WEBVTT
Kind: captions
Language: en

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Hello.

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Today we're demonstrating linear sensing with
NVE's brand new AET-Series linear position

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and off-axis rotational sensors

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Here's how it works; Linear magnetic scale,
or linear magnetic tape, is a special type

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of magnet that has alternating north and south
poles molded into a thin strip, often backed

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with adhesive

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This arrangement produces a strong magnetic
field on one side of the tape and zero field

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on the other

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The magnetic poles repeat periodically with
a precision tolerance spacing known as the

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"pole pitch."

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NVE's new AET-Series TMR sensors have phase
shifted linear elements.

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When the pole pitch matches the phase shift,
the sensor produces high amplitude sine and

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cosine outputs for position interpolation.

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The AET-Series has several sensors optimized
for many of the most common pole pitches.

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Today we're using the AET500-02E with a five-
millimeter linear magnetic scale.

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Here's the demo board.

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And here's the magnetic tape with Gauss paper
to show the location of the poles.

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The AET500 fits in an eight-pin SOIC, which
is amazing for a five-millimeter scale sensor.

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We're displaying the repeating position along
the tape with a micron resolution display

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controlled by an ATtiny85 microcontroller.

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We have one red and one yellow LED to indicate
pole position. Since this is a precision demonstration,

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we're using an inexpensive dual CMOS op-amp
to boost signals to full scale.

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AET-Series sensors have a high output, so
we only need a gain of three in this circuit

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We'll slide the tape under the mounting fixture,
and turn the power on--and the sensor reads

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the position along the zero to five millimeter
segment to micron precision.

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The meter counts 1 to 5000.

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As we move along the tape, the red LED brightens
proportionally to distance, reaching maximum

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brightness when a pole is detected, and the
yellow LED flashes when the sensor is within

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one human hair of a pole.

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The resolution is simply amazing!

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In this demo, we needed to use our largest
pole pitch sensor for the tape position to

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be reasonably controllable by human touch
at all.

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And when we take our hands off the tape, the
meter keeps a steady reading, showing how

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low noise and high precision these sensors
really are.

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Here's the circuit.

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The sensor has half-bridge sine and cosine
outputs, and we boost them to full scale with

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a noninverting amplifier configuration.

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The microcontroller calculates the position
with an arctangent function and interfaces

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to a seven-segment display via I2C.

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LEDs indicate the pole position

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The firmware is simple.

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We read the sensor and calculate the position
along the five millimeter scale by converting

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the angle to microns.

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We output the position on the display and
the indicator LEDs.

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Key features for NVE's AET-Series Linear Positioning
and Off-Axis Rotational sensors include:

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Low hysteresis and excellent linearity for
high accuracy.

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Robust airgap for mechanical latitude.

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Ultraminiature packages for the most space-constrained
systems.

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And micron precision due to the sensor's low
noise and high sensitivity.

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Design support for AET-Series sensors can
be found on our applications page:

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Click, email, or call for more information,
or to buy NVE sensors today.