Hall effect Sensors and issues - wiring knowledge and voltages

Hi Guys

I recently decided to have a go at upgrading to Hall effect sensors - due to having issues with the accuracy of standard limit switches. I ended up buying three of these:


However I’m having woes when plugging them in - if I plug in correctly as tested with a 9v battery the Z axis moves in the wrong direction then I get a door open error. If I plug in reverse nothing is sensed. I’ve also tried a combo with the additional wire but no luck. Im suspect these are too high a voltage for the shapeoko as they are 5v. Can anyone confirm or shed some light on it? When connected I cannot get the light to illuminate as hoped. I can when connected to a 9V battery…

I read this thread and it suggests additional voltage is required - and the sensors @Bonch used look to be 3v.

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Check the output voltage of the board when triggered. The controller board has 3.3v on the pins in an idle state. I wouldn’t recommend anything greater than 5VDC on the output of the board connected to the C3D controller inputs.

Output should see a change hi-lo or lo-hi when triggered.

This is where I’m struggling. When I put a multimeter between the pins I get a reading of 5v - when I connect a hall switch in it’s like 1.5.

when I try to trigger the switch nothing happens.

Try breaking the connection from the hall switch board and controller and measure the voltages and change in state.

You should see a definite change in state when triggered.

Some sensors output an analog variable signal from 0-5 VDC, you will want the digital which IS ON OR OFF. Depending if it is hi or lo is how you will need to adjust the GRBL parameters.

I looked at the picture in the original post and in one of the pictures it shows a dark rectangle connecting from the black output wire to the positive or negative depending on the configuration. It also says NPN/NO so based on this I’m thinking you may need an external resistor maybe (the mysterious black rectangle in the picture).

So you may need to try maybe a 10k or higher resistor from positive 5+ to the black wire and when triggered it should pull LOW to ground.

Basically the resistor pulls the black wire to +5 then the switch grounds that side of the resistor to go low.
This is just an assumption because that is what it appears to look like in the pictures and not much information is provided but in my experience with electronics, most likely this is the intended usage.

Something to try, I doubt it would hurt anything either way because the load current according to specs should be 200ma or less.

With a 10k resistor at 5 volts (I=V/R) we are at 5/10000
which is .0005 Amps or .5 Ma

I had a little play with my multimeter. If I connect:

Blue to negative 9v battery
Brown to positive

Black to voltmeter pos
Voltmeter to negative 9v

I get the switch working in principle - the light goes off and the voltmeter shows the black as being switched off.

This suggests the switch is a powered switch that need to be ran from a power source. But I don’t know if thats possible to do on a S3? And or if it would conflict.

I think this is how it needs to be wired - Just not sure on the best way to do it?

I imagine the blue wire should go to the ground wire on the board, the black to the positive on the board then a additonal voltage should go to brown?

@Bonch may be able to lead you in the right direction with this.

You can use an external 5 volt supply, or use a 5 volt pin on the controller if you find it. But either way make sure you ground the external supply with the ground of the controller board.

It’s typical for inductive sensors to require power.

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Not sure how much help I will be but here is the link to what I did on my machine. The break out board is powered by a standard external 5 volt power supply for a cell phone charger if i remember correctly. The hall effect sensors have a power side and a signal side both with a ground. The power side is for the LED lighting and the signal side is triggered by the magnetic field. All six of my sensors are connected through telephone wire and connect through RJ-45 connectors to the breakout board. Then the breakout board is connected to the main Shapeoko 3 controller board. Hope this may help but familiar with the sensors you are using.

My guess is that you wired the sensors in normally open or normally closed mode and need the opposite. The wiring diagram on the link shows they can be wired both ways. I went through that aggravation on an emergency stop switch and it couldn’t be changed because of its design and I to purchase the alternate configuration. You may want to try switching that wiring and go with a 5 volt power supply - they are pretty cheap and see if that might help.

Hope something here helps. I by no means am an electronics wizard and the gentlemen I bought my sensors from helped me get mine all up and running. But then again he designed them for this specific application.

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Thanks guys, I tried a few things last night but no joy - @rogwabbit/@Bonch it will just need a 5v supply to make it run, however there lies the problem unless I can pull it from the board - I don’t have any more plugs available to me in the garage and can’t add any more…

I’m thinking unless I can pull from the board I need to look at moving to reed sensors - not as glamorous but should do the same job…

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A cheap power strip and a 5V usb plug is probably the way to go. Reed switch can work no power needed there, and you can get creative with magnets. You can probably pull power from the SPI header pins in a pinch.

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In just heard back from Carbide support - they have pointed out a 5v supply on the board I could tap into with my soldiering iron…

decisions decisions…

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