Hall sensors LJ12A3-4-Z/BX

[Mapo]

I ask for help on using the hall sensors.
I purchased magnetic sensors model LJ12A3-4-Z/BX, in the characteristics the maximum frequency is 150Hz but, trying to monitor the speed of a motor, beyond 14Hz the impulse no longer comes out when the magnet passes.
The magnet is neomide, even increasing the strength I don't get great improvements.
What can I do?

[RGV250]

Hi,
They are not hall sensors, they are inductive. All the ones I have dealt with the range is based on mild steel and will have a de-rating factor for other material such as aluminium.



Regards,
Bob

[John Drew]

I use the as5045 from Austria Systems. Although I'm using them for antenna positions they do have a very fast response time and they are Hall Effect. Check the datasheet.
John

Ps I may have given you a wrong lead. The as5045 is rotary not to detect a passing magnet

[Maxi]

I ask for help on using the hall sensors.
I purchased magnetic sensors model LJ12A3-4-Z/BX, in the characteristics the maximum frequency is 150Hz but, trying to monitor the speed of a motor, beyond 14Hz the impulse no longer comes out when the magnet passes.
The magnet is neomide, even increasing the strength I don't get great improvements.
What can I do?

its maybe open collector output. Try a pullup resistor

[shantanu@india]

The datasheet doesn't mention 150Hz... these are cheap sensors on which one cannot rely.
For inductive proximity switch you don't need a magnet but only a ferromagnetic target within 5mm(distance depends on the datasheet)
For better results use Omron. I use omron retro reflective type.

[Mapo]

Thanks to everyone for the advice
I realized this time too, that "the more you spend, the less you spend"   

[top204]

There are a few ways to easily measure rotations with a single Hall Sensor. And the types I have uses are listed below:

1. Use a single magnet and a standard Hall Sensor device. The sensor will pulse everytime the magnet goes over the Hall Sensor. Note that most Hall Sensors require a pull-up resistor on their output line. Also, if measuring low frequencies, place a 47nF to 100nF on the sensor's output line to Gnd. This helps to eliminate stray pulses, and noise. Also, make sure the magnet has a far enough travel to keep its Gauss away from the Hall sensor when it is not to be detected, otherwise the Hall sensor will give random pulses or not pulse at all.

2. Use a Bi-Polar Hall Sensor (sometimes called a Latched Hall sensor). These will give an output state for a change in magnetic polarity only. They will not detect a magnet if it is just held over it, but as soon as the magnet is swiped over it and it sees a change in south/north or north/south, its output will go high or low, and the next swipe will make the output reverse.

The Bi-Polar sensors are used at the end of motors with the circular multi-pole magnet on them, and a microcontroller's Timer peripheral can easily be used to count many thousands of revolutions per minute from them, or just a few revolutions per minute. They can also be used with a single magnet, as long as the magnet is orientated with its poles in parallel to the Hall sensor. I've used these types a few times and the Hall Sensors I used were "SS40AF" and "SS461R".

[Mapo]

Updates,
now I use an iron with a thickness of 3mm and a width of 20mm.
The passage is read well at frequencies up to 90Hz.
I raised the power supply from 8v to 12v for a more defined pulse.
Thank all