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Date: 02/13/03 at 12:25 PM
Posted by: Brian Snell
E-mail: bsnell@lara.on.ca

In Reply to: Re: Dunce question posted by andrew on 02/12/03 at 9:41 PM:

Hello again Andrew,

I think that trying to install microswitches, etc, to be actuated by the gearshift lever is an exercise in futility in the system you describe. If there was a way to get inside the gearbox and place switches there then it could work. However, for 6 different gears I think that this would be a major undertaking and also might not be do-able.

I am wondering if a more elegant solution is called for. If you were able to install a sensor on the input shaft, and another on the output shaft, a "gated counter" should work. The input sensor could be a slotted IR sensor which is actuated once each rev by a piece of matte-black painted scrap metal attached to the input shaft somewhere, or even a magnet switching a Hall Effect chip. reluctance coil, or even possibly a reed switch. This would provide a short output pulse once per rev and be used to reset a binary counter. The output shaft would require a similar setup but would require more pulses per rev, so a slotted encoder-style perforated disc with another IR interuptor sensor would be required here. The output pulses from this sensor would clock the counter . In any particular gear, for every single rotation of the input shaft the counter would provide a binary "word" output, which is then easily re-worked to provide whatever logic would be necessary to light the visual LED for that gear. The speed of the shafts don't matter, since input and output rotations are in a locked ratio. The only drawback would be that until the shafts are rotating you would not know what gear is already selected.

The logic decoding , and the number of slots in the output interruptor disc are dependent on the gear-ratios for each of the 6 gears. I would think that some ratios are greater than 1:1 and some less than 1:1. It may not be necessary to have a full BCD decode either -- as long as there can be 6 individual but different counts on the least number of "digits". If you can advise what the 6 gear ratios are I can tell you how many slots you would need for the output disc, as well as details on the decoding for the LEDs if you feel this would be helpful.

Regards,

BS.

Follow Ups:

  Re: Dunce question andrew   Posted at: 02/14/03 (6)

  Re: Dunce question Brian Snell   Posted at: 02/14/03 (5)

  Re: Dunce question andrew   Posted at: 02/23/03 (4)

  Re: Dunce question Brian Snell   Posted at: 02/24/03 (3)

  Re: Dunce question andrew   Posted at: 02/27/03 (2)

  Re: Dunce question Brian Snell   Posted at: 02/28/03 (1)

  Re: Dunce question andrew   Posted at: 02/28/03 (0)

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