Alternate to a Reed Switch

[gramo]

I'm looking for a device that is similar to a reed switch, but with no moving parts.

I'm sure I've read something about a similar device that uses a permanent magnet and a coil type device, and the voltage induced into the coil indicates a passing motion of the magnet near by..

It’s for use with a speedometer, and would like to use something that will have a longer life span than a standard reed switch.

Any ideas?

 

[Nigel Goodwin]

Yes, you can use a coil to detect a moving magnet, just amplify the pulses from it. You can also use a semi-conductor version, a hall effect sensor, you can find these in DC brushless motors (VCR's, dusk drives etc.).

 

[Sceadwian]

They make amplified Hall Effect sensors that are exactly what you're looking for. The sensing distance is going to be as good or better than with the reed part, though more sensative as well.

 

[gramo]

Thanks guys, just the thing I'm looking for