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  1. bob weir

    Digital programmable CDI ignition for 2-stroke engines

    this post is to show how the -10 deg flywheel signal gets converted into a pulse the CDI circuit can use. note that the uC does not use the -10 deg signal. one image is of the flywheel signal and the 2-transistor circuit that changes the -10 deg half-sin wave to a 0-1-0 pulse. at the time...
  2. bob weir

    Digital programmable CDI ignition for 2-stroke engines

    if you Google " programmable digital ignition cdi" you will find what others have been up to . some of what was found relates well to what is being presented here. and is offered for reference support and comparison. three items today are images. the first is another flywheel showing...
  3. bob weir

    Digital programmable CDI ignition for 2-stroke engines

    today's post will re-visit a foto from last sept. it shows the flywheel on the yamaha 225 with the magnet visible on its top surface. not shown but next to the flywheel is a 2-wire coil sensor that detects the magnet's field when it comes rotating by. the magnet strip is about 2" in length...
  4. bob weir

    Digital programmable CDI ignition for 2-stroke engines

    this post is to show what the scope sees the voltage on C2 doing when U1 recieves a 200us pulse to drive the Q1 FET 'on'. there are 2 screen images. qp8 is with a horiz .002 sec per div. and qp11 is 200us/div qp8 shows how C2 takes about .010 sec to recharge. the probe for C2 is on the...
  5. bob weir

    Digital programmable CDI ignition for 2-stroke engines

    here is the 2012 version of the CDI circuit being used for this project. i cant find any way to post it here opened up. so i guess you'll have to open the file on your PC and / or print it out.
  6. bob weir

    Digital programmable CDI ignition for 2-stroke engines

  7. bob weir

    Digital programmable CDI ignition for 2-stroke engines

    this image is what the 1054z rigol scope captured. one of its 4 probes was connected to the feedback resistors for one charge cycle. the cycle is done when the C2 cap reaches 250 V. then this feedback 2.5 volt signal reaches the LF353 comparator '-' input and matches the '+' input so then the...
  8. bob weir

    Digital programmable CDI ignition for 2-stroke engines

  9. bob weir

    Digital programmable CDI ignition for 2-stroke engines

    an e-mail alert today told me of a new message. from new member Dabidoh. welcome to this forum. the thread may appear to be dead. but the work is going on . by coincidence today is when i will spin up the Yamaha 225 this CDI project is meant for. the purpose is to verify that the...
  10. bob weir

    programmable cdi, looking for a good project or kit

    Bluejets - thanks for the reply msg and link. and , you are right, on giving it a look it is of some interest. and further on down the road it is expected that their coding methods will be adopted. for now tho i'm reminded of being in the 2'd grade with learning coding and understanding how a...
  11. bob weir

    Digital programmable CDI ignition for 2-stroke engines

    hi dr X , its good you have a plan. and the attitude that it wont be such a big project. i hope this is how it turns out for you. and that you are not mistaken with your estimate of the future. your comments and requests have all combined to push me into doing some fresh thinking...
  12. bob weir

    Digital programmable CDI ignition for 2-stroke engines

    dr X , hi. gads , you've got a load of bikes to work on. this is going to be one major project for you. your interest and enthusiasm is most welcome. i was half afraid you'd want to do the code in C. god forbid. then we'd never be able to move along and understand each other...
  13. bob weir

    Digital programmable CDI ignition for 2-stroke engines

    dr eXntrik - hi. what you are trying to do is a project i have been with for my motorcycle for the past year. its a 225 yamaha and the analog ignition circuit died. and is being updated with a digital one. the hard part is coming up with a coded micro-controller to handle the...
  14. bob weir

    Digital programmable CDI ignition for 2-stroke engines

    hello you guys. i just found this site on doing a google search for a 'homemade cdi ignition system.' and by the existing title is read '2-stroke' . right now i'm writing an assembly code program for a yamaha xt225 4-stroke. in MPASM v. 8.92 . its about 2/3 done. its been a project...
  15. bob weir

    programmable cdi, looking for a good project or kit

    David hi. we both share a desire to update a 4 stroke engine with a modern digital cdi ignition. how is your search going ? the critical thing that my 225cc 4-stroke engine has for its old analog circuit is a coil that picks up and makes a 1/2-sine-wave when a magnet on the flywheel...
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