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I have a piece of hardware which uses reed switches and neodymium magnets. When I attempt to produce this hardware in batches I find that some reed switches that I have are more sensitive than others and I would like to find an efficient method in selecting reed switches which are not over or under sensitive.

The most obvious method would be to build a rig that has a magnet placed at the correct distance and another to detect over sensitive reed switches.

I am thinking of 3d printing the rig, creating a continuity circuit, and placing contacts that would allow me to place reed switches in place to test.

This method will be quite slow when going through many reed switches, could anybody suggest a more efficient method?

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    \$\begingroup\$ How many switches are you testing and what is your budget? I'm sure you could design a system to test dozens per minute automatically but that would only make sense if you are using hundreds or thousands per day. \$\endgroup\$
    – vir
    Commented Dec 12, 2022 at 23:30
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    \$\begingroup\$ Magnets have large different tolerances inside both Reeds and external. TV's once used adjustable coils due to CRT tolerances to adjust pincushion square the corner deflection, which could be a selection on test of R. and a small booster coil. Or the Reeds could be binned ahead of time and select the closest of xx% of the batch before soldering with an electromagnetic coil where you read current for same distance trip current. Test a bunch and measure hysteresis thresholds. Or solder one end and just height of other end to the same gap from magnet to close switch, then fix the end \$\endgroup\$
    – Tony Stewart EE75
    Commented Dec 13, 2022 at 0:33
  • \$\begingroup\$ @vir I am testing around 300. Would be good to buy something that could perform most of the task and I can then adapt. Thanks for your answer! \$\endgroup\$
    – Jaspal Singh Rathour
    Commented Dec 13, 2022 at 0:45
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    \$\begingroup\$ Adjustable electromagnet could be tuned but take more energy or adjust the magnet height with Mu metal spacers \$\endgroup\$
    – Tony Stewart EE75
    Commented Dec 13, 2022 at 0:50
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    \$\begingroup\$ Make a tube small that you can repeatedly position the reed switch in. Wind a single layer of magnet wire the length of the switch, including leads. Then measure the current at which each switch closes. \$\endgroup\$
    – John Birckhead
    Commented Dec 13, 2022 at 15:16

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