Adding Bluetooth To your Microcontroller projects

Bluetooth has become Ubiqutios these days Bluetooth Wireless technology is present is Most mobile phones today as well as in laptops and in desktop PCs.And If your PC or laptop doesn’t have it then you can get a Bluetooth USB dongle for cheap(like 2-3$ )!

Wouldn’t it be interesting if your mobile phones /PCs could talk to your Micro-controller Projects??

Lets find out how to add Bluetooth capability easily to your existing Micro-controller projects with out many hardware or software changes.

Bluetooth has many ‘profiles’ for communication with various kinds of devices.The profile in which we will be interested in is the Serial Port Profile or SPP for short.This profile simply emulates a standard Serial port over a wireless bluetooth link.

I was working on a arduino project and wanted to eliminate the wired connection to the arduino form my laptop.The laptop had a GUI running which sent data over a serial COM port to the arduino.I got a Bluetooth module from Lamington road,Mumbai for around 850 INR. You could find it for less on ebay or something.The model number of the bluetooth module is AUBTM-20 .Its  a Class 2 Bluetooth SPP module (Class 2 meaning that its range is around 10 meters/ 30 feet).

I added a relimate connector to make it easy to connect it a breadboard or to connect jumper wires.I had the following connections on the module taken to the connectorGND,VCC and the RX and TX connections of the serial port.

Step one : Test the module

Just power up the Bluetooth module(I Fed in power to the Bluetooth Module from the 3.3v output of my arduino ) and scan the bluetooth devices on your PC/laptop.If everything’s done correctly you will be able to find a bluetooth device named AUBTM-20 or something simliar.You will be asked for a pairing code in case of the above model (AUBTM-20)it is 8888 but it might be different if you are using a bluetooth module from another vendor.On my WINDOWS 7 Laptop it showed up as “AUBTM-20” under devices and printers.

Right Click on the device name in the devices and printers folder under the hardware tab .You will find a Standard Serial over Bluetooth Link and the COM port number writeen in brackets. Note down the COM port number.This completes the Basic test.

Step Two: Verify The COM link.

you will need to verify if you are able to send and receive data over the serial port to be able to use the device in your project for that. I used the FT232RL USB to serial converter chip on-board the arduino. But remember to remove the ATmega processor chip from the socket.(You’re out of luck if you have one of those SMD versions of the arduino 😦 .In this case you will need to get hold of a 3.3V power source such as the lm1117-3.3 and a FT232RL breakout board from here or here ) before you connect the bluetooth module to the arduino. Now Connect the RX line of the Bluetooth module to the TX line of the FT232RL module or you arduino DIgital Pin 1 and the TX line to the RX line of the  module or to that of the arduino.

Now open a terminal application such as TeraTerm (You can download it from here) select the serial port on which you connect your arduino/FT232 module(you can get the com port number of the FTDI device in the device manager under COM ports -> USB serial Port).Open a terminal with the COM port number of the The FTDI device and set the baud rate to 9600 ,8bit -data,Parity- none,1 -stop bit,Flow control -None.

Now open another COM port,this time with the for the serial COM port of your bluetooth device that you had noted down in the first step. The settings of this COM port will also be the same as above FTDI device. IF all the connections are proper and the link is established then anything you type in the FTDI COM terminal should appear on the Bluetooth COM terminal and vice-versa

The +CON:1 is something that the Bluetooth module gives out on the COM port whenever a device is connected .This Proves that the device can successfully communicate over the serial port

Step Three: Finally connecting the Bluetooth module to the Micro-controller.

