Hello,
I have got problems with my HC-05 bluetoothmodul.
I´ve got connected it just like it`s discribed in this manul (http://howtomechatronics.com/tutorials/arduino/arduino-and-hc-05-bluetooth-module-tutorial/) and i am also using the same code.
I think the modul works because it blinks rapidly( that means, according to the shop, "ready for connection"). But if i connect my phone via several bluetooth-apps the modul enters the at-mode and nothing happens. But i dont wont to enter the at-mode and cant leave it anymore.
Do you know what i am doing wrong or how i can fix this?
Felix317:
I think the modul works because it blinks rapidly( that means, according to the shop, "ready for connection")
This is correct. The flash rate is about 2Hz
But if i connect my phone via several bluetooth-apps the modul enters the at-mode and nothing happens. But i dont wont to enter the at-mode and cant leave it anymore.
You are right to not want to enter AT mode, but this cannot be correct. At mode can only be entered by operations at the Arduino end and no amount fiddling would get you into AT mode by using the phone. AT mode is indicated by a regular slow blink, about once every two secs. If LED is steady on or mostly off with occasional blink, you are actually connected, and the problem lies elsewhere.
The code is probably junk but, if you change the serial begin to
Serial.begin(9600);
it might work. HC-05s usually come set to 9600 by default, not 38400.
There may be some other problem, and you might find the following background notes useful
http://homepages.ihug.com.au/~npyner/Arduino/GUIDE_2BT.pdf
http://homepages.ihug.com.au/~npyner/Arduino/BT_2_WAY.ino
Thanks for your quick answer.
I set the baud rate at 9600 but i still got the same results.
I contacted the shop which baud rate my HC 05 has and what the different modes of blinking mean because first it flashes with 2hz and when i connect every 2 seconds twice.
When your test-program with the serial Monitor everything works, but if i use my phone the screen stays blank.
I am still reading your guide but it is pretty long 
Yes, it has grown over the years and I am trying to make it more concise.
It sounds like you have a ZS-040 board and you are doing everything right at the phone end. You also have the code working OK. The problem may therefore be in the Bluetooth <> Arduino connection, which is not guaranteed by a kosher phone<>Bluetooth connection. Check the pictures and wiring Rx>Tx and Tx>Rx
Meanwhile i have read your Guide till chaper 15, because after that seems to come the advanced stuff(please correct me on that, if i´m wrong).
I am sure that the connection and the baud rate is fine, but is still not working properly. If i operate your program via my phone and press the resetbutton, the screen stays blank, while the serial monitor works.
I belive at least the TX(arduino)>RX(HC-05)connection is fine, and now comes the strange stuff, because if i operate your program via the serial monitor and type a word in, it also shows up on my phone(but only with on out of 5 differet apps).
But if i use my phone, nothing happens(with and without the serial monitor).
And the strangest thing is, that if i type in "hello", the hole word appears on my phone, but only the last letter on the serial monitor.
I think the problem is either with the TX (HC-05)> RX (arduino) connection, in the settings or the arduino(clone) itself, since I had already issues with the arduino.
Felix317:
Meanwhile i have read your Guide till chaper 15, because after that seems to come the advanced stuff(please correct me on that, if i´m wrong).
Section 15 should be quite far enough
I am sure that the connection and the baud rate is fine, but is still not working properly. If i operate your program via my phone and press the resetbutton, the screen stays blank, while the serial monitor works.
That is because you have broken the bluetooth connection, and need to reconnect using the phone.
I belive at least the TX(arduino)>RX(HC-05)connection is fine, and now comes the strange stuff, because if i operate your program via the serial monitor and type a word in, it also shows up on my phone(but only with on out of 5 differet apps).
But if i use my phone, nothing happens(with and without the serial monitor).
I'm finding it very hard to guess what is going on but, if you get ANYTHING showing up where is supposed to, the wiring must be OK, or at worst, was OK at that particular moment. If you are using a cheapo breadboard, now is the time to get suss about it.
And the strangest thing is, that if i type in "hello", the hole word appears on my phone, but only the last letter on the serial monitor.
Now that is really weird. I assume the typing you refer to is on the phone. There should never be any doubt about the PC connection. While my project was about working between Arduino and phone, and it has been said that you cannot share the serial monitor and bluetooth on hardware serial, my own experience is that it is quite OK to share provided that the monitor is only used to see what is going on, i.e. no use of PC keyboard. I could be wrong about that, and this may be subject to PC hardware or something.
I think the problem is either with the TX (HC-05)> RX (arduino) connection, in the settings or the arduino(clone) itself, since I had already issues with the arduino.
I would be more inclined to suspect wiring than hardware.
I dont think, that i break the connection when i reset, because the led on the HC-05 is still blinking the same way, as before and i can still recieve the text, that i write in the serial monitor.
I checked that every connection works and rewired it.
I can imagine how hard it must be for you to guess whats going, but trust me, its just as confusing as you imagine it. And when its my english, i am trying my best, but i´am a fifteen year old from germany and as you know "essen wir lieber Schnitzel und trinken Bier"
(put it in google translate)
Yes, its just as weird as its sounnds like. I did type the everything with the serial monitor. I also left the serial monitor and even changed the com port to make sure, that they dont interfere with each other. Same results.
And when i try it with my original Arduino UNO, the text
"OK then, you first, say something.....
Go on, type something in the space above
and hit Send or Enter,
then I will repeat it!"
appears on my phone, but it wont respond, when i type something. When i use the serial monitor and even unplug the HC-05 it shows the text and dosent respond too.
So weird... Every arduino and app behave completly different.
I am trying to get this hole projekt runnig since friday. 24/7. And i still have to deal with some 433Mhz transmitters/recievers and a second HC-05. >:(
Thank you for your help. Without you i woudn´t even know where to look for problems
The strange thing is, that i get with every board and app different results. On a few apps nothing shows upp, on others i can see what i wrote with the serial monitor. With the original arduino at least the start text shows up. But it dosent matters which combination of apps, boards or wireing i try, i never get it to repeat what i wrote with my phone. I also tryed my second HC-05.
I´ll probably just buy two other HC-05 from another retailer.
OK, but I can't help feeling that the problem is somewhere else and fixable. Having two faulty HC-0x and both the same fault, i.e. one-way traffic only, seems too much of a coincidence.
Check the Arduino Tx to ensure the wire is continuous, no dry joints in the divider etc.
I soldert the entire wireing together to make sure everything gets good contact. But this did not work either.
But this dosen´t matters anymore because i already bought an ESP 8266. I am quiet happy with that decision because i am building a smart home system and now i can access it from anywhere in the world.
I hope i wont run into similar problems with that device. Otherwise you will hear from me on saturday. 