magnetic sensor

Using Arduino Sensors
1

Hello all
i want to buy a magnetic sensor for a parking spot. So i want to sense the car when its there and when its gone. I saw that the hall sensors are very famous for that but i do not know how to choose one. i just want to connect to an arduino get the readings and i guess with a threshold to be able to tell if there is a car there. i think it will be precise enough. also if its buried under the parking spot it will be protected from weather.
so has anyone done that? or knows which magnetic sensor can be used for that ?
thanks

2

The typical Hall sensor you are thinking of is usually used to detect nearby magnets, and wouldn't work for a vehicle. However, a magnetometer (used in electronic compasses) might work, like this one: SparkFun Triple Axis Magnetometer Breakout - HMC5883L - SEN-10530 - SparkFun Electronics

Most commercially available vehicle detectors, like driveway vehicle alarms and traffic light controllers, use buried coils of wire and require sensitive electronics to process the signal.

3

what kind of input does this sensor produce? you seem to know a lot on the topic. how would you do it?

4

bioMaynard:
what kind of input does this sensor produce? you seem to know a lot on the topic. how would you do it?

Did you read the Quick Start Guide and download the sample Arduino code?- they might help

5

In a magnetic compass, the magnetometer allows to detect the direction that the Earth's magnetic field is pointing, by measuring the relative magnetic field strength in three perpendicular directions. Nearby iron-containing objects will distort the direction of the Earth's magnetic field, so if a car is nearby, it will look as if "North" has moved. The magnetometers are very sensitive, so normally people have to go to great pains to avoid or reduce this effect.

I would bet that the Sparkfun magnetometer would easily detect the difference between a vehicle nearby and "no vehicle" but it would probably require some experimentation to arrive at a reliable setup.

6

i see. magnetometer it is then :slight_smile: thank you both for the information !!!