greggors84
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| posted on 31/5/06 at 03:09 PM |
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Cheap Speed Sensor Alternative
After finding out my speedo sensor wasnt working and not really wanting to cough up the £30 + p&p +vat that most places wanted. I thought i would
try a simple reed switch. I wasnt sure if the CAI one was anything special, but after finding out the way to test them is to connect it inline with a
bulb and connect across 12v, it seemed it was pretty normal.
I went to maplins and bought this
http://www.maplin.co.uk/Module.aspx?ModuleNo=4767&criteria=reed%20switch&doy=31m5
For £1.99 its just a simple door reed switch, it comes with 4 wires but only 2 of them are needed, on mine 2 had the ends stripped and it turned out
these were the ones i needed. Its pretty easy to mount, i drilled out my old sensor mount so the new reed switch would slide in and be held by
friction, just enough so I could set the distance to the magnets by hand, then i used some epoxy to hold it in place for good.
One thing i was unsure of was the reaction time of the cheaper reed switch, as the magnets will be moving very fast i wasnt sure if it would be able
to keep up with it. I just a had a test across my parents yard and it was wheelspinning across the grass at 30, which was the most i dared due to lack
of space!
I'm have the car rolling road tuned tomorrow, so will set the speedo up then and let you know how it copes at higher speeds.
Just though i would inform people of a +£28 saving to be made!
Chris
The Magnificent 7!
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muzchap
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| posted on 31/5/06 at 04:31 PM |
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Heh nice one 
Wish you'd told me about his earlier 
Good luck with the rolling road!
------------------------------------
If you believe you're not crazy, whilst everybody is telling you, you are - then they are definitely wrong!
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Johnmor
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| posted on 31/5/06 at 05:46 PM |
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Sound great.
I recently bought a cheap cycle computer from halfords £4.99. Comes complete with reed switch and tie wraps etc and its nice and neat.
May try that.
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irvined
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| posted on 31/5/06 at 09:24 PM |
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I used something like this from rs, worked a treat
http://rswww.com/cgi-bin/bv/rswww/searchBrowseAction.do?obs=sObs&name=SiteStandard&No=0&N=0&Ntk=I18NAll&Ntt=reed%20switch%20m6&
;Nty=1&D=reed%20switch%20m6&callingPage=/jsp/search/search.jsp&BV_SessionID=@@@@0190597871.1149110585@@@@&BV_EngineID=ccceaddhljeeiekc
efeceefdffhdhig.0&cacheID=uknetscape&Nr=avl:uk
http://irvined.blogspot.com
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RoadkillUK
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| posted on 1/6/06 at 10:20 AM |
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We have a Sigma BC1600 fitted to our car, has been on for some time now and it works a treat.
I was out in the car yesterday with SatNav and I checked the speedo against the GPS and it was spot on.
I'd recommend spending £10 - £15 on a cycle computer.
Roadkill - Lee
www.bradford7.co.uk
Latest Picture (14 Sept 2014)
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greggors84
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| posted on 4/6/06 at 09:03 PM |
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Update:
Had the car rolling roaded last week. He took it up to 110 in 4th, the speedo stopped at 70! My suspicions of the cheep reed switch not reacting fast
enough were true!
I will have to get one of those irvined suggested, only a few quid more but alot less than the CAI one. Just hope it comes in time for the SVA,
although am i right in thinking the speedo only needs to be accurate to 70mph?
Chris
The Magnificent 7!
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Dusty
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| posted on 5/6/06 at 01:11 AM |
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With a VDO speedo I am using the hall sensor from the middle of a mondeo speedocable. I think it was linked to the computer not the speedo in the
mondeo.
£5 from the scrappy.
[Edited on 5/6/06 by Dusty]
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Peteff
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| posted on 5/6/06 at 06:56 AM |
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am i right in thinking the speedo only needs to be accurate to 70mph?
Mine was tested up to the 100mph claimed top speed of the car at SVA so I wouldn't chance it.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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