Timed Robot/Circuit - Need a circuit to turn LED on and off at specific intervals

Discussion in 'The Projects Forum' started by zaidpirwani, Jun 20, 2009.

  1. zaidpirwani

    Thread Starter New Member

    Jun 20, 2009
    3
    0
    Hi, I hope this question is in the right forum.

    I am new to practical electronics, I am saying this as I have good theoretical knowledge but no practical experience.

    I have to make a robot, I have assembled it. the goal is to run it in a desired path and switch on LEDs at specific places.

    I am not using any kind of sensors and just want to turn the right motors at the right times.

    For the sake of simplicity, I am testing with LEDs right now and if my circuit works then I will just change the LEDs with relays connected to motors, I can use both normal relays and latching relays (which only need a pulse to turn on or off).

    Suppose I have 4 LEDs (L1, L2, L3 and L4) and they have to turn on and off like this.


    1. Everything should remain off at first for about 10 seconds.
    2. L1 should turn on for 10 seconds then turn off.
    3. L2 should turn on for 5 seconds then turn off.
    4. L1 should turn on for 25 second and then turn off.
    5. L3 should turn on for 5 seconds then turn off.
    6. L4 should turn on for 5 seconds and then turn off.
    7. L1 should turn on for 20 seconds then turn off.
    8. L4 should turn on for 5 seconds and then turn off.
    9. L3 should turn on for 5 seconds then turn off.
    10. L1 should turn on for 25 second and then turn off.
    11. L3 should turn on for 5 seconds then turn off.
    12. L4 should turn on for 5 seconds and then turn off.
    13. THE END.

    That's about it. I have tried using 555 Timers, in Monostable mode, but the problem is that 555 timers just turn on after trigger is pressed and then turn off after a while. But I need to turn on and then off at specific times.

    I think a PIC, or BASIC STAMP II, or any other Microcontroller would work, someone also told me to use ATMEL 8051 but I do not know which one to use and more importantly how to use. I know a little bit Assembly Language and have sound knowledge of C language and BASIC.

    Any help in this matter will be highly appreciated, as I have very less time to turn in the project I will be posting this same question on other forums also. Please guys help me as I have no idea where to start, I have been searching on the Internet for a week now and have not gotten anything. The goal is to get timing done. i don't care if there are 12 different timers for the job or if one microcontroller. Please people help me with this. or please guide me.

    In my opinion, WHICH CAN BE WRONG, I just need to have a microcontroller, which would track time, we will have to write a program for that, (I think loops will do the trick OR is there anything else I can use, as I cannot get much information about timing through microcontrollers on the Internet) with 1 second accuracy and send pulses at specific times to specific pins to turn the relay on and off (as I had said earlier, I can use latching relays). No Input is required, only four output pins need to work so that for every one of the 12 functions defined above two pulses will be sent, one for on and one for off.

    Again guys, I am very desperate and need help in this. Any help in this matter will be highly appreciated and I will be very grateful to you all. ;);):):)
     
    Last edited: Jun 20, 2009
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    As you learn to program the microcontroller that runs your robot, I suspect you will find that the task to turning on LED's at specific places and ro specific times will be quite trivial. I would be much more concerned by selecting the microcontroller and making the interfaces that let the robot move and sense the walls of the maze.

    One way of keeping time is to have an accurate oscillator present. Just let that input accumulate a count. The value of the count gives the elaped time. The faster the oscillator, the more accurate the determination of interval.
     
    Last edited: Jun 20, 2009
    zaidpirwani likes this.
  3. zaidpirwani

    Thread Starter New Member

    Jun 20, 2009
    3
    0
    Thank you very much, I have started work on your advice, but if you know any good book or site where I can see some samples, then please post them here.

    Thanks again for your timely response.
     
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