Here is my test code. Any help would be appreciated.

Yehuda Tager

void setup() {
Serial2.begin(9600);
}

void loop() {
Serial2.println("hello");
delay(100);
}

[PaulS]

Hi Yehuda,
Just checked your code on a Teensy 4.1 & HC-05 module and it is working fine.
Teensy pin 7 connects to HC-05 pin TXD, pin 8 to pin RXD.
Do you power the HC-05 by 3V3 like I did? And did you pair it?
Does the LED flash on your HC-05 module?

Here is my setup and Android terminal program output:





Paul

[RobotMan]

Thanks so much for helping me out. Yes I did power the HC-05 with 3.3 volts (from the output of the teensy, so it should be regulated nicely). The light was blinking with 2 quick flashes, then a pause. What does pair it mean? The app on the phone did say that it was connected to HC-05.

[PaulS]

With pair I meant Bluetooth pairing. But you did that obviously.
The 2 quick flashes are shown when a program connects to the HC-05 module.
Perhaps you should try the app I used? Serial Bluetooth Terminal

Paul

[RobotMan]

It is working now. Thank you so much for your help.