Object avoiding robot without microcontroler

Discussion in 'The Projects Forum' started by abdullah8391, Oct 31, 2015.

  1. abdullah8391

    Thread Starter Member

    Sep 6, 2015
    53
    1
    hello again!
    I am trying to make an object avoiding robot without micro controller. below is the link from where i am taking help.
    http://www.engineersgarage.com/contribution/obstacle-avoiding-robot-without-microcontroller?page=1

    I am right now designing 555 timer control (part of object). From circuit, 555 timer is being used in astable mode.
    But how exactly is it working?
    because in astable, it will give continuous output.

    In my opinion 555 timer should be used in mono-stable.
    is my opinion correct, if not then why?
    image from site of 555 timer is also attached. (pin 2 is connected with pin 6, written on site).
     
  2. blocco a spirale

    AAC Fanatic!

    Jun 18, 2008
    1,440
    368
    The 555 is configured correctly as an oscillator/astable to pulse the IR LED at 38kHz. The IR receiver has a peak sensitivity at 38kHz so responds to the reflected IR from the LED.
     
    abdullah8391 likes this.
  3. GopherT

    AAC Fanatic!

    Nov 23, 2012
    6,073
    3,846
    The Stage 1 is only flashing an LED IR emitter at 38k Hz. Nothing more.

    Stage 2 (TSOP sensor) is looking for the flashing 38kHz pulse to reflect off of an object (obstacle). When a reflection is identified, the output changes.
     
  4. abdullah8391

    Thread Starter Member

    Sep 6, 2015
    53
    1
    But when i calculate frequency by formula, it gives
     
  5. Papabravo

    Expert

    Feb 24, 2006
    10,176
    1,799
    what -- exactly??
     
  6. atferrari

    AAC Fanatic!

    Jan 6, 2004
    2,652
    767
    A new master in suspense is born... :)
     
    GopherT likes this.
  7. GopherT

    AAC Fanatic!

    Nov 23, 2012
    6,073
    3,846
    Note that the drawing in Post 1 has the pins all mixed up - they are numbered correctly but not in the right position.
    Your timing resisters are 10k and a 20k pot (adjusted to about 14k of resistance). Your timing capacitor is 1nF (0.001 uF).
     
  8. abdullah8391

    Thread Starter Member

    Sep 6, 2015
    53
    1
    sorry,my connection was lost and i don't know why the msg was sent incomplete...
    it was 142k...
    can anyone verify what i calculated is correct or incorrect?
     
  9. abdullah8391

    Thread Starter Member

    Sep 6, 2015
    53
    1
    thanks...
    but where should i connect led IR emitter and tsop sensor.
    because it's last figure is a bit confusing... :-(
     
  10. GopherT

    AAC Fanatic!

    Nov 23, 2012
    6,073
    3,846
    There is no electrical connection. Stage 1 just flashes the IR LED...
    ...then IR (infrared light) reflects off of a wall or object and back to your detector.
     
  11. abdullah8391

    Thread Starter Member

    Sep 6, 2015
    53
    1
    Yes... And i am asking where is detector connected? On 555 timer with which pin?
     
  12. ericgibbs

    AAC Fanatic!

    Jan 29, 2010
    2,504
    380
  13. GopherT

    AAC Fanatic!

    Nov 23, 2012
    6,073
    3,846

    The InfraRed Light Emitting diode is a device. It is called by its short name "an emitter" sometimes.

    This projects works as follows...

    The 555 timer and the InfraRed LED are like your thumb pushing a button on a flashlight. All it can do is pulse the light on and off. There is no wires or nerves connecting your thumb to your eye.

    Now, in the same dark room, your eye is like the TSOP sensor. it can see the flash of light if the light hits something and reflects back to the eye. If the light hits nothing, then the eye cannot see the light.


    Do you understand why it is better to flash the infrared LED instead of leaving it on constantly?
     
    abdullah8391 likes this.
Loading...