Connect with us

Interfacing Bluetooth module to a MCU

Discussion in 'Microcontrollers, Programming and IoT' started by skoushik333, Jan 25, 2012.

  1. skoushik333

    skoushik333

    2
    0
    Jan 25, 2012
    Hi,
    I'm doing a project which involves a Bluetooth module, a Proximity sensor and a Microcontroller. Basically, it works like this:
    When the sensor gets triggered (by an obstacle), the device should be able to send a message to a cellphone via Bluetooth.
    I'm very new to this stuff, so I'd appreciate it if any guidance is offered. I've attached the circuit diagrams of the proximity sensor(which was fully assembled when I bought it), and the design which I did (which I'm guessing is wrong).
    I'd be glad if any of you can help me out.
     

    Attached Files:

  2. Harald Kapp

    Harald Kapp Moderator Moderator

    9,304
    1,888
    Nov 17, 2011
    I can't tell you about Bluetooth. But let me not ethis:

    1) operating the 8051 from 9 V is a bad idea, even with the series resistor. The voltage at the VCC pin of the 8051 will vary depending on the current consumption. Better add a voltage regulator. In this case asimple linear regulator 7805 or 78L05 should sufice. Check the power consupmtion of the 5 V cicuit to determine whether you need the larger 7805 or the smaller 78L05 and also whether you need a heatsink.

    2) The connection of P3.0 and P3.1 to TxD and RxD, respectively, looks o.k.

    Harald
     
  3. skoushik333

    skoushik333

    2
    0
    Jan 25, 2012
    Thanks for the input. I guess I wasn't thinking very much when I made that circuit. I do agree on the voltage regulator part, and I've done the same thing. Here's the updated circuit. I wanted to know if it's okay to connect the output to the Interrupt pin and program it to send the output when the INT is triggered.
     

    Attached Files:

  4. Harald Kapp

    Harald Kapp Moderator Moderator

    9,304
    1,888
    Nov 17, 2011
    Why use a voltage regulator from the sensor to the INT pin? I don't even know whether the regulator would generate clean pulses from the switched 9 V at its input.
    You can jusr use a resostor divider to reduce the 9 v to 6 V.

    Harald
     
  5. Sid723

    Sid723

    57
    1
    Jan 28, 2010
    It looks like the "proximity" sensor circuit you are using is a self contained circuit and has no real output to send to the CPU. The sensor triggers a buzzer when the infrared circuit sensor sees the signal from the infrared LED. To use it in your circuit, you will have to find a suitable point to take an output that is of a logic (0v to 5v) level that you can send to the CPU and trigger an interrupt.

    It looks like more work needs to be done before this can work.
     
  6. ronk4rompy

    ronk4rompy

    4
    0
    Oct 23, 2012
    can u explain mei whats ur acjt aim?
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-