Here’s a quick arduino script to verify everything’s fine .

void setup() {
  Serial.begin(9600);      // open the serial port at 9600 bps:

void loop() {
    if( byte( == 'a' )) {
        Serial.print("\nHey!");       // print Hey

Just open the arduino IDE and open the serial terminal.Set the COM port number that you noted down in the First Step and the baud rate to 9600. Just type an “a” without the quotes  in the terminal and you should get a reply with a ‘Hey!’.A word of caution the Bluetooth module works at the CMOS voltage range of 3.3V and can take only upto 3.7v max so while interfacing with TTL level devices such as the ATmega8/168/328 of the arduino level conversion will be required (check out this app note from NXP).I chose to use the 3.3v Level Atmega8L instead since the device can work at 3.3V no level conversion would be required.This is the final device that i made uses the LM1117-3.3 as the power regulator to regulate the 12v from the wall wart.

For microcontrollers such as LPC1768 and LPC2148 which run at 3.3v levels no level conversion or modification would be required at all.All that would be needed to be done is to connect the rx,tx and the ground lines of the Microcontroller to the Bluetooth module and you would have  a Bluetooth enabled microcontroller project!

The board was first designed with the Atmega8 then i added the 3.3v regulator and switched over to the Atmega8L.The Mosfets and other devices onboard are for another project that i’m currently working on.Will Post about the project in my next post.Post in the Comments below what you think about it !

123 responses to “Adding Bluetooth To your Microcontroller projects

  1. Hey that’s a good post! U said that those things work at 3.3V right? So I have an arduino uno which has a 3.3V pin. So can I directly hook that pin to the PWR pin on bt module? And the TX And RX directly frm the arduino to the module or do I need any thibg xtra?
    Thanks and pls reply fast coz I’m gonna buy that module!

  2. thanks! so i should make a level shifter right? so one question the arduino u build(in the pic) wat voltage does it run on?3.3V or 5V the atmega needs 5V right so the did u use a level shifter? and the module is it flimsy? or sturdy(i meant if it will snap and break fast or it wont)and could u send me real time pic of the module(i want see if i can hand solder it) i just 14 so im not good this!!
    anyway gr8 post….!!!!!

    • Yeah that seems to work.
      Anyways here’s another schematic for a level converter.
      And the Board that i made in the image is a prototype made on a protoboard.It is fairly rugged and is a good way to make prototypes.Yes you can make such a board for yourself and it is fairly easy to solder.
      In the board that i made the processor itself is powered from a 3.3v Supply so the Rx and tx lines are operating at 3.3V so the bluetooth module and the Processor can communicate without any level translation.

  3. Please tell me the name/address of the shop on Lamington Road where the bluetooth module is available. Thanks !

      • Sorry for replying late … thanks for the info.

        I’m connecting a Data logger to a PC. Presently this is done via serial to USB bridge, but Bluetooth seems a better option.

        But now I have a problem…. how to pair automatically to the PC ?
        I have to every time remove the device & re-install for pairing to occur.
        Any solution for this,? Thanks !

        Can we communicate by email ? somehow I did get notification of your reply, even though I had subscribed.

        My email:

        I work in Goregaon. Thanks !

  4. Dear Murlidhar,

    Thank you so much for a great illustrated blog post.
    I am looking for this setup since long time.

    I have some questions –

    1. What is the difference in between AUBTM20 and HC-05 Bluetooth modules?
    link of HC-95 –

    2. Please provide link for developing Mobile application help.

    3. Please provide some more details on pairing process.

    Thanks again

    • Thanks a Lot.

      I guess the HC-05 module is similiar to the AU-BTM20.Both are Bluetooth serial port modules and are based on the same Bluetooth chip from CSR.But i would suggest you verify for yourself before getting the module.Heres a data sheet for the HC-05 .But the pairing code and the Pin Connections will be different for the HC-05.

      For Mobile Phone application development i would suggest you check out This guy has a good tutorial on development of mobile aaplication for nokia s60 based phones.For Android and other mobile phones there are other resources such as Xda-developers, etc.

      What Part of the pairing process are you having trouble with and what OS are you using?

      • Dear Murlidhar,

        Thank you so much for detailed and quick reply.

