lexus speedo to work properly in surf??

[dannyboy77]

vince dont know if you seen this thread? it would cost £160 to get the lexus speedo working properly, its a bit steep i know but i do prefer the lexus head up to the surf one hehe! do you know or anyone who reads this tread any one here that could the same?

http://www.lextreme.com/forums/showthread.php?t=13523

[gwh200]

Hey Danny. Is it possible to, instead of increasing the amount of pulses from 4 to 20, split each pulse 5 times. On the sewage works, there is a lot of interfacing required to read an analogue signal as a digital pulse. This is accomplished by using a simple interface that works over a 4-20 Ma range. It converts in the same way (I reckon), that you are looking for.

[BUSHWHACKER]

Have a read of this thread.......
http://www.yotatech.com/f161/1uz-fe-...24/index3.html
post 67.

[dannyboy77]

Have a read of this thread.......
http://www.yotatech.com/f161/1uz-fe-...24/index3.html
post 67.

thanks will do! may need another lexus speed sensor well the casing as i tried cutting the one you sent me up tried to join the two together some how but with no success . will see if i can salvage it though

[Apache]

Hey Danny. Is it possible to, instead of increasing the amount of pulses from 4 to 20, split each pulse 5 times.

Yes it is, and electronically it pans out as the same thing really. I'd have to get the books out, but I'm thinking edge triggered flipflop, so on the up transition and the down transition of each pulse, you get a pulse. ie, each pulse provides two pulses at the output. Some logic and some lateral thinking should see you arrive at the pulse count you need.

[blackpoolsparks]

Yes it is, and electronically it pans out as the same thing really. I'd have to get the books out, but I'm thinking edge triggered flipflop, so on the up transition and the down transition of each pulse, you get a pulse. ie, each pulse provides two pulses at the output. Some logic and some lateral thinking should see you arrive at the pulse count you need.

That wouldn't be so bad if you wanted to divide it up evenly, but he wants a 20 to 4 ratio ??? and divide by 5
how to do that ?

[Apache]

That wouldn't be so bad if you wanted to divide it up evenly, but he wants a 20 to 4 ratio ??? and divide by 5
how to do that ?

Hadn't got that far, but with some judicious use of counters and logic, it should be doable.

[an1mal_69]

Sack it.!!

Get an aftermarket dash..that's the way im gonna go I think. SPA do a really nice one (used in some of the Noble sports cars) but it's about £800, cheapest top drawer one. You've also got Stack, but there mega bucks.

Found some half decent ones in the 350-500 range, bear in mind they do all your pressures and temps too so no need for extra gauges.

[blackpoolsparks]

Sack it.!!

Get an aftermarket dash..that's the way im gonna go I think. SPA do a really nice one (used in some of the Noble sports cars) but it's about £800, cheapest top drawer one. You've also got Stack, but there mega bucks.

Found some half decent ones in the 350-500 range, bear in mind they do all your pressures and temps too so no need for extra gauges.

Yeahhh!
Heres the baby you want.

http://www.stackltd.com/steeringdash.html

[Ambobeer]

What voltage are the pulses?

May be an option to convert using a micro controller. From memory they're about £2 each.

Just need someone to program it

[Apache]

Thats where the money is if you dont know someone.

Thinking about it some more, I was thinking simple pulse counter to voltage conversion, then voltage to frequency conversion, calibrating the voltage into the V-F converter to give 20Hz (20 pulses) square wave for 4Hz (4 pulses) in. You can shape the output pulse to whatever you like pretty simply then.

I'm sure there's a million ways to skin that particular cat - sounds just right for GCSE electronics student project actually

[dannyboy77]

im lost now any one speak english around here

[an1mal_69]

Been working on putting my trans' together today. It's the first time I've seen the speedo set-up on the Lex'..

The spd sensor has a 20 pole magnet (hense your 20 pulses) which rotates inside the sensor, driven by the worm gear. I was thinking along the lines of running a 20 prong trigger wheel and just wiring a hall effect sensor similar to the other spd sensor (with the 4 prong wheel).

But this is where it gets difficult, the mag-wheel sensor takes the 20 pulses and converts it to a 12v square wave for the clocks to process.

So the key still lies with the trigger wheel in my opinion, then a box to convert your signal to the 12v sq/wave for the clocks.

How've you done yours Vince.?


Edit: diagram should make it a bit clearerer..

[dannyboy77]

hi Nick hows the transplant going! if you need an extra pair of hand just let me know!

still a bit lost but thanks for trying to explain! i work with electrical engineers so will show them this thread and get them to translate into laymans terms between them and you we might get this sorted!?

[an1mal_69]

It's going..just slowly that's all, soooo much to do. Im just chipping away at it at the mo, in a kind of chaotic and fragmented manner but I can see points where it's all going to come together.

Need to start fabrication for the axle links, engine mounts and cross member soon and there's a good few hours going to be tied up there, after that it's test fitting and getting it all to work