Moorron
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| posted on 27/4/06 at 09:53 AM |
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speedo and hall effect sensor??
I have just been rewiring the car and have noticed a few things that dont look right, can anyone help?
My car is fitted with a smiths speedo, which is using a hall effect sensor off the prop. I am very sure its not a magnet sensor as if you pass any
metal under it the little led on it lights up, it also has a +12v feed, earth and signal wire. But i noticed its connected to the speedo 'magnet
input' wire and not to the 'hall input' wire. The smiths fitting instructions also say that one of the wires has to be connected to
+12 if using a hall sensor, which it wasnt.
It still worked wired up "wrong", but lost itself every now and then. Would i be risking damage if i wired it up to the instructions
instead of the original way??
would this stop the unit from loosing the reading?
also, another sensor (exactly the same as the above one) is used for the DG8 gear indicator, but it wont program (it doesn the first few gears only),
the dg8 uses a magnet input so is this the problem? if it is i will happily pay the £35+ for the optional magnet sensor from acumen who sell the DG8,
but i dont want to waste my dosh if its not going to effect it.
Any help would be great.
Andy
Sorry about my spelling, im an engineer and only work in numbers.
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Moorron
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| posted on 27/4/06 at 10:01 AM |
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PS. i re connected the battery last night thinking nothing would work, atleast thats ok....phew!
Sorry about my spelling, im an engineer and only work in numbers.
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TimC
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| posted on 27/4/06 at 11:37 AM |
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I'd be suprised if this is the case - any ferous metal will have some magnetic properties and therefore trigger the sensor if held close
enough...
I actually replaced the speedo one as I bashed it and I ordered a magnetic from Merlin Motorsport!
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Moorron
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| posted on 27/4/06 at 12:08 PM |
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actually i have only checked the dg8 one, but it looks identical to the speedo one. so i will double check tonight to see if it is a magnet one. The
dg8 one read the bolt heads off the driveshaft bolts????
doesnt the led work by reading an object, if they were both magnet ones how does the led turn on? when a threshold has been met?
im not entirely sure how they work, but i can only think from collage days that the magent ones output a waveform like a sine wave, something that
gets bigger and smaller, where a hall sensor is digital, its on or off (and therefor the led lights up). ??
these are the only 2 things that need wiring up now so tonight i will be over the moon or throwing spanners at the wall lol.
i suppose meeting other members at the w/e will help me.
So i might be there in your old car Tim, if not i will be hanging around the MK owners club.
Sorry about my spelling, im an engineer and only work in numbers.
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TimC
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| posted on 27/4/06 at 12:22 PM |
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No, both sensors read the magnets attached to the sprocket/prop adapter.
As for the science, my GCSEs were a long time ago!
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Moorron
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| posted on 27/4/06 at 01:41 PM |
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yes tim i agree but if u wind the dg8 one in it will pick up the prop itself and never see a gap. so thats why i am confused.
i did 2 years of electronics and electrical engineering and i get shocked many times a year. lol. i should know better.
it will get sorted one way or another.
Sorry about my spelling, im an engineer and only work in numbers.
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