        Thanks for mobile app development link. Sorry i forgot to mention that i am looking for java based tutorial because i dont have Symbian mobile.
        Please give a link for java app also.

        I have just ordered AUBTM20 so as soon i get it i will ask for pairing help also.

  5. i ws looking for such tutorial since long ago. U hv provided a nice satisfactory explaination. Thank u so much for that.
    I jst want to ask u is it necessary to perform the 2nd step coz i dnt hav the FT232RL module. Also pls send me any link for development of app for nokia 5230 using qt or c++. Thanx in advance

    • The second Step verifies that the serial Bluetooth Link has been established between the two devices.

      For this you can use A max3232 chip Instead of the FT232RL cable. the chip is available for cheap around 20-30 rs. and build a simple circuit using the chip. You can refer to the Max3232 datasheet fro more info on the circuit. But you Should have a spare serial port in your PC for using the Max3232 serial cable.

      For Building apps Using Qt i suggest you refer to the nokia Developer wiki here

      Let me Know if you need any more help!

  6. hey thnx for ur quick rply and sry for replying u late.
    in the second step of verification, if i m right, u have used that FT232RL only for serial to usb conversion. If i m right can i use the USB_D+ & USB_D- pin on the aubtm20 itself for usb connection. If this is posible how to do this.
    in the data sheet of aubtm20 they have mentioned that these usb pins can readily be conected to any usb port. Bup how to this this.

  7. hey i m waiting for ur reply…
    I have completed the second step. My laptop doesnt have a rs232 port. So i used the usb to rs232 cable. And then made a circuit using max3232 and connected it to pc using d cable.
    The connection was succesful. I opened the two ports as u explained. +con1 was displayed also i was able to see the letter which i typed i one window into another.
    But the problem is once the connection was established about 15 to 20 seconds letter i could not communicate between the two ports. Also the aubtm20 becomes undiscoverable.
    What should i do. Is this the prblm in bluetooth module or anything else.
    Pls rply… I m waiting.

    • Hey Aniket,

      I havent Tried connecting the USB to the bluetooth module directly. and i would not suggest that since the USB protocol is a bit complex and would not be supported by the Atmega8.

      If you want a simple C code for UART interface for the Atmega8 you can get it from here .The link is for a Excellent UART library developed by Peter Fleury. Just follow the instructions in the manual included with the code to get started with the UART interface for the atmega 8!

      Also if you are experiencing disconnecctions of the bluetooth module after a few minutes try putting the bluetooth module in bluetooth slave mode by connecting the pin 25 (PIO5 In the aubtm-20 datasheet) to the ground. And make sure nothing is conencted to th pin 4 (PIO3). Best of luck 🙂

  8. and i dont have an ordiuno. For programing atmega8 i use avr studio 4. I tried a lot bt could not write d program for serial communication in atmega8. Pls provide me c code for the serial communication for avr staudio 4.

  9. thank you murli sir for such a valueable informations and your help..
    sir can you please tell me that can i use HC-06 in place of AUBTM22 ?i can’t recall the exact link of that bluetooth but i do remeber that i have seen it in robokits’ website. i was wondering that should i buy it as an replacement of aubtm 22 or not.
    please reply me soon sir..
    thanks in advance “_”

  10. Hi
    Thanks for the really informative post.I am doing a miniproject which involves interfcing a bluetooth with a microcontroller and sending stuff to another mcrcontroller based bluetooth. We have our serial communication program ready, but we were wondering if we require any special bluetooth protocol for the same?

    • No You dont need any Special Protocol to communicate over bluetooth. But the voltage levels of the signals from the microcontroller should be in the 3.3V range . Since the Most bluetooth modules work on a accept signals in the range of 0-3.3v. You might need to use a level shifter to do that.Let Me Know if you need any more help on the project!

