♪ It's a Magnet ♪
Hello.
Today we're demonstrating magnetic sensors
for Arduino boards.
We'll look at two types of sensors:
digital magentic switches,
which switch at a particular magnetic field;
and analog sensors, which provide outputs
proportional to the magentic field.
These NVE sensors are precise, very sensitive,
and easy to interface to Arduino boards.
First, let's look at a digital switch.
It's powered with five volts from the Arduino board,
and connected to one of the digital I/O pins.
We soldered the sensor to a prototyping board;
this board is only a quarter-inch across.
The blue LED goes on when the sensor switches.
You can see it can detect a magnet quite far away,
for more tolerant systems.
Here's the program.
There's not much to it, 
but a couple things to point out.
The sensor has an open-collector output,
so we turn on 
the microcontroller's pull-up resistor
by writing a "HIGH" to the input.
And the open-collector output 
goes "LOW," not "HIGH" when it turns on,
indicating a field is present.
We demonstrated an AD004,
which is one of 
NVE's most sensitive sensors,
but we have several switch points available.
Now let's look at an analog sensor,
which provides an output
proportional to the field.
These use Giant Magnetoresistance technology,
so they're inherently sensitive enough that we
don't need a preamplifier.
we're just running 
the differential output 
into two Arduino analog inputs.
And for demonstration, 
we're running an Arduino PWM analog output
into a meter set up 
for 5 volts full-scale.
Here's the sensor soldered onto the board.
We move the magnet around...
and you can see it's really sensitive.
The program is pretty simple.
We subtract the inputs 
to get the differential output...
...and scale it for zero to five volts.
We demonstrated an AAH002, 
but NVE has several versions available.
So there you have it--
magnetic sensors for Arduino boards.
Call, click, or email NVE for more information,
or to buy the sensors, boards or magnets
we demonstrated today.
