To all the clever bored people.

I fancy a little vehicle project to break up the DIY sessions, & top of
the list is a manual sequential gear shifter for the Jeep. Just because.

The (automatic) box is controlled by two solenoids, as follows:

Gear Solenoid #1 Solenoid #2
1 On Off
2 On On
3 Off On
4 Off Off

Now I know zilch about electronics, but I'm sure this must be possible
with a digital joystick (moment switch) & a bunch of latching relays.
I.e. flick the joystick up once & sol1 is switched on. Flick it again &
sol2 is switched on. Flick again & sol1 is switched off etc. However I
have no idea how to wire this up, or how it would 'know' what gear it's
in & therefore which relays to fire & in which direction when going up
& down the box. Sooo...

[1] Is it possible?

[2] Any tips on wiring diagrams?

 

No
It should be pretty simple using some basic logic gates to make this happen.

But, how will you select neutral?

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That's a good start.

I'll use the main lever for neutral, reverse, park etc. The sequential
shifter will just be switched on & used in Drive when I'm in the mood,
or want to hold a particular gear off-road or going up/down steep hills.

 

It's probably possible using relay logic, but I wouldn't know how.

I've done stuff like that before using an eprom to build a finite state
machine, but these days it would probably be more fun with a little
microcontroller and then you could sense other stuff like rpm and road
speed and build in some intelligence.

Probably with the original control IWHT.

 

OK. You need a counter from 0 to 3, or 1 to 4 and some drivers to move
the solenoids. It's been *so* long since I've done any of this, there
may be other ways to do it.

I'd use a couple of switches, that you may be able to adapt from some
kind of joystick. I'd set it so that pressing up set the output high,
momentarily, and pressing down set it low.

You *probably* need to debounce that and feed it to your counter. That
would then make each of 4 pins high as you increment or decrement the
counter.

Each one of those pins on the counter will then trigger some kind of
logic gate to drive your relays / solenoids.

The last bit is *probably* easier to accomplish using some kind of PIC
these days, but they are a bit new fangled for me.

If I *could* give more help, I would, the best I can say is it is
certainly doable.

No doubt someone will be along soon to explain exactly how and then
someone else will be able to make it break light speed while doing a
rolling stoppy and proving the existence of the Higgs-Boson

--
Catman MIB#14 SKoGA#6 TEAR#4 BOTAFOF#38 Apostle#21 COSOC#3
Tyger, Tyger Burning Bright (Remove rust to reply)
116 Giulietta 3.0l Sprint 1.7 GTV TS GT 3.2 V6
Triumph Sprint ST 1050: It's blue, see.
www.cuore-sportivo.co.uk

 

Blimey. This
http://www.electro-tech-online.com/...riggered-2-bit-binary-counter-trannyschem-jpg
is the kind of thing I was thinking of.

I'd be nervous of power glitches etc. making impromptu shifts from 4th
to 1st though.

 

No. It's not an uncommon request though.

 

Complete Greek to me!

 

Have a look at the controller Lego make.

Years since I looked but sounds like the sort of thing
it could do. Easy enough to program for children

http://en.wikipedia.org/wiki/Lego_Mindstorms

 

Good man, crack on ...

ISTR someone in the difflock (I think) forum doing something similar
last year or the year before, sorry can't be more specific as I'm going
on memory, but might be worth a look or a question, they're pretty
knowledgable people. Homepage here ...

http://forum.difflock.com/

 

What you have there is a two-bit Gray code. This is designed
so that only one of the bits changes on any transition, avoiding any
momentary change to an undesirable state if two bits _don't_ change in
perfect synchronism (e.g. in a rotary position encoder).
http://en.wikipedia.org/wiki/Gray_code -- see code at top of page.

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KotPT -- "for stupidity above and beyond the call of duty".

 

If you encode it into a 2-bit number AB (0=Off=0 V, 1=On=12 V) like this:

then you can see that Solenoid #1 is NOT A, and Solenoid #2 is A XOR B.

So... If you have a 2-bit up-down counter AB=00<->01<->10<->11,
#1 can be driven directly from 12 V off the NO contact of a relay whose
coil is connected to A and ground and #2 can be implemented in another
relay by the cunning trick that a relay coil is polarity-independent.
You wire the coil up to A and B and the NC contact only opens to 12 V when
A and B are in opposite states.

First, find your 2-bit up-down counter... But there are two other
difficulties: You have to have the state machine enter a known state when
you enter the paddle-driven condition (you have to bypass Drive so it's
still usable, and you can't have it entering whichever gear it was last in
in case that was inappropriate; otherwise you have to be able also to read
the current state of the solenoids) and you need extra logic to make sure
that count-down can't happen when AB=00 and count-up can't happen when AB=11.

This could get expensive...

--
Ivan Reid, School of Engineering & Design, _____________ CMS Collaboration,
Brunel University. Ivan.Reid@[brunel.ac.uk|cern.ch] Room 40-1-B12, CERN
GSX600F, RG250WD "You Porsche. Me pass!" DoD #484 JKLO#003, 005
WP7# 3000 LC Unit #2368 (tinlc) UKMC#00009 BOTAFOT#16 UKRMMA#7 (Hon)
KotPT -- "for stupidity above and beyond the call of duty".

 

So buying a kit for $170 might not be a bad idea then?

 

I can't help you with the electronics but I have a couple of Dupar digital
joysticks which you're welcome to if you decide to have a go at this
project:-

http://www.rula.pwp.blueyonder.co.uk/images/joysticks.jpg

Total height 130mm, face plate 65mm square. Each one has four on/off
switches (err... obviously). I'm told they fell out of some sort of control
panel at Dowty's. They're currently sitting on my desk in Gloucester.

 

Yup.

But as others have pointed out it will be easy to do (£20 or so for the bits)
easily. To do it safely will need more, as you really *really* don't want it
to suddenly change down to 1st from 4th.

That's where the complication comes in.

 

When I were a lad I had a sidevalve Hillman Minx with a 3 speed column
change. It was rather too easy to change down from top into reverse, it
actually went in rather easily but when I let the clutch up my
overtaking manoeuvers became very interesting rather quickly.

It did not take long for motor manufacturers to put the gear lever back
down on the floor where it belongs and front bench seats became history.

 

Wow. You had a mkI, made in 1932/3? The post 1934 mkII had a 4 speed
box.

Really. Funny how Vuaxhall were still making bench seat cars 30 years
later. We had one of these for a while when I was a kid
http://en.wikipedia.org/wiki/Vauxhall_Cresta#Cresta_PB

Well done. No drop in your standards for 2010.

 

Not the cresta, my father had a victor 101 with a bench seat and
column change. Not exactly sure when but I guess it was c 1971, didn't
last too long suffering terminal tin rot and was replaced by a triumph
PI, another piece of unreliable automotive junk.

Heh

 

Ooh yes please, reckon they'd be perfect if I replaced the knobs with
something a bit less 1950s. Would you be willing to post them if I
covered the cost? Or failing that, are you anywhere near Gyp?

 

Lovely, consider yourself hired! Sounds like a good excuse to finally
check out that village pub.