  11. Hi Murali. It seems you’re very good at bluetooth.
    I actually am interfacing a bluetooth module with 8051 microcontroller. And I need to have an android app that runs the Aubtm 20 module which activates the 8051 and runs the motor.
    I can’t seem to develop the app on my eclipse Android SDK plat form and I am fully stuck, I would need help. What should I do?

  12. I need to have an app that communicates with the module, and I don’t know much about android app program, so could you please help me?
    Thank you! 🙂

  13. Hey thanks! but actually its not making an app i have a problem with, its making an app with bluetooth requirement. and the android tutorial wasn;t very useful. so what shoud i do

  14. Hey Murali,
    I am building a bluetooth enabled bot. I use an AT89C52 along with AUBTM-20. You haven’t mentioned here about the AT commands that we need to use.
    I paired the module to my laptop using AT commands and I could get whatever I send via a serial port to the bluetooth’s configured serial port.

    I am stuck when I interface the aubtm-20 to the microcontroller directly. I just wanted to know if the procedure to interface the module to the uC is the same as that was done using AT commands?
    I am doing the following:

    1. Wait for an OK from the bluetooth module (I get this)
    2. Send LLL (I did this)
    3. Wait for an OK from bluetooth (No reponse here!)

    Could you tell me where I am wrong?

      • Hello Kunal, I am assuming that you are trying to communicate to AUBTM 20 from the PC/laptop. You need to have a terminal program – like hyperterminal or terminal.exe. I used the aubtm module with built in max 232 circuitry, so it was easy to plug it into the computer’s serial port/usb port. After plugging the module to serial/usb port, you can configure the baud rate,com port etc in terminal.exe,. Then you start sending AT commands!.

    • hey Ali,

      Please refer to this project i made,Here i control the LED color over bluetooth via PC and Mobile. i have included the source. code and the PCB layout files for the same.Feel free to check it out and let me know how it goes.

  15. hi im working on quadrocopter project which requires a bt module at the reciever end and another at the transmitter so iwas wondering how to pair two aubtm 20 together without any extra things like computer? do u know how to?i need them to be paired as soon as it is powered!!

  16. murali could u pls reply to my question?
    im working on quadrocopter project which requires a bt module at the reciever end and another at the transmitter so iwas wondering how to pair two aubtm 20 together without any extra things like computer? do u know how to?i need them to be paired as soon as it is powered!!

    • hey Francis,

      Seems Like a very interesting project!

      Sorry for the late reply. I was out of town and did not have internet access so couldn’t reply.

      I Will have to Check out for my self,The pairing of two AUBTM-20 modules. Will be trying it out tomorrow,Will let you know about my progress on the project.

  17. murlidharshenoy
    i tried to use the at commands but none of em are working all im getting is an error after getting into the setup
    pls help

    • You Might need to Put one of the Modules into the slave mode. to do this Simply pull thr PIO5(pin 25 on the AU-BTM20) line low while powering up the module. And put the other module into Master mode. To do this Pull the PIO5 to high while powering up the module. after that both the devices should be able to Connect with each other.

      • wait so how does the aubtm(master)know it has to connect to the specific slave?could u pls xplain what should i do and how should i do?

      • There is an inquiry (AT+INQ ) at command for aubtm-20 module. On the master side you just have to run this command. It will fetch a list of available discoverable bluetooth DEVICES. Select the slave module. Connect to the slave device in the list using the connect at command (AT+CON).
        You can get the detailed description in the at command set reference sheet for the au-btm 20.

        Do let me know how it goes!

      • Hello Muruli Sir,

        I am trying to interface AUBTM-20 with LPC2148.
        When i connect bluetooth module with laptop, first OK response is recived, When i enter LLL i am getting response as OK. but next what ever the AT commands i enter its commiung as error. Can you please suggest me to resolve this issue….

      • Hey Asha,

        I think it might be due to a missing carriage return and line feed character.

