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Topic: what input pin is it using? (Read 5832 times) previous topic - next topic

Joes

Quote

I think you need to find out for certain what sort of sensor you have and what sort of signal it outputs. Is it definitely a Hall effect sensor? I would have thought that an MVR sensor was more likely.


how can i test to see if it is a mvr sensor?
mite be easier to just get a now one so we no what we have then somthing like this?
http://www.amazon.com/Inductive-Approach-Proximity-Sensor-Detection/dp/B004U4GCCW/ref=pd_sxp_grid_pt_1_0

but would be better in 5v

PeterH


how can i test to see if it is a mvr sensor?


If it's an MVR sensor then the sensor will be slightly magnetic and it will produce a weak alternating electrical signal when ferrous material is moved towards and away from it. The magnitude of the signal is determined by the speed of the movement. This type of sensor is commonly used to detect the position of an iron/steel toothed wheel.

Hall effect sensors are not magnetic but require a magnet in the part being sensed.
I only provide help via the forum - please do not contact me for private consultancy.

Joes

this sensor is very magnetic on the end so might be, is that easy to be used with the arduino or am i better off getting a hall sensor ?

i thought it must be a hall sensor as a lot of the cars had a hall sensor looking at a steel trigger wheel for the engine rpm, so i thought these might be the same but obviously not

PeterH


a lot of the cars had a hall sensor looking at a steel trigger wheel for the engine rpm, so i thought these might be the same


They probably are the same, but those other cars you're thinking of aren't using Hall effect sensors either.

You need to measure the voltage level over the range of speeds you need to support when the sensor is installed. You will almost certainly need to do some signal conditioning to take your variable voltage incoming signal and clean it up to a square wave.
I only provide help via the forum - please do not contact me for private consultancy.

Joes

so i will be easier to put some hall sensor on it like in link then?

GoForSmoke

It could be as simple as a magnet in a coil. When a gear tooth passes close across the axis of the coil it will induce current in the gear tooth (eddy current) and the coil, the latter which can be picked up as a pulse with strength in proportion to the speed of the gear tooth. Such a sensor would not be affected by dirt or wet the way an light and sensor would. Unlike a Hall sensor, it would not require any magnets placed on the turning wheel.

If it is, don't try feeding it directly to Arduino until you know what directions make +V and -V.

Why buy when you already have something that must work or the car won't?
Can you get a part # on the sensor? Maybe it would be in a shop manual for the vehicle.


Nick Gammon on multitasking Arduinos:
1) http://gammon.com.au/blink
2) http://gammon.com.au/serial
3) http://gammon.com.au/interrupts

Joes

ahh yes there is a pos and neg symbol just above the pins on the sensor that would explain why they are there so how do i intergrate that with the arduino?

trying to find out information about it is near enough impossible ans manufacturers keep that information to themselves 

PeterH


so i will be easier to put some hall sensor on it like in link then?


I would have said that an MVR sensor is the best one for the job - that's why they are so commonly used for this. But you need to cope with the fact that the amplitude of the output signal varies with speed, so you need to apply some conditioning before you can pass it to your input pin.
I only provide help via the forum - please do not contact me for private consultancy.

Joes

i just looked on my altodata and that says 60rpm 65 mV ac min
does that mean much to you or any help?

GoForSmoke

We can Google a part number.
Nick Gammon on multitasking Arduinos:
1) http://gammon.com.au/blink
2) http://gammon.com.au/serial
3) http://gammon.com.au/interrupts

GoForSmoke


ahh yes there is a pos and neg symbol just above the pins on the sensor that would explain why they are there so how do i intergrate that with the arduino?

trying to find out information about it is near enough impossible ans manufacturers keep that information to themselves 


That would be in a repair manual even if it's just a company number.

There's a + and a -. Any other pins? The thing could be a package with built-in amplifier for all I know. But 60 rpm 65 mV AC... they wouldn't feed it AC yet + and - pins don't sound AC to me.

How about the make, model and year of the vehicle? There are automotive forums where the answer may be found as well.
Nick Gammon on multitasking Arduinos:
1) http://gammon.com.au/blink
2) http://gammon.com.au/serial
3) http://gammon.com.au/interrupts

Joes

no part numbers on it just have 2 pin's on it. it is only a very little thing so i dont imagine there is much in it. i am extremely tempted to say sod it and just purchase some after market hall sensors as the car is an early 1980's car and everything mechanical in the car is from an 08 plate vehicle so me fitting those sensors is broad as it is long to fit either or, probably easier to fit the after market ones as i havent got to try and find trigger wheels to fit the cv joints and drill out hub carriers to fit them. at least with the hall sensor i can just get it to look at the bolk heads on the inner cv joint.

GoForSmoke

You could try a Hall *switch* (security type, very cheap, very sensitive and reads digital) and a magnet with a toothed or holed steel/iron wheel between the two. Iron between switch and magnet should suck the field in. I'm just not sure how big a hole you'd need for enough field to get through, depending on the thickness of the wheel and how close the sensor and magnet are.

If you put 1 magnet on a shaft then you will get 1 pulse per turn and the rest of the time nothing. With a fast turning shaft it's probably all you need but otherwise maybe not.

Nick Gammon on multitasking Arduinos:
1) http://gammon.com.au/blink
2) http://gammon.com.au/serial
3) http://gammon.com.au/interrupts

Joes

ok thanks i'll have to have a play but now we are back to the original question how can i run 3 hall inputs as i can only have to at mo?

GoForSmoke

If you -have- to use interrupts then 2 of them can be level change interrupts.

I keep trying to get you to get sensors working so you can tell if you -need- to use interrupts at all.
Chances are that you don't. Chances are that you could catch the HIGHs a few times in a row as each magnet/gear tooth passes each sensor. But you won't know until you get sensors working and until you know it's probably not a great idea to design the sketch.


Nick Gammon on multitasking Arduinos:
1) http://gammon.com.au/blink
2) http://gammon.com.au/serial
3) http://gammon.com.au/interrupts

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