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Farshid Jafari Harandi
08/13/05 22:06
Read: 1459 times

#99362 - Tachometer and engine timing tool
Hi ,

This time i'm planing to build a tachometer to measure engine's RPM and hopefully after that planning to show the delay time between sparks .the next feature which is currently i have in mind is to add a flash light triggered by the first cylinder's spark (which is useful for determining the Cylinder TDC position) to tune the engine's ignition timing. this should make a good diagnostic tool for the mechanics and also myself. (although this is not a new idea)

1- For determining the RPM i'll use the COIL primary pin frequency and divide it by cylinder number. this will connect throught an RC filter to an Optocoupler then fed to the INT0 .

2- As for the spark detection i am planing to use the Spark wires (high voltage) through a Rogowsky coil. so my final device should have 8 Rogowsky coils max. ! i don't have any experience in using Rogowsky coils , but i'm rereading the info in this forum . so my initial plan on this is to use a 'Transistor + OptoCoupler' after the Rogowsky output and then fed all these to an 8 input OR then to INT1 , and output them individually to the Port 1 (something more like the interrupt addressing in x86 architecture ,if i remmember correct). then trigger the timer 1 to detemine the delays , and read the spark number from Port 1 .

3- I didn't know where to buy and what i need for the suitable flash light to be triggerable at frequencies up to 20Hz assuming the 1200 RPM! (turn on/off fast, without much further glowing than the time supply is provided)

How do you think about my initial ideas ?

The whole thing will use a AT89S51 and an LCD , so hopefully it's on topic ;) .

Thanks for your valuable time.
Farshid J.H.

List of 45 messages in thread
Tachometer and engine timing tool      Farshid Jafari Harandi      08/13/05 22:06      
   Engine analyser      Russell Bull      08/13/05 22:44      
      RE : Engine analyser      Farshid Jafari Harandi      08/14/05 12:19      
         Engine analyser      Russell Bull      08/14/05 19:11      
            Xenon Flash Lights      Farshid Jafari Harandi      08/14/05 20:50      
               Xenon flash lights      Russell Bull      08/14/05 21:39      
                  Calculating RPM      Dan Adams      08/15/05 07:38      
                     RE: Calculating RPM      Farshid Jafari Harandi      08/15/05 14:10      
                  flash charge circuit      Farshid Jafari Harandi      08/15/05 14:16      
   Look at this then        Steve M. Taylor      08/14/05 07:15      
      I like it...      Farshid Jafari Harandi      08/14/05 12:20      
   Xenon      Neil Kurzman      08/14/05 16:51      
      Delay time < 10us      Farshid Jafari Harandi      08/14/05 20:31      
   Led Instead Xenon        Roberto Muņoz      08/17/05 08:02      
      Interesting idea, were I to make sutch a      Erik Malund      08/17/05 08:08      
         White is better for finding the TDC mark      Farshid Jafari Harandi      08/17/05 14:13      
            If white light is required and what I ha      Erik Malund      08/18/05 06:08      
               Good link      Farshid Jafari Harandi      08/18/05 14:07      
      Nice !!      Farshid Jafari Harandi      08/17/05 14:08      
         I do not work with white LEDs but with r      Erik Malund      08/17/05 14:30      
            White LED      David Smith      08/18/05 07:01      
               got curious and googled      Erik Malund      08/18/05 07:12      
               got curious and googled      Erik Malund      08/18/05 07:13      
               Hmm      Steve M. Taylor      08/18/05 07:35      
                  Sure it's not, but      Farshid Jafari Harandi      08/18/05 14:07      
                     New prototype circuit      Farshid Jafari Harandi      08/19/05 01:07      
                        I would recommend a constant current cir      Erik Malund      08/19/05 06:05      
                           Current regualtor      Farshid Jafari Harandi      08/19/05 10:02      
                              C2 may blow your LED, what is it there f      Erik Malund      08/19/05 11:19      
                              Led ON time      Russell Bull      08/19/05 22:51      
                                 6000 RPM      Farshid Jafari Harandi      08/20/05 12:42      
                                    6000RPM      Stuart Hall      08/21/05 01:06      
                                       Can't comment on that now      Farshid Jafari Harandi      08/21/05 14:30      
                  saw an article and while this probably      Erik Malund      08/18/05 14:12      
                     Thanks      Steve M. Taylor      08/18/05 14:33      
                        timing light      Russell Bull      08/18/05 23:09      
                           unanswered questions      Farshid Jafari Harandi      08/19/05 01:06      
                  White LED v Xenon tube      David Smith      08/19/05 01:19      
                     'difficult' to drive      Farshid Jafari Harandi      08/19/05 04:25      
                        Big LEDs      Steve M. Taylor      08/19/05 04:57      
                           So Thats it !      Farshid Jafari Harandi      08/19/05 09:59      
                              Who has said ir has to be just one, can      Erik Malund      08/19/05 11:21      
                                 C is for stability ?      Farshid Jafari Harandi      08/20/05 12:32      
                     I have no idea, but I have seen I do not      Erik Malund      08/19/05 06:13      
                        White LED 'drivers'      David Smith      08/20/05 14:31      

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