gear cut/shift setup H pattern using strain gage gear knob

[POPWORTH]

Many thanks again Steve for info. Does anyone over here do the microswitch gearknob? I've tried to contact sqs but with no luck. Could i use a geartronics gearknob? Or does the voltages make a difference? 0.5v-4.5v biased in the middle at 2.5v. Or does the fact it differs in voltages mean I couldn't use it on a h pattern for only going up gears?

[stevieturbo]

It was a couple of years ago I bought mine from SQS.

Dont recall there being any difficulty contacting them, and it was quick to arrive. I'm not aware of anywhere else selling such a thing.

For an upshift cut, as far as I know it wants to see a rising voltage, so a load cell that will go up/down....I'm not sure if that could be used here. Although Kiel seemed to suggest he got his to work, but I've no idea how.

I never really looked into it too much as I didnt have a load cell so it may be possible.

[POPWORTH]

Thanks again for answering my questions stevie, Sqs have just replied, which gearknob would I require the basic one which is 2 switches both giving the same signal. The one way which is 1 switch only one way, or the 2 way which is 2 switches one switch for up gears output one down gears output. I'm guessing it's the basic one as would give rising voltage both ways? Just wanted to confirm. Many thanks.

[stevieturbo]

Again with it being an H pattern, you'll be doing both motions, but both for upshifts.

So I dont see how a 2.5v load cell or other type would work that gives a Hi/Low signal for one direction or the other could easily work for this. If it can be done, I'm all ears though as would be curious.

Mine is just the basic switch, it comes as an M12 fitment

[ATOMIC]

Including the strain gauge (shear beam load cell would be best) you really would need a gear position sensor. With a H pattern you would need varying cut times per gear as the cut times inline with the gates ie 1-2, 3-4, & 5-6 etc will vary across the gate (2-3) - (4-5). As mentioned you will need a gear position sensor and for an H pattern box you could use a stringpot sensor. I know West Surrey Racing did this with their 5speed H patten gearboxes in their BTCC BMWs using the Variohm MTA series cable-extension transducer.

[stevieturbo]

Including the strain gauge (shear beam load cell would be best) you really would need a gear position sensor. With a H pattern you would need varying cut times per gear as the cut times inline with the gates ie 1-2, 3-4, & 5-6 etc will vary across the gate (2-3) - (4-5). As mentioned you will need a gear position sensor and for an H pattern box you could use a stringpot sensor. I know West Surrey Racing did this with their 5speed H patten gearboxes in their BTCC BMWs using the Variohm MTA series cable-extension transducer.

You do not need a gear position sensor, but yes if you could implement one reliably, it would allow full closed loop shift cuts, which would be a huge improvement over open loop.

But for open loop it is not needed as long as the ecu has the info to calculate gear.

And still not sure how a load cell would work here, at least not a 2.5v cell that goes Hi/Lo with fore/aft movements as I can only see the shift cut activation from a single trigger level threshold. Although again I stand t be corrected if it can do shift cuts with both a high and low voltage trigger from such a load cell.

It would be interesting to see how those H patterns are configured to create a gear position sensor though ?

[ATOMIC]

When I said "you really would need" I simply mean...ideally. It's worth doing right.

You would use the load cell to simply tell the ecu a shift is being initiated, the position sensor would be used to tell the ecu when the shift has been completed. You could do away with a the strain gauge and rely on the cable-extension transducer but it would be better to use one.

The cable-extension transducer is simply attached to the transmission tunnel (at a slight offset) and the cable then attaches to the gear-lever. This ensures each gear position returns a different position reading without needing precise alignment.

[POPWORTH]

I ordered my gear knob through SQS and it arived the NEXT day from Prague! How awesome was that. So what Atomic is saying if i get this right is that the sqs microswitch knob can be used to start a cut as it has the same output in both gearstick directions, but if you set up and calibrate the cable sensor he has shown to each gear you can use this to tell the ecu when its in the next gear to stop the cut, meaning you can use closed loop shifting. I was going to try setting the gear configuration that you spoke about Stevie and fitting a wheel speed sensor at the front and inputting the gears and drive etc. Do you think stevie that one of those cable sensors could be configured to work? It sounds like it may work if could be configured? Im all ears on this as would like to do it right first time and if i could get it closed loop would be awesome as would work alot more effeciently. Look forward to your feed back.

[stevieturbo]

Interesting little sensor that.

Only seeing the pics now ? Dont think they were there a couple of days ago ?

What sort of money is that sensor ?

I had considered something like that but with a linear rod type sensor, but to make it all neat and hidden away would have been almost impossible. The string sensor could be a little more discrete

[stevieturbo]

I ordered my gear knob through SQS and it arived the NEXT day from Prague! How awesome was that. So what Atomic is saying if i get this right is that the sqs microswitch knob can be used to start a cut as it has the same output in both gearstick directions, but if you set up and calibrate the cable sensor he has shown to each gear you can use this to tell the ecu when its in the next gear to stop the cut, meaning you can use closed loop shifting. I was going to try setting the gear configuration that you spoke about Stevie and fitting a wheel speed sensor at the front and inputting the gears and drive etc. Do you think stevie that one of those cable sensors could be configured to work? It sounds like it may work if could be configured? Im all ears on this as would like to do it right first time and if i could get it closed loop would be awesome as would work alot more effeciently. Look forward to your feed back.

For closed loop you would need some way of the ecu knowing what gear. But that string sensor as long as you can get it to give an increasing voltage for each gear should work fine ( and a sensible gap between voltages...ideally a fairly even gap )
So the string sensor would largely govern the closed loop aspect and tell the ecu which gear. On that front you probably would not need a vehicle speed sensor to calculate gear..but for many other features you want vehicle speed to be known so it would be silly not to have it.

The only caveat there is it wont know neutral which on a sequential box would have it's own voltage, so that might confuse a little but when moving I guess it shouldnt be a problem for 1 and upwards shifts.


I think it could be configured to work ok as long as you can get a nice even voltage step between gears and that the string sensor itself is reliable and able to cope with fast stick movements ok.