♪ Turn, turn, turn ♪
[Heartbeat]
♪ First gear--it's all right ♪
Hi, I'm Jim Berglund with NVE Corporation,
and I have a simple demonstration of NVE's unique "AKL" digital gear-tooth sensors.
You can buy these on our Website.
Here's the sensor.
We have a ceramic biasing magnet,
and a circuit board with an LED and driver.
As I turn the gear, the LED goes on and off.
Because these sensors are so sensitive, we can go to a fairly wide airgap,
even though this is a small magnet, and a narrow top-land spur gear
rather than a flat-tooth timing gear.
Here's how it works:
A biasing magnet provides magnetic field.
As the gear turns,
the magnetic flux lines are deflected into the direction of sensitivity
by passing steel gear teeth. The sensor produces a digital output
with one cycle per tooth.
a three-wire output or LED driver.
The AKL has a 4-to-8 milliamp output.
When the current is 4 milliamps,
the voltage across this 100 ohm resistor is 400 millivolts, which is
not enough to turn on the transistor. With 8 milliamps, the transistor turns on.
AKL-Series sensors include: a GMR bridge,
consisting of two GMR sensor elements;
a voltage regulator
to allow a wide supply voltage range; a factory-programmable EEPROM
for calibration;
and an output current driver.
AKL-Series sensors have two sensor elements with various spacings.
These are the popular models: The best sensor depends on
the geometry of the gear and the sensor system.
As a starting point, the sensor element spacing can be
one-fourth the gear pitch.
This gear pitch is approximately 2.5 millimeters, so we're using a 500-micron sensor.
So to sum up, we've shown how NVE AKL Sensors
are a simple, flexible, solution for gear-tooth sensing.
Click, e-mail, or call us for more information, or to order parts or demonstration kits.