Missing Tooth Detector

This processor process a trigger wheel signal and outputs a sync pulse when a missing tooth (teeth) is detected.


The DIGITAL signal comes to pin11.
At the end of the missing tooth/teeth, 4 pulses are generated:
– a positive and short pulse (10us)
– a complementary negative and short pulse (10us)
– a positive and long pulse (200us)
– a complementary negative and long pulse (200us)


  • Can use any kind of trigger wheel ie: 36-1 or 12-3
  • Input signal: DIGITAL +5v
  • Output signal: DIGITAL +5v
  • Output duration: 10 and 200us
  • Working range: From 1Hz to 800Hz with a 16-1
  • Working range: From 1Hz to 400Hz with a 32-1
  • Working range: From 1Hz to 200Hz with a 64-1


This microprocessor CANNOT use an ANALOG signal coming directly from the VR pickup!

If the signal is ANALOG:

It MUST first be shaped in DIGITAL form with a “VR conditioner” (MAX9936,LM3915,NCV1125,…)



2 thoughts on “Missing Tooth Detector”

  1. Came here from Vintage Honda Twins after seeing a link.
    Very nice site, easy to follow things around.
    I only have a 1979 Yamaha XS650 with electronic ignition and it was running fine when parked (2012) but knowing there is a site out there if I do need anything it great

Leave a Comment

Your email address will not be published. Required fields are marked *

Shopping Basket
Scroll to Top