RC servo receiver & transmitters?

Discussion in 'Homework Help' started by ayashifx55, Dec 17, 2010.

  1. ayashifx55

    Thread Starter New Member

    Dec 17, 2010
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    Hi everyone,

    I would need some help. I am trying to plan a project on electronics. Everything has to be from scratch though we are allowed IC's but no microcontrollers like TX2B , pre-receivers , pre transmitter, ect ...

    I will be making a radio controlled tower which can mount a camera and when i press a button, the servo will turn and hit the mounted camera's button and take the picture.

    X axis (2 buttons) , Y axis (2 buttons) and trigger (1 button). So i'm guessing 5 channels , i will use 3 servos.
    Anyone knows any transmitter & receiver schematics?

    I'm planning on using 555 timer ic chips and connect them with receivers because they seem to be the most simple.
    Transmitter still not sure, maybe simple collpitt oscillator but the problem im having is i never done more than 1 channel. Teacher obviously never taught.
    All we learnt the most useful is making a microphone FM transmitter

    This is the servo which i will be using , 3 of them. There is no precision required. All i need is for it to work wirelessly (FM frequency)
    [​IMG]

    This is my block diagram , may be changed if needed

    [​IMG]

    Thank you very much for your help.
     
    Last edited: Dec 17, 2010
  2. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    That assignment borders on the bizarre. What can you use? Can you use comparators, op-amps, logic gates, microcontrollers? Can you use a servo, or do you need to make it from BJT's?

    BTW, the 555 is a pre-built chip. Are you planning to make one from the available schematics?

    John
     
  3. hgmjr

    Moderator

    Jan 28, 2005
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    Is this a class project? If so, then it belongs in the homework section of the AAC forum. I will move it for you once I have your reply.

    hgmjr
     
  4. ayashifx55

    Thread Starter New Member

    Dec 17, 2010
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    Jpanhalt, thank you for your reply.
    We are allowed to use simply IC chips like 555 timer, comparators , op-amps, logic gates but we are not allowed micro controllers because it requires programming from what i know and it is a "pre-build" circuit. For example, TX2B is not allowed.

    Sorry, i did not know there was a class project section hgmjr.
     
  5. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    Where are you? How far do you have to have the transmitter and receiver apart? Have you considered using IR? If you must use RF, what frequencies? How much selectivity do you need? That is, can you use superregen for your receiver? I might find some old schematics from the 1950's that used vacuum tubes. Will they help?

    John
     
  6. ayashifx55

    Thread Starter New Member

    Dec 17, 2010
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    I'm hoping to use FM frequencies 87-107Mhz. At school, the spectrum analyzers are only up to 500Mhz
    Teachers hope we get at least 1 meter. I'm aiming for 10meters only, so theres no fancy range & signal clarity here haha. We are allowed to use crystals so i dont absolutely have to design my own tank circuit.

    I am a dawson college student in Canada, Montreal.
    By superregen, do you mean super heterodyne ?
     
  7. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    Can you use IR. Then you have generation and detection of the carrier licked very simply, even if you don't use one of the TSOP-type of detectors.

    Do you also have to build the servo(s)?

    How many channels do you need?

    John
     
  8. Len Whistler

    Member

    Dec 10, 2010
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    Activating the camera shutter like that is odd. I would use the cameras electronic remote or hack the cameras button and replace it with wires.
     
  9. ayashifx55

    Thread Starter New Member

    Dec 17, 2010
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    dont worry, were allowed to buy servos !
    I have not much knowledge on IR(infrared?). Most we learned was the photodiodes with the dark current and light current

    Horizontal - Right Left
    Vertial - Up down
    Trigger (maybe ill disassemble the camera and simply make a switch , when it received signal it will close switch to shutter)

    So 5 channels ? I have attached my proposal to the teachers. Please take a look.
     
    Last edited: Dec 17, 2010
  10. hgmjr

    Moderator

    Jan 28, 2005
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    No problem.

    It is just that homework/classwork threads come with certain expectations of some effort on the part of the member that initiated the thread. In your case you have made an effort to get your project up and running only to encounter a devil of a setback in the likely destruction of your servo.

    There is a valuable lesson to be learned in your case. The more precious the component are the more precautions are needed.

    hgmjr
     
  11. Len Whistler

    Member

    Dec 10, 2010
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    Instead of a doc document I would export it as a pdf. I'm on Linux and can't open the doc, while a pdf document can be opened by windows, linux and mac computers.
     
  12. ayashifx55

    Thread Starter New Member

    Dec 17, 2010
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    I have uploaded a block diagram if that may help.
    PDF uploaded !
     
  13. ayashifx55

    Thread Starter New Member

    Dec 17, 2010
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    what happened to the people i chatted with ? :confused:
     
  14. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    The example in the PDF shows a Futaba R/C Aircraft controller, a Futaba receiver is decoding and running the servos. This is a "plug and play" system, except for the physical mounting of the devices.

    I don't see the requirements that you need to build all modules from scratch and without uCs. A uC is almost required to multiplex all the channels into the datastream, and another to decode them and parse to the correct servos.

    Trying to build an RF Tx and Rx with a single channel from scratch is a feat in itself for somebody new to electronics.

    Can you verify what components can be and what cannot be used? The original question and what is shown in the PDF do not match. :confused:
     
  15. ayashifx55

    Thread Starter New Member

    Dec 17, 2010
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    Ok,

    This what my departement chariman said :
    "In general if you select an IC that does everything then the answer will be no. We need to be able to evaluate your technical ability.:

    He suggests that i transmit 5 different codes and that the receiver decodes the 5 different codes and do the actions.
     
  16. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    What have you been taught so far?

    RF Design?
    Microcontroller programming?
    Modulation techniques?

    This would be a rather huge project to do all of the above from scratch.

    Without a clue as to what area of "technical ability" they are looking at (RF, Digital, control systems, etc), it is a bit hard to give advice.
     
  17. Len Whistler

    Member

    Dec 10, 2010
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  18. ayashifx55

    Thread Starter New Member

    Dec 17, 2010
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    i was thinking using 8-psk modulation, having each phase represent each action.

    000 - Move left
    001 - Move Right
    010 - Move Up
    011 - Move Down
    100 - Trigger

    We got some theories on modulations, how they work but never taught how to build one lol.

    In telecommunication, we were never taught any programming , especially not micro programming .... All i leanred is Qbasic & assembly language. Can anyone show me some schematics about 8psk transmitter and receiver? I checked them out and they arent that simple, They have few block diagrams for each tx or rx

    Thanks for your time.
     
  19. ayashifx55

    Thread Starter New Member

    Dec 17, 2010
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    this is actually a final project and not a homework. Wrong section maybe? No help =( merry christmas
     
  20. bertus

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