Tacho for 1 cylinder 2 stroke

Discussion in 'Electronics & Electrics' started by heavywater, Mar 13, 2012.

  1. heavywater

    heavywater Member

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    Hey,

    Just wondering if anyone has an idea of how I could build a tachometer for my bike engine using maybe seven segment displays (preferably 0 - 9,999RPM) ?

    Thanks.
     
  2. paulvk

    paulvk Member

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    You use the pulse from the spark plug. This is the easy way as you only need a small pulse transformer cliped around the lead to detect it. I think silicon chip had one as a project search their site for it.

    Regards Paul
     
  3. mike-s

    mike-s Member

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    Remember if you do this it will be a compromise between fast refresh speeds and ease of readability of the numbers onscreen. Silicon chip mag had an article about making this very thing a few years ago. They may have plans/pcb's for this. Another alternative is maybe altronics if they are still around, they had a lot of kits in their cat'n'dog,uhm, catalog.
     
  4. OP
    OP
    heavywater

    heavywater Member

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    Thanks lads i'll check those out :)
     
  5. dualmassager

    dualmassager Member

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    Most tachos off the self are for 4-stroke, so be careful. Most of these tachos just hook up into the ignition source and measure the frequency.
     
  6. aXis

    aXis Member

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    It might sound overkill, but if you're going to build your own I'd reccomend using an arduino and a character LCD display. The wiring is quite simple, and you'll have more flexability in the display. You could also display more than just RPM, eg battery voltage & temperatures.

    The Character LCD's on ebay are dirt cheap and very readable. I'd go for one with few lines but larger font - search for "Character LCD large" - I can see there is a 16x1 with 8mm characters here for only $7.

    Programming would also be dead easy - have a regular 1 second timer, count the number of pulses between the start and end of the timer, then update the display.
     
  7. mike-s

    mike-s Member

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    Configure it for use with a twin 4 stroke, problem solved.
     
  8. ywn

    ywn Member

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    i use one of theres on my rotax http://www.alfano.com/home.php

    it will tell u speed if u set up the gering and wheel size as it works on revs to determen the speed ( so when idling it will have a seepd reding but once moving its will be fine . it has water temp sensers
     

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