When i bought my second hand speedo it didnt come with one of those input sensors. Presumably its just a small coil which generates a pulse when the magnet goes past?

Do maplin's sell anything which would work?
I'm buying something else on there and thought i would be nicer to share the delivery cost.

Can anyone help?

Chris

Ideally you want to know what signal the speedo is expecting. There are lots of different types-

Reed relay
Hall effect
Variable reluctance

1 and 2 supply quite big signals whilst 3 supplies signals in the millivolt range. If its expecting 1 or 2 and you give it 3 it just won't work, if it's got a big amplifer on the input stage (ie expecting a VR signal) and you give it full voltage the amplifier might start complaining...

If you can tell from a picture, then it's one of these:

Picture

Thanks

that looks the same as mine, input on mine is via a 12vdc 3 wire proximity switch. Maybe i can find data sheet if you need it....send u2u if u do

If it is 3 wire then it's very likely to be hall effect / proximity. Are the connectors on the back of the dial at all useful?

Often there will be 2 pins for lighting and then either 2 or 3 for the speedo.

[Edited on 19/8/09 by BenB]

quote:

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Originally posted by BenB
If it is 3 wire then it's very likely to be hall effect / proximity. Are the connectors on the back of the dial at all useful?

Often there will be 2 pins for lighting and then either 2 or 3 for the speedo.

[Edited on 19/8/09 by BenB]

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