SAT NAV for Chimaera?????
Discussion
Just fitted a Sat Nav unit in my Chim and discovered that whereas most modern cars have a link for speed in with the radio's normal wiring loom, the TVR doesn't. I therefore need to hook up a 'Speed Pulse' from the speedo for the nav to work.
Has anyone done this? Does it require a convertor at all or is it a direct link? I'm going to get a proper ICE place to do it for me but none of them seem to know anything about a TVR's speed pulse!
Any help greatly appreciated
Cheers,
Gaz
Has anyone done this? Does it require a convertor at all or is it a direct link? I'm going to get a proper ICE place to do it for me but none of them seem to know anything about a TVR's speed pulse!
Any help greatly appreciated
Cheers,
Gaz
The following is based purely on guess work 
... I'd be surprised if you need to do any kind of signal conversion. It would be daft to build a sat nav system that couldn't (a) calibrate itself to detect the pulses and (b) work out how the pulse frequency relates to speed by comparing the pulse frequency to its own GPS-based speed measurement.
Assuming the speedo itself converts pulse frequency to a needle deflection, then you should be able to pick up the pulse stream from a terminal on the back of the speedo. Worse case scenario, and you do need to muck around with the pulse's frequency or voltages, you could do this from scratch with bits you could buy at Maplins for about a tenner.
... I'd be surprised if you need to do any kind of signal conversion. It would be daft to build a sat nav system that couldn't (a) calibrate itself to detect the pulses and (b) work out how the pulse frequency relates to speed by comparing the pulse frequency to its own GPS-based speed measurement. Assuming the speedo itself converts pulse frequency to a needle deflection, then you should be able to pick up the pulse stream from a terminal on the back of the speedo. Worse case scenario, and you do need to muck around with the pulse's frequency or voltages, you could do this from scratch with bits you could buy at Maplins for about a tenner.
I've had two Sat Nav systems installed into my Cerberas but not my Chimp. I will assume that they are the same.
You do in fact need a speed pulse...and not only that, you also need to mess around with it because...TVR use a non standard version that uses a high range. I don't know the full details but it goes something like this (very roughly). Normally they give off somewhere between 40 - 80 pulses in any given period...however the TVR version gives off between 600-1200 in the same period, so I needed to play with it for a while.
I was using the Alpine DVD Nav system in cases and once it had settled into play it was fine...it does take a while to learn though.
I am happy to chat you through it if you want (e-mail me your number).
Oh yeah...and good luck!
You do in fact need a speed pulse...and not only that, you also need to mess around with it because...TVR use a non standard version that uses a high range. I don't know the full details but it goes something like this (very roughly). Normally they give off somewhere between 40 - 80 pulses in any given period...however the TVR version gives off between 600-1200 in the same period, so I needed to play with it for a while.
I was using the Alpine DVD Nav system in cases and once it had settled into play it was fine...it does take a while to learn though.
I am happy to chat you through it if you want (e-mail me your number).
Oh yeah...and good luck!
I've got a portable Sat Nav, a Garmin Street Pilot. I used it on my Motorbike, and in my other car. There is no place to put it in the Chim, but my son held it while I drove. At 100mph on the Car, the Sat Nav was reading 99mph. Not too bad I reckon
Of course this speed was on a local track, I'd never be so irresponsible on a road
Of course this speed was on a local track, I'd never be so irresponsible on a road
You can get a pulse from the speedo but on my griff it doesnt work below 8mph!My Rangie doesnt work below 3mph. You can buy a converter but these do not start until 2-3 mph. Its surprising how far out it will be after crawling in traffic. I have a hall effect ic sensing a small magnet on the drive shaft, absolutely 100% acurrate. Clarion do a system that requires you to magnetise half the tyre and then the sensor sits nearby, the trouble with these is after around 95 mph they become a little inacurrate.
david beer said: Gaz
did you get sorted?
Almost but not easily! Phoned around a few places. None of them knew anything about TVRs. Two couldn't find out the answer within 5 days, and didn't know where to look, so I told them to forget it. Two actually told me the fitter would refuse to work on my TVR
because of the 'complexity' and 'difficulty' of them. My last call was to In Car Solutions as recommended by Tonyrec - and they were top class! Had worked on TVRs before, and were familiar with the unit I am fitting, so they knew all about it. So I've booked to leave it with them on Tuesday for two days while I'm away in Milan!
Cheers all for the advice, and cheers to Tony
for the heads up on the Welwyn place. I'll let you know if the quality of the work is as good as their knowledge and service when it's all done!
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