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Melexis 90217 Hall Effect Sensor — Parallax Forums

Melexis 90217 Hall Effect Sensor

chozin1chozin1 Posts: 2
edited 2006-04-19 05:52 in Learn with BlocklyProp
-Hello All

I'm interested in using a hall effects sensor to measure rpms of an alternator. I used all of the download software from parallax and I assembled the circuit·but I can't get it to work. I've measured the output of·the sensor with > 1K/s rotations and·a basic·stamp2. The output is 0. The·sensor is mounted with the etched side facing the rotating alternator and·a·small magnet is mouted behind·the Melexis 90217·sensor to cause the Hall Effect.

-"...All I desire is knowledge; nothing more, nothing less..."

-CE


Post Edited By Moderator (Chris Savage (Parallax)) : 4/18/2006 5:19:30 PM GMT

Comments

  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2006-04-18 17:19
    You have the magnet mounted in a fixed position?· It sounds like you're saying the magnet is still and you're expecting magnetic pickup from the alternator.

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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • chozin1chozin1 Posts: 2
    edited 2006-04-19 03:19
    Yes, I saw a setup where the sensor is mounted adjacent to the alternator while facing the grooves of the wheel. The magnet isplaced directly on the rear of the sensor. The sensor is "activated" every time a tooth of the wheel passes by.
  • Bruce BatesBruce Bates Posts: 3,045
    edited 2006-04-19 04:28
    chozin1 -

    Slowly but surely, we're getting there, inch by inch.

    Now we realize you're using a gear tooth Hall Effect sensor IC. Now the question is what tooth on what gear? Most alternators I've seen have pulleys and belts, and no gears with teeth.

    Regards,

    Bruce Bates

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  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2006-04-19 05:52
    You are referring to the datasheet.· First of all in that design the magnet is on the back side of the sensor and the magnet is facing the gear, not the other side of the sensor.·· Where are the magnetic teeth in your setup and in relation to the sensor?· Also, the magnet we carry is most likely too powerful to use for a bias magnet.

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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
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