        The AT command Set of the AU-BTM 20 requires the command issued from the host to be in the format as shown below

        You may use the terminal program such as Tera term, which gives you options to send a cr and lf character after each transmit

        Refer to the Command Set for more info

  18. hi sir awesome description…i am trying to control appliances using relays thru arduino via bluetooth interface….everything is fine but i am struck at AT commands…how to configure the aubtm to slave…master and automatic mode and what is spp mode…plzz explain i am unable to get it…can we configure these modes by at-commands and also by pulling some pins low?… unable to handle at commands so plz tell me which pins are needed to be pulled low such that if i am sending character “a” or anythng thru my fon it shud be printed on my arduino serial monitor….thanks in advance….

  19. else sir plz give me the set of commands in the same order as to configure it in slave mode or spp….such that if im sending characters it shud recieve….and when we purchase this aubtm by default what is the mode it has?…when i connected it i got ok and then i entered lll then i got ok then after that im gettng all errors plz help regaring this mode configuration ….my requirement is that it shud recieve the characters sent by the fon thru android app and give those characters to arduino to decide upon…

  20. sir could u tell me the pins which i need to configure on that aubtm-20 such that it can just recieve charaters im sending once it gets paired?

  21. hi murlidharshenoy,
    i need ur help for bluetooth project, at start, i establish connection between bluetooth module connected to arduino & other bluetooth compatible device my application finished, next time i want to use that application, this bluetooth module start automatically or need to send AT command again

  22. hi Murali,
    I am not able to type anything on tera term vt screen for step 2. the screen is just blank . Please help plz


    • Hey Shalit,
      Open teraterm Under setup menu ,check the Local echo box. and you should be able to see what you are typing on your keyboard on the terminal……provided you have connected and opened the comport on which you have connected your bluetooth module! 🙂

      • thanks now i am able to see what i am typing but still whatever i am typing on the bt com port is now getting displayed on the arduino com port please help.

  23. Hi Murali,
    How set profile in AUBTM-20 MODULE i have worked all basic command but cant use bprofile(AT+BPROFILE =?) and kindly guide me to check the module and tell me wat is the procedure to send and receive the data from aubtm-20 to samsung moblie??????? pls urgent help me???????

  24. thanks for helping me:):):) I was able to do it with sony X8 moblie:):):):) Thanks a lot:):):):):):)
    Now i am planning to interface PIC micro controller with AUBTM-20 module????? wat are the steps i need to follow??????

  25. i am trying to connect aubtm 20 to NOKIA handset.. AT+CON is working properly and the connection is established. However, after the connection has been established whatever key i press on the keyboard causes the spp connection to b disconnected.. plz help me

      • Hey Shraddha,

        I dont think making and disconnecting phone calls is supported over the bluetooth serial port profile(SPP) . For that some other profile such as HSP or HFP could be used. I am not sure whether those profiles are supported by the AUBTM-20 module.

        Also Make sure your device is properly paired and the two bluetooth devices are not separated by a distance of more than 10 meters to allow for a stable and reliable bluetooth connection.

        Let me know if you need any more help !

  26. handsfree profile is built over spp..according to the documents it is mentioned that in order to control calls thru handsfree profile..first we need to estabblish an spp connection and then give AT commands over spp conection to the cell phone..plz reply to my upper post as well..coz m really stuck there..

  27. let me explain u in trying to establish an spp connection with a cellphone and try to control the calls using atmega128. the profile needed to do this is the handsfree profile which is built over implementing tat profile on atmega128 thru programming.

  28. Hi

    I’m new to this stuff.Can you help.

    I can’t locate to buy this AUBTM-20 module in the USA. Do you
    know of a compatiable bluetooth module that i could use and will work.

    I’m making a DTMF receiver and need to connect a bluetooth module
    to the HT9170 output.How can i do this. Do i need a microcontroller
    and if so which one. you can reach me at the e-mail i provided.

    • Hey PJ,

      I would suggest you get a microcontroller board such as an arduino.

