Sat nav

[IBROKER]

In the ongoing saga with my sat nav.

I finally managed to find the speed pulse wire
behind the speedo, black and red cut dead going nowhere
about 6 inches long.

However! If you actually connect said wire to the sat nav unit the sat nav works fine and registers the pulse
but!! The speedo stops working, disconnect and the speedo is fine.

Any thoughts from anyone (FACTORY??)



>>> Edited by ibroker on Friday 11th June 08:58

[m12_nathan]

2 Years? That'll be a record for you won't it?

I never bothered with the speed pulse, I just use the GPS singal on its own.

[adparker]

Having my Pioneer ANH-P9R fitted tomorrow so wouldn't mind knowing too!

[ibroker]

Nathan

I take your point!!

It will not work on the gps signal alone, tried that.

adparker. The Pioneer unit your having is the same unit I have. Perhaps you could let me know how you get on

[joust]

Googling found

www.gpsw.co.uk/details/prod836.html
Means you don't need to rely on the car one

www.cel-direct.com/navi2.asp?s_group=accessories

www.powerengineering.co.uk/acatalog/car_gps_alpine_NVEK300.htm

etc.

[Lynton]

I Have a Blaupunkt unit and used the same wire for the pulse - Speedo still works fine. Sat Nav works fine. The only thing | have had trouble with is the remote control unit fitted on the steering wheel, this will be the third replacement. Multi-changer also works fine.

Parrot bluetooth 'phone kit is fine to listen to but the caller has difficulty hearing what I say.

Best regards,

Lynton

[adparker]

IBROKER said:

However! If you actually connect said wire to the sat nav unit the sat nav works fine and registers the pulse but!! The speedo stops working, disconnect and the speedo is fine.

Did you ever manage to suss out this problem? The guy fitting my ANH P9R is having exactly the same problem!

[joust]

I'd imagine (without looking or knowing the exact details) you are suffering from an "open collector" problem on the ouput of the speed pulse. Basically this is a system design that doesn't have any internal "pull up resistor" within the output circuit and relies on whatever you attach to perform the "pull up" to +5V/+12V.

If I've read the symptoms correctly you are suffering from a "wired-AND" issue. What you need is a "high impedance repeater" circuit in there between the speedo and GPS system, or something to sort out the "wired-AND" issue.

You therefore have three choices from memoty (although it's nearly 9 years since I played with OcE circuits!).

1) Fit a system as I indicated above that gives an independant pulse to the GPS (the links are above)
2) Get your fitter to source the appropiate series pullup resistor to sit the Vfe output at the right level (this will probably take a lot of experimentation), although you may find it's an open drain output and hence you'll need to do the same to ground.
3) Change satnav manufactuer to a company that doesn't require any source current on the speedo input

J

[adparker]

I'm sure you're right Justin but i've just been told that a speed pulse amp will do the trick! Will post after it's fitted tomorrow

[joust]

Yep - that's the same thing! Sorry - it was late last night and I obviously wans't in a "keep it simple" mode!

The amp will have a high impedance input and hence won't drag down the signal.

J

[ibroker]

Andy

I take it from this post you received none of my emails. We seem to have a problem here with anyone on AOL. Any mails sent just bounce back.

To answer your question. No I did not sort the problem.
Last night I inserted a diode in the speed pulse to restict current just one way. No good speedo still stops working.

Was your car at Kerridges 2 weeks ago. I picked mine up
from its first 1000 mile service and one just like yours was there. Where R U in essex. We could meet for an outing

Justin

Thanks for your input. Very technical. Problem is having spent £1000 on the unit its a waste to just dump it.

[joust]

ibroker said:

Thanks for your input. Very technical. Problem is having spent £1000 on the unit its a waste to just dump it.

The foolproof way is to buy one of the speedo pulse generator kits (they are inductive - mount it near the wheel), although any hi-impedance pre-amp will probably do the trick (check out Maplin - they have loads of <£10 pre-amp kits - find one that has a close input voltage to what's on the speedo pulse and you should be fine) - search for "amplifier" at www.maplin.co.uk and you'll find loads!

[adparker]

ibroker said:

Andy I take it from this post you received none of my emails. We seem to have a problem here with anyone on AOL. Any mails sent just bounce back.

No i didnt receive any of them which i thought was a bit odd!

ibroker said:

Was your car at Kerridges 2 weeks ago. I picked mine up from its first 1000 mile service and one just like yours was there. Where R U in essex. We could meet for an outing

I did go to Kerridges for my 1k service but that was back in October so it wouldnt have been me. I'm near Chelmsford, think theres one or two owners in the area, Billywiz is definately near by

[adparker]

Well, after 2 hours yesterday playing about with the speed pulse amp and numerous phone calls, still no joy. There is a slight chance the amp could be faulty so thats going back and we'll have another go next week. If that one doesnt sort the problem out either then i havent a clue what to do next!

[joust]

Buy one of these!!

www.gpsw.co.uk/details/prod836.html

J

[adparker]

joust said:

Buy one of these!! www.gpsw.co.uk/details/prod836.html J

Yep, i remember now, the chap fitting it did suggest one of those kits as the next course of action, apparently theyre pretty accurate and reliable, somethings got to work!

[adparker]

Just to update this saga and say that the speed pulse generator did the trick and i finally have satnav in my car!