HALL Switch Endstops LR4

[Sam_Tritto (Sam)]

Ok, I have been going through the topics and I have spoken about using HALL switches in my build threads, so I thought i would start my own discussion so I can keep all the relevant details specific to my build. Also peeps, please let me know if this thread is in the right topic or not. Cheers.

Machine Details:

• Lowrider 4
• plan is to run grblHAL on either, BTT Skr Pro v1.2/BTT Ocotpus V1.1 or Mellow FLY D5 Board (Why? because I have like 2 ro 3 of each of these laying around from building Vorons)
• Makita Spindle

Note: I will update this list as the thread continues to help other work out it this thread suits their needs.

I have gained some info and I will start putting this into practice once the sensors arrive and I can start testing.

So I am going to follow @stevempotter example and make use of @which_carpenter design and have the HALL Switches remain on the endplates/carriages like @vicious1 suggests. If anyone else has suggestions or comments that have already covered these issues please reply.

Limit switch arms

My Hall effect switches work so well, I also added one to the upper Z, for homing the Z axis before I use the touchplate to re-home Z-zero to the material or spoilboard surface. These Hall Effect Switches (AH3391Q; not analog Hall sensors) have the following advanges: Cheap. Much cheaper than inductive sensors. Very reproducible (15 microns repeatability) The chip and magnet are very small so don’t get in the way or hook on things. Won’t ever break due to mechanical wear or metal fatigue. Not…

Possible improvement to LR4 re. homing issue of switch blades keep getting popped off?

I really liked this suggestion. With them being able to run at 5v and using an open drain they’re really easy to use in place of the mechanical switches. I’ve looked at adding inductive sensors but with their higher voltage requirements and the way their signaling works (at least the ones I bought) they would require extra components and got more complicated than they were worth pretty quickly. Anyway I drew up some mounts for SIP-3 hall effect sensors for the y axis, I expect they’d need a 5 …

[Dreyfus]

Following with interest.

[CesarH (cesar)]

You could use the GL-8H sensor. They run with 5v. I have had good results with them in 2 non V1 builds.

My lr4 runs with the stock switches( i just added some 2mm plastic behind the screw so the lever gets triggered always)

[which_carpenter (David C)]

I’ve ordered some switches which will get here this week so I’ll test the print I designed. I’ll also tweak it for the z, and x axes.

If anyone prints them before I do let me know how it goes.

[stevempotter]

@CesarH

You could use the GL-8H sensor.

Those are big and clunky. They can be accidentally triggered by any metal. And they cost much more than Hall sensors.

[stevempotter]

Here is the Hall switch listing at Digikey (US, thanks Doug)

https://www.digikey.com/en/products/detail/diodes-incorporated/AH3391Q-P-B/6575197

There’s plenty of similar products, so feel free to shop around and report back here.

Here is the description of this family of Hall switches:

https://www.digikey.com/en/product-highlight/d/diodes/ah336xq-ah339xq-hall-effect-sensors

[stevempotter]

Here is the detailed spec sheet from the manufacturer.

AH332xQ.pdf

I would probably use AH3321Q, the least sensitive one, and a 5mm rare earth magnet. Use a compass to figure out where its South pole is (its N points to it), and point that at the markings on the Hall Switch.

[CesarH (cesar)]

They could be triggered by metals yes, but they are not big at all: they are: 2cm x 0.6cm x 0.6cm

[Sam_Tritto (Sam)]

Hi Steve, just checking, with the 1K resitor, what does the watt have to be? I got access to 0.5 & 1.0 at the moment. 5 watts I can get also.

[stevempotter]

0.5W is more than enough. 0.25W probably is fine too. I=V/R= 5/1000 or 5mA or 25mW.

[Sam_Tritto (Sam)]

Wonderful, thank you for reply! Appreciate your help

[Dreyfus]

To keep it all clear and in one place for anyone (me) following along do you have a wiring diagram for the switch, cap and resistor?

[Sam_Tritto (Sam)]

Here is a diagram from the Data Sheet

Here is a screenshot from @stevempotter video found https://youtu.be/ztcMPmEYCmw?t=763

[Dreyfus]

Crikey these things are tiny!

[DougJoseph (Doug Joseph (design8studio))]

@which_carpenter

Here’s an image from the datasheet. You can picture poking the 3 prongs into the ground and looking down at the part. The taper points to where the sensor is. So you want the taper pointing to the south side of your magnet.

@which_carpenter thank you, super helpful info. I still have a couple more quick questions…

@which_carpenter

Blockquote 1. do I connect to the two outside leads/wires, isolating the center lead/wire?

Ground should have a capacitor between it and your voltage, and output should have a resistor between it and the voltage.

Please, can someone link for me what capacitor to get and use? I have a supply of resisters, but I don’t think I’ve ever bought a capacitor in my lifetime!

@which_carpenter

Blockquote 1. does it matter which lead/wire gets attached to what? Or do I have to be careful, treating the thing like a “one way only” type device?

Yes you can think of it as a one way device. Output and ground cannot be swapped. The device needs the relationship between vdd and gnd established for the switch to work properly and allow output to be pulled down.

So I run three wires? Single out (to Jackpot board), Voltage in (from Jackpot board), and a ground wire coming away to— to what? And a capacitor connecting ground and voltage? Or so I just “terminate” the outcoming ground lead to the capitor? Sorry to be so green on all this.

[DougJoseph (Doug Joseph (design8studio))]

@stevempotter

Doug,

The place where the switch has numbers etched on it is the sensitive part. You ought to move this discussion over to Tom’s all about Hall switch endstops. There I posted the datasheet.

Thank you! So helpful.

[DougJoseph (Doug Joseph (design8studio))]

Anyone happen to have a link to the “10F - 100NF capacitor” mentioned by Prof. @stevempotter ? to make it easy to source and know I’m getting the correct thing?

Also, although I’ve never needed a capacitor before in my life, is this something I should get a variety pack for it? Until I needed a resister, I had never needed one, but I bought a variety pack and was later glad I had!

[stevempotter]

@DougJoseph

what capacitor to get and use?

I use 0.1 mfd = 100 nF

It is marked 104 which means add four 0s to 10 (in picofarads)

You can get a whole assortment of filter caps for very cheap on Amazon.

[DougJoseph (Doug Joseph (design8studio))]

@stevempotter

I use 0.1 mfd = 100 nF

This assortment look like a half decent deal?

https://www.amazon.com/BOJACK-Capacitor-Multilayer-Monolithic-Assortment/dp/B085RDTCCV/?th=1

I also found this one, which has 650 pieces instead of 300 pieces:

BOJACK 10 Type Values 650Pcs Ceramic Capacitor Assortment Kit Capacitors from...

[Dreyfus]

3 components and a connector in a square form factor with a couple of mounting holes. Candidate for home pcb board milling?