Non AJS Electrical Question

[ericblincoe]

Hi. Les, this is the THIRD attempt this morning to get a post out !!
This effort is much truncated compared to the other two .. just in case it too fails !!
It looks to me that the counter is a shift register triggered up or down by the pulses from the gear lever.
The gear lever needs to be displaced fully up or down to generate a pulse, slipping into neutral from say 1st will not generate a pulse.
A neutral pulse could be generated by connecting a relay to the neutral indicator switch, the other wiring to the switch would remain.
This relay would be fed from the ignition and earthed via a series capacitor, through the switch, the relay would pull up on operation of the neutral switch and drop out shortly thereafter when the cap has charged, the relay contacts would only be connected to the counter reset input and 0v and would therefore provide a clean pulse.
The pulsewidth would be dependant on the cap. size and the cap. would need a bleed resistor to enable the charge to decay between operations.
Whether the transient neutral contact between 1st & 2nd would effect matters remains to be seen.....

...... as does the ability of this post to escape .....

[leswaller]

Hi Eric
Thanks for the update which has been successful!
I think you are correct in your assumptions the gear lever makes a full movement when going from 1st to second via neutral, but just slipping into neutral does not trigger the '0' on the indicator which I think is due to the 1.05v that remain on the indicator switch lead when in neutral. Moving through the gears applies 12v to the lead and they all indicate ok when the gear lever triggers the sensors.
I will try your idea with a relay using a capacitor and resistor. I have tried the relay on it's own and this of course gives a constant earth which doesn't work as it doesn't have time to disconnect before a gear change is registered.
What values are you thinking of?, after a bit of head scratching I have come up with 500uF and 10K which I think might give a pulse of about 1 sec, what do you think?

[ericblincoe]

Hi. Les, I'm on line again then !!
The component values for slugging the relay depends on the resistance of the coil, rather than fanny about with calculations I would go with trial and error !
Thinking about the physical actions of the gear lever, may be 1 sec. is a decent pulsewidth for the sensors, so the same should be OK for the reset
pulse.
As well as slugging the relay try to match the gearchange pulsewidth, also consider its recovery time. decided by the size of the bleed resistor I would have thought about 1 KOhm is a good place to start, 12mA should not hold the relay up and should discharge the cap quite quickly.
If the recovery time is too long you may lose your count when in slow traffic!

[leswaller]

Ok, thanks I will give that a go and let you know at the section meeting how I get on

[aobp11]

Les, I think the solution with a relay is too "mechanical". My suggestion is "solid state", much easier and more robust. The type goandstop you mentioned is in the same series, so basically the details I pointed to are still in order I think. Also the wiring circuit in in your reference tells that the reset input is connected to the neutral switch. So that input needs no short pulse; the 0 V level is maintained as long as the neutral switch is closed. It could perhaps be that the neutral switch is still closed when your gear level passes the sensor while selecting first or second gear. Then the reset input probably will overrule the lever signal. Perhaps you can check that your bike's neutral light goes off before the lever reaches a sensor. However, a problem here would only affect switching from neutral to first or second gear, while higher gears would be indicated one off.
My suggestion was as follows. Solder 2 general purpose diodes in series. Don't connect the wire coming from the neutral switch directly to the reset input. Instead solder the diode assembly between wire and input, with the direction of conduction ("arrow") pointing to the input. Also connect a resistor between input and earth. I guess a resistor value 2.2 kOhm is small enough to activate the input when the switch is closed. You can try larger values as long as the neutral switch still works as desired.
BTW the reason for a reset input is correctly given by Eric.
You should be able to program the highest possible gear indication in the unit. Then by accident trying to select a still higher gear with the lever will not disturb the counter. (I was afraid of that.)

Albert

[leswaller]

Albert,
So many suggestions that I am now getting confused. Why 2 diodes in series? why not just 1? What kind of value should they be?
What happens when the bike is in gear? as during that time there is 12v on the neutral switch line even though it is not going anywhere due to the neutral switch being open.
Would I not still need a relay with normally closed contacts for when the bike is in neutral and open when 12v is applied in order to protect the diodes?

[Jonny Astro]

I've been following this for a while - What a palaver! Is having confirmation of which gear you are in really going to be worth all of this messing around ?

I had a gear position indicator an a GS650 many years ago - once the novelty wore off I didn't even look at it...

Jon

[leswaller]

Jon I am trying to fit this on a Kawasaki with 6 gears and it is very easy to get confused as to which gear you are in. Also I am determined not to let this beat me.

[aobp11]

So many suggestions that I am now getting confused. Why 2 diodes in series? why not just 1?

In conduction the voltage drop across 1 diode is about 0.65 V, less than 1.05 V. For 2 diodes in series the drop is 1.3 V. This insures that the diodes won't conduct current to the reset input when in neutral. The resistor can pull down the reset input voltage towards earth.

What kind of value should they be?

Any general purpose will do. Popular and robust for instance is 1N4007 (overkill). Current won't be more than a few milliamps.

What happens when the bike is in gear? as during that time there is 12v on the neutral switch line even though it is not going anywhere due to the neutral switch being open.

The neutral light is between switch and 12 V. A slight current will flow via that light and the diodes into the reset input and also via the resistor to earth. Since the bulb resistance is small (when not a LED) the reset input voltage will rise to about 10 V or so. That's fine.

Would I not still need a relay with normally closed contacts for when the bike is in neutral and open when 12v is applied in order to protect the diodes?

No, not at all.

Albert

[G15 Roy]

Jon I am trying to fit this on a MAtchless with 6 gears and it is very easy to get confused as to which gear you are in.

Les I thought you sold the six speed matchless special you had.