Bluetooth Module not connecting to App but connected to phone - help!

cattledog:

 mySerial.begin(38400); //Serial communcation for Aircasting Application

You are not using an AirCasting module. The default data transmission mode baud rate for the HC 05 is 9600 baud. Have you have gone into AT mode and changed it? If not, set the software serial baud rate to 9600.

You really should be working with a standard BT terminal app on yuour phone instead of something you put together. I use the Serial Bluetooth Terminal app from Kai Morich https://play.google.com/store/apps/details?id=de.kai_morich.serial_bluetooth_terminal&hl=en_US

I need to make an app because the BT module is connected to a gas sensor. I'm making an air pollution-detecting device.

I think the main problem is that OP still doesn't understand the layout of a breadboard.
The image of post#6 (if I see it right) shows pin 10 and 11 and two wires of the BT module all connected (shorted) to the same spot on the breadboard. And the voltage divider connected to nothing.
No use trying to run any code as long as this is not fixed.
Leo..

I’m making an air pollution-detecting device.

That sounds great but is hardly the point, and using a standard bluetooth terminal is good advice. You need to be able to walk before you can run. At the moment, you haven’t the faintest idea of what you need to do to walk, and making an phone app has to be right at the bottom of the list of priorities. Using a standard terminal means you have something that works, at the moment the only thing, and enables you to address the real problem(s) - which you seem to be ignoring.

Wawa:
OP still doesn't understand the layout of a breadboard.
.............
No use trying to run any code as long as this is not fixed.

Fair enough, and he won't get a result on the phone until he gets Arduino to say something to it.

This brings me in today...

Don’t try to do everything at once.
Solve one problem at a time!

Rip out every wire, and make each piece of the puzzle work by itself without the distraction of the other bits!

Since comms is fundamental to your project, use the examples to work with your BT module, then put that aside and get other pieces working alone.

Finally glue them together.

lastchancename:
Don’t try to do everything at once.
Solve one problem at a time!

Indeed, and this childs' guide might be useful
http://homepages.ihug.com.au/~npyner/Arduino/GUIDE_2BT.pdf
http://homepages.ihug.com.au/~npyner/Arduino/BT_2_WAY.ino

Ok I took a look at again and it connected! I fixed the wiring. Now the problem is the code. I can’t seem to understand how to send the data from the code (see previous post) to the phone app. I’m so close to finishing too.

jkg9:
I can't seem to understand how to send the data from the code

Replies #1 (item 3), #10, #12, #13, #17, #25 might help

Alright then. I troubleshooted (or troubleshot) some more, and everything works now! Thank you everyone so much for helping me. I really couldn't have done it without you all. I'll come back if I have any more questions. Bye for now :slight_smile:

jkg9:
I fixed the wiring. Now the problem is the code.

You said that before, more than once, and it still wasn't right.
Post it, so we can check.
Leo..