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Hall Effect Sensor Normally Closed to Normally Open

Madaxe

Aug 21, 2023
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I have these little Hall Effect Sensors VCC is +5volts and Output is +5Volts Normally Closed State until a Magnet is passed by the sensor and then the Output Drops to 0V / Open Circuit.

My CNC machine requires a switch that is Normally Open, until the limit switch closes and send 5v tot he controller.

I need some help creating a simple circuit that will invert this state.

I believe i need an Inverting Amplifier circuit, if this is correct I have no idea how i would build one or what the resistor values would be.

Can anybody help

Thanks

Marc

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Harald Kapp

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Can somebody show me a bread board diagram of the best solution?
Define "best"?

Here's a simple solution:
1700461700302.png
When in = 5 V, out = 0 V.
When in = 0 V, out = 5 V

But, there's a potential catch: When curent is drawn from "out" while out = 5 V, this current will pass through resistor R1 and thus a voltage will drop across R1. Consequently the voltage on "out" will drop below 5 V.
Since we don't know the current your CNC machine draws from out, we can't account for this effect.

Another option, as pointed out by @danadak , is the use of an active inverter, e.g. a NLV18HC1G04-D:
1700462018808.png
I have these little Hall Effect Sensors
Make and model? There may be other options.
 

danadak

Feb 19, 2021
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The SN74AHC1G14 should suffice, just the part no other passives needed other that a bypass cap
across its VCC and ground pins, say a 4.7 uF 10V tantalum :


1700479891449.png


1700480717963.png

Note the transistor circuit, with 2 Rs and a cap, more parts but easier to build a
perf board prototype than the above, your call poster.


Regards, Dana.
 
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Madaxe

Aug 21, 2023
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That's awsome, best i would define as something a Mechanical Engineer, like me could follow as long as i can drop it on a bread board plug some little wirethings in and it works i will be happy, so i think you guys are awsome and its a black magic to me.
 

Madaxe

Aug 21, 2023
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I'm in the US. I found this guy does it still need a bypass cap to smooth the output signal? Thanks Marc
 

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danadak

Feb 19, 2021
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I'm in the US. I found this guy does it still need a bypass cap to smooth the output signal? Thanks Marc
Bypass cap is used to insure clean logic level out and to remove noise at supply pin
that would glitch the output.


Regards, Dana.
 

Madaxe

Aug 21, 2023
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I'm using EasyEDA this is what I have so far based on your recommendations. With 8 x RJ9 connections to my Hall Affect Sensors and the ability to tie two outputs together.

I still have to add a power supply i have 24volts, so any ideas there would be great.

I'm also looking for any recommendations

Thanks

Marc

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Madaxe

Aug 21, 2023
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I found this circuit, i implemented into my board. I think its correct but I'm really not sure can anybody review it for me?

Thanks

Marc

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Madaxe

Aug 21, 2023
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i changed to surface mounted components for the buck converter, is there a free software i can test the circuit in?

can anybody review this for me?
thanks
Marc
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Bluejets

Oct 5, 2014
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You could save a lot of bother if you tossed your existing hall sensors and used maybe a n/c reed switch.
There is also the option of using a standard hall effect module such as a KY-003 which has open collector output and pulls low under a magnet.
Seems to me you are over thinking the application.
 

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Madaxe

Aug 21, 2023
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I have already built my own sensors and now i need to build the controller board, im already into it so what's a little more plus im learning from great people like you.

Plus this might help somebody else.

I added some 5volt take offs for other things, and thickened the tracks where i thought i would have to based on the current / voltages.

I'm still looking for some software to test before i order any thoughts?

Thanks

Marc
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Bluejets

Oct 5, 2014
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I have already built my own sensors and now i need to build the controller board, im already into it so what's a little more plus im learning from great people like you.

Plus this might help somebody else.
There is a lot to be said for the kiss phrase.
Keep It Simple Stupid.( latter not my words mind you but the rest always applies).
 

Madaxe

Aug 21, 2023
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Thanks for the great positive, my board works great, and does exactly what I wanted. I want to add some addition features and capacity so I'm working on the next generation.

I think this is what i need, can anybody help

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Madaxe
 

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Bluejets

Oct 5, 2014
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No idea what your mosfet diagram is supposed to represent in the real world.
As drawn it's simply a dead short.
 
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