      The bluetooth module similiar to AUBTM-20 can be gotten for cheap from ebay or

      you will need the microcontroller to interface the HT9170 dtmf chip with the bluetooth module.

      Check out or arduino or adafruit forums. you will find lots of helpful and interesting stuff there!

      Do let me know how it goes! Let me know if you need any help!

  29. sir,i’m doing my mini-project as a wireless mouse,but i’m not getting ‘how to read commands at laptop side sent by bluetooth module using micro-controller on another side…so can u help me out???

  30. hello sir,
    i am working on a project using hc05 and arduino. i want to configure the HC05 chip to change the password and pair it automatically. i am unable to do it through at commands.Infact the AT commands give no response when typed in hyperterminal or programmed through arduino. I have tried pullin the pin 11 high as mentioned in several websites but in all efforts in vain. there is no response. can u help me configur the chip asap? pls help me out

    • Hey twins,

      Make sure you send line feed (\n)and carriage return(\r) characters at the end of the commands(refer the command set for hc-05). you can also automate this by conifguring your terminal software.
      which terminal softwre do you use?
      Try using terminal software such as hecules or teraterm.

      let me know how it goes!
      Best of luck!

  31. Hello Sir,
    I was struggling to connect LPC3250 with Android mobile via bluetooth, I found this blog more useful. Can I use the same module and procedure for it connecting with LPC3250 instead of Arduino.
    Thank you

    • Glad that u found my blog useful Mashal!

      Yes you can use the same method to connect any microcontroller to the bluetooth module. But make sure you to get the pinouts right before making the connection.

      Best of luck!

      • Thank u Sir,

        I bought an AUBTM 20 and connected with my LPC3250. The first step is ok, the device got detected and my com port number is 9. But in second step when i gave the com port number in hyperterminal, and i got the message “unable to connect to com port9. Some other application is using it” could u suggest me some solution.

  32. Thank u for your guidance sir, My device is working fine. Whoever want to transmit and receive data between your AUBTM 20 and android mobile can use the android application Blue term instead of SENA Bterm. Its working fine.

  33. HI this is suresh from khargar i have a aubtm v1.3 and i use docklight as a terminal on pc which is connected to module through rs232to usb convertor
    now when i type LLL ok returns everything works fine at+inq also but i try to connect to my cell whose adres i feed in AT+CON with profile 2 then it ask cell for passcode then it shows +CON=0 whats wrong? at+mode=1,bprofile also i have set to 2
    plz help project concerns with communication of android with autbm

  34. Hi,
    I am working on with the same AUBTM-20 module. For the first step mention I connected it as required (i.e. only giving it the Vcc(3.3V) and Gnd). But it is not detectable on ,y PC. What can be the problem?? Any suggestions!!

  35. I am Using my HC-05 Bluetooth module and I connected it in my Arduino uno r3,my wires are all fine.When I use my mobile phone to communicate with BT module I’ve got some problems: My phone can pair with BT module but there were no connections,my phone says “paired but not connected”,do you know what to do?

  36. Thanks for the tutorial above will be useful to enhance my studies .

    But I am seeking information for my school project and this hard to find what I want.

    I need help to develop the program and find out which Bluetooth module is suitable for this use , with a range of one meter.

    If you can just tell me about the program is already great. However, this program can be applied in any Bluetooth ?

    Example of what I need : I will connect my smartphone to a Bluetooth device that has an alarm connected to an accelerometer , and if someone touch it , it turns on and emits an alarm sound right there on the product, and also sends a vibration to mobile with Android , and when I distance myself from alrme , say 1 meter. the system is triggered , and when I approach, the alarm system turns off .

    Let’s put it this way , my Android Mobile is the receiver of the other Bluetooth notices containing the alarm , Bluetooth with alarm that this is the transmitter , it transmits the alarm on my cell phone and also emits a loud alarm sound the circuit itself . If anyone touch it he sounds the alarm . Would like Keyiess Passive Entry – PKE ) call that drive chip .

