Magnetic sensor/switch

Other Hardware Sensors
1

Hi there
Is there any magnetic sensor or switch that has one time action?
Reed switches stays connected....I need something like when a magnet is near to give an impulse only.
Thanks

2

A coil will produce a voltage, but only in response to a moving magnet. You need lots of turns, and a good place to get such a coil is from a small digital/analog clock stepping motor (the clock will have a second hand that ticks).

Make sure you get the polarity right, the sign of the voltage pulse depends on which magnet pole is closest to the coil and the direction it is moving. The maximum voltage depends on how strong the magnet is and how far away it is and how fast it is moving.

3

I need something like when a magnetic field is present near that sensor, the sensor sends an impulse....if you take the magnet away and go back to that sensor to have that impulse back and so on...like on/off impulse when the magnet is around. But not to close the circuit when the magnet remains next to the sensor (Reed switch like).
Thanks for your fast reply

4

You are welcome.

5

LiquidSoap:
I need something like when a magnet is near to give an impulse only.

Can you elaborate on why an impulse is needed?

6

If I will elaborate won't help you. I just need an impulse...like touch and release.

7

Digital hall sensors work the way you describe.
They switch their output from high to low (or the other way) when a magnet is near.
If you want a shorter 'pulse', then Google "differentiator".
Or use an Arduino to change the magnet detector into a clean/defined 'pulse'.
Leo..

8

LiquidSoap:
If I will elaborate won't help you. I just need an impulse...like touch and release.

You obviously never heard of the xy problem.
I wouldn't be surprised if this is one of such cases.

That said, you can have a reed switch output a pulse by adding a simple RC circuit to it. Do add a diode to get rid of the negative peak.

9

I will explain why I need just an impulse instead of a switch....
In this project is included an Mp3 trigger each trigger plays one track and use a reed sensor that is activated by a magnet....works fine but the problem is when the magnet stays next to the reed sensor it makes a repeat effect. This is why I need an impulse :))
Thank you all

BTW
I like The XY Problem ;D ;D ;D ;D ;D

10

LiquidSoap:
I will explain why I need just an impulse instead of a switch....
In this project is included an Mp3 trigger each trigger plays one track and use a reed sensor that is activated by a magnet....works fine but the problem is when the magnet stays next to the reed sensor it makes a repeat effect. This is why I need an impulse :))
Thank you all

BTW
I like The XY Problem ;D ;D ;D ;D ;D

The actually it is a software problem. Your program should be able to detect an initial level and a continuing level and adjust for each.

Paul

11

It is a cheap China Mp3 trigger....

12

LiquidSoap:
It is a cheap China Mp3 trigger....

Not really an Arduino problem, is it?

Paul