Allegro A1301

Using Arduino Sensors
1

Good day everyone,

I am a new face in the world of Arduino (and electronics) and I wanted to try my luck with an Allegro A1301 magnetic sensor.

My goal is to make a device that can be used to sense some metal approaching it.

One of my friends recommended me to buy an Allegro A1301 sensor.

So I did, I wired it and (first pin to 5V, second to GND and third to the pin nr.2.).

Thereafter I wrote a sketch which checks whether there are voltage fluctuations in the sensor (using the digitalread function and then printing the results in the console) when I approach a Neodymium magnet towards it.

My results show me random numbers varying from 412 to 350 which repeat at regular intervals.

I assumed that the differences were determined by me approaching and retracting the Neodymium magnet from the sensor.

In reality, after modifying the sketch and adding an extra variable to read an unused slot, I realized that the results were similar in nature.

Therefore I would like to ask the kind forum members the following questions:

  1. Because I get the same results when I "read" both an empty slot and the slot with the sensor, is it possible that my sensor is broken? If yes, how can I test to find it out?

  2. What kind of magnets is the AllegroA1301 sensible for? Does a magnetic sensor "feel" fluctuations caused by approaching a metal piece to it?

  3. Is there another way to wire the sensor?

  4. Are the results (412-350) voltages or random numbers? Do I have to process the raw data in order to get some better results?

Thank you and have a nice week ahead!

2

Hello
I think you need to go back to the basics
Have you looked at the data sheet for this device?
You say you want to detect "metal" then talk about "magnets"
This device gives an output relative to a magnetic field, so a lump of aluminium isn't going to do much.
What do you mean by "slot"?
The Allegro site suggests that this is an end of life device, so maybe not the best choice.
I think your best bet is to decide what you really want to achieve - metal or magnet, choose a different device like the recommended A1308 replacement.
Allegro are generally pretty good at application notes, so I would start there, before even starting with code.
Just a quick look at the spec suggests that the output is analogue, so digital read may not be much good - I would expect this device to give a voltage output on the output pin, so analogue read would be more appropriate. Hall effect "switching" devices provide a digital output depending on the strength of the magnetic field.
Note that some of these devices need a load (resistor) on the output pin plus decoupling Vcc to GND
They are pretty resistant to abuse (getting it wired up incorrectly), but will only take so much.
Read the data sheet.