Magnetometer sensor


#1

Can somebody suggest a good magnetometer to be used with xenon. This application is for parking sensor.


#2

@abhishek2101, what do you mean by “magnetometer”. Do you mean a magnetic field sensor? How are you planning to use it as a parking sensor?


#3

any help.


#4

when the car parks over the sensor it will change the field which can be detected. this is turns help us know whether the bay is occupied or not.


#5

@abhishek2101, a quick google search led me to these:

https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2380057.m570.l1313.TR2.TRC0.A0.H0.Xloop+detector.TRS0&_nkw=loop+detector&_sacat=0


#6

The MHC5883 was the defacto reference magnetometer in the drone industry. It was then superseded by the MHC5983. Both were excellent magnetometers, the best in the business at that price point. However, both are now EOL’ed by Honeywell. I’ve heard there’s another company which has started production of an equivalent part, but I don’t know if they managed to keep the quality up.

However, for your purposes, you’re probably not concerned about the best, probably just the cheapest. In that case, there are Invensense (now owned by TDK), STM, and many others available. You might check Sparkfun, https://www.sparkfun.com/search/results?term=magnetometer, to see what’s out there and currently shipping.

P.S. Yup, a magnetometer will work great for detecting a car’s presence. An inductive field on a wire loop would be cheaper to mass produce, but if you’re looking to minimize time-to-market, or only need a unit or two, this is a great way to do it.


#7

Depending upon the environment - outdoor or under cover car parking? If under cover parking then commercial systems I have looked at use ultrasound range finder generally looking down on the vehicle at an angle off vertical. You can very cheaply create a sensor yourself using something like an HC-SR05 or indeed for an outdoor solution an in-bumper/fender car parking sensor (when the transmitter and receiver are in a waterproof case) might also work for you but not pointing upward! I have used the parking sensors in lockers to detect if they have anything in them. Unless there is just a piece of paper they are very reliable/accurate because the measurement is pretty accurate.


#8

Using ultrasonic sounds like a great way to get into heuristic hell. Active sensors tend to step on each other’s toes, and I can imagine in a big parking garage made of concrete, there will be a lot of edge cases which will need to be rediscovered.

Not saying people are wrong to have used ultrasound, just that the human time cost is high. Any project is going to have to weigh the pros and cons of available sensors before diving down any one path. From a BOM perspective, using a magnetometer is likely not the most cost-effective way to do a large garage, but it might well be the most foolproof and fastest way to an MVP.


#9

All,

I too am looking for a magnetometer for much the same purpose. Ideally, it would have the following:

  • i2c interface
  • interrupt flag
  • low power
  • Good Particle library support

Any ideas?

Thanks, Chip


#10

Still waiting for inputs from the community.


#11

In the automatic gate industry we use inductive loops, they can be cut into, or placed in a parking spot, a loop detector will sense the change in the magnetic field and fire a relay that you can then use to trigger your photon.