Hall Effect Sensors?

[OldTimerNewPilot]

I ran across these "Hall Effect Sensors" and am a little confused. Can these be used in place of potentiometers or are they like switches? If they are like potentiometers, how do you know what "value" to use instead, like 10k, 100k, etc? Magnet strength/distance? If they are switches, why must they use a potentiometer connection? Thank you all for the help.

[AK Mongo]

Yes they can be used in place of any analog sensor(potentiometer). This thread will answer a few of your questions:

http://www.mycockpit.org/forums/showthread.php/21303-Experience-with-the-use-off-Hall-sensors-instead-of-potentio-meters?highlight=hall+sensors

You can get magnetic digital switches that are on/off. Hall's do not do that, they read a proportional signal, just like a pot, but won't ever wear out. There are some limitations to get a near-linear response, but they aren't too bad if forced through a short angle.

Reid

[maussuam]

I am building a Sidestick and will do the position sensing with hall sensors and an arduino board with an ethernet shield. The sensor I want to use is a Melexis MLX90316, which have analog, SPI or PWM output. Datasheet (http://www.melexis.com/Assets/MLX90316-DataSheet-4834.aspx) The programming can be found here: http://interface.khm.de/index.php/lab/experiments/rotary-positionsensor-mlx90316/

Bastian

[Mike.Powell]

I ran across these "Hall Effect Sensors" and am a little confused. Can these be used in place of potentiometers or are they like switches? If they are like potentiometers, how do you know what "value" to use instead, like 10k, 100k, etc? Magnet strength/distance? If they are switches, why must they use a potentiometer connection? Thank you all for the help.

There are several types of Hall effect sensors.

"Rotary Hall effect position sensors" look very much like potentiometers and can be used in some of the same applications. They are expensive, about $40~50, last time I checked. However, it's important to remember that they are not potentiometers and can't be used as drop in substitutes in every case. They do work in many USB game controllers and joysticks, however. See http://cubpilotshangar.net/page30.html for information about using this sort of Hall sensor in a Cougar joystick.

A proportional or linear output Hall effect sensor is a basic magnetic sensor. It looks like a transistor, and is inexpensive (about $1). You can use them as the basis for a DIY flight control. For some thoughts about that, see http://www.mikesflightdeck.com/old_stuff_5.htm Scroll down to the 5 May 2009 entry. Also see http://www.allegromicro.com/en/Products/Part_Numbers/1301/1301.pdf for technical information from the manufacturer.

A digital ouput Hall sensor produces a binary logic output. It's triggered by a magnetic field which is stronger than its design threshold. This type of Hall sensor is effectively a magnetically triggered on-off switch. It's also very cheap.

[maussuam]

I build an airbus-style sidestick at the moment. The position pickup is made by a hall sensor, interfaced with an arduino board with a network shield on it. The sensor is made by Melexis and is called MLX 90316. There are different versions, with SPI-Interface, PWM or analog voltage output. Datasheet (http://www.melexis.com/Sensor-ICs-Hall-effect/Triaxis-Hall-ICs/Rotary-Position-Sensor-IC-566.aspx) There is someone, who made this kind of interfacing already: click (http://interface.khm.de/index.php/lab/experiments/rotary-positionsensor-mlx90316/)
Melexis also offer a 3D Version of this sensor, perhaps this will fit to your project.
The other possibility is to take a linear potentiometer (the expensive one) sensor (http://nz.element14.com/honeywell-s-c/06mtl0025a/transducer-linear-position/dp/7088530?Ntt=708-8530) or a inductive sensor (which can only detect a range of 10mm) inductive sensor (http://nz.element14.com/contrinex-gmbh/dw-ad-509-m18-390/proximity-switch-inductive-analog/dp/4624518?Ntt=462-4518)

Regards from Berlin
Bastian

[Mike.Powell]

Is it possible to get a hall effect sensor hook up to horizontal rod that moves forward and backwards ?

Rhys

Yes. There are companies that make linear position sensors that incorporate Hall sensors. For example: http://www.movingmagnet.com/en/analog-magnetic-field-amplitude-measurement/ There is an illustration of a linear position sensor in the lower left portion of the page. Getting good linearity with minimal hysteresis requires using the proper type of magnetic material.