    Many thanks and a hug

    • Hey! Glad to hear that you found it useful. if you are looking for a cheap bluetooth module i would recommend searching for “hc-05” on ebay. It is a very simple module and very easy to interface for beginnner. Your project sounds very interesting. you can also look through my other projects for more info on using the bluetooth module. do let me know how it goes and feel free to contact me for any help! Please do share the pictures of the project when you are done! good luck! cheers!

    • you can buy the modules from the Visha electronics shop in Lamington road, Mumbai

      Here’s the full address
      349, Lamington Rd, Shapur Baug, Girgaon, Mumbai, Maharashtra 400007, India
      +91 22 2386 2622

      Hope that helps!
      Do let me know of your updates on the project!

  37. hi,i am working on the project for controlling the motor via bluetooth and smart phone. after purchasing hc-05,is it necessary to program it via AT commands or i can directly connect it with 8051 microcontroller??
    and can you provide me the embeded c program for these type of projects??
    please help….

  38. Thank u sir,
    but one more question is,
    if i directly connect the bluetooth module with 8051 then i need to write a program to send the characters to the 8051 from module via android?? or i only need to write a program to run the motor?? please help.

    • Hello, my hope is that you help me.

      The problem is: How do development board Bluetooth (CSR1010) be recognized by my PC?

      I bought a development board CSR1010-DK-10169-1A….0…1c.1.39.serp..1.6.1114.ZHKtMdJLG_8

      I’m trying to make it be recognized by the PC, and can not, the forum sought help them and received the following help:
      You have to remove the Windows driver and select CSR driver to be able to control dev PCB via USB.

      check if your RS232 to TTL is suitable, you can:
      1. Verify that the voltage is 3.3V

      2. Pinos short TXD to RXD. pc Canvas Set the terminal set to 9600, no local echo, select the right COM port and type some characters. if you see the characters appear on the terminal screen, the OK cable and can be connected to the PCB.

      Please note that I am not employed CSR and this is just from my personal experience.
      The CSR1010-DK-10169-1A contains a single board which has a USB-SPI converter onboard.

      It does not include features USB-UART, so if you want to connect to a COM port on a PC, you need to provide this via a USB-UART cable outer, ie a cable that would include the FTDI chip internally. The board does not include push button or LEDs, as part of CSR1010 project. The kit does not include the dual-mode dongle or battery. Both kits will allow you to begin development immediately, without having to buy anything else.

      What I did not?

      You have to remove the Windows driver and select CSR
      How to do this? remove the drive?

      So I bought a TTL cable, how to connect it?
      PuTTY installed but how to select the USB port

      And the TTL cable I have is this:
      HE said: check if your RS232 to TTL is adequate

      Usb Converter Rs232 To Ttl Pl2303hx
      Product Features:

      USB Interface USB Serial (RS232, UART) converter TTL level. Used as the main CI PL2303HX.

      Have power outputs 5v and 3.3v, ease of use and low power circuits.

      Ideal for projects that require serial communication with a computer or recording / scheduling of compatible devices.

      For projects requiring the use of the level (usually the famous MAX232) converter because its output is already in TTL level.

      Thank you very much.
      a hug

      Eduardo castellani

  39. hi murlidharshenoy,
    i need ur help for bluetooth project, at start, i establish connection between bluetooth module connected to pic microcontroller 16f877a.I am stuck when I interface the HC-05 to the microcontroller directly. I just wanted to know if the procedure to interface the module to the uC is the same as that was done using AT commands?
    I am doing the following:
    1. Wait for an OK from the bluetooth module (I get this)
    2. Send A (I did this)
    3. Wait for an OK from bluetooth (No reponse here!)
    Could you tell me where I am wrong?
    Give me any UART source code for testing.


  40. heloo i am working with lpc1768 board i want to interface bluetooth module HC-05 through UART .can you send how to connect the pins.

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