[Ernie34]

I think you hit the nail on the head man. That is a very simple and easy design. I will be milling this on a drill press, Yea I know it not a very precise way of doing things but it will work. I am ordering the hall effect sensors now! Have you thought of milling it out of aluminum and mixing air into the epoxy, That way the epoxy would give a nice glow. Of course you wouldnt mill the hole for the LED, The epoxy would hold it in.

[RomanLini]

That's a good idea, I'm sure some people would prefer a solid aluminium mount.

You could make the LED shine out the top side of the pocket (like I think you are suggesting) but normally the magnet would be over that side when the LED activates, and the magnet may also be attached to a side plate of the machine etc so in some cases that might not be the best location. That all depends on how you position the sensor and magnet on the machine of course.

If you put the LED in the same location as my diagram you could poke it out the end of the aluminium mount and just seal it, the wires have to be sealed anayway so sealing the LED too is no big deal.

[Ernie34]

Looks like I need to go get some scrap aluminum to play with!

[Jesse B]

Those look great Roman. There's an infinite amount of modifications that could be done to suit people's needs, but this seems to be the perfect base platform to go off of. I'm definitely going to incorporate these into my machine one I get it built.

[Ernie34]

Hall effect sensors are on backorder at Mouser. Trying Digikey now. grrrrr

[Ernie34]

Digikey has them instock. Ordered 10 sensors, 100 resistors and the order came to 16 bucks. Not to shabby. Ill post pics when built.

[eloid]

looks good ,

but I had a thought .... "how is the sensitive" of the hall sensor for distance.

would it not be more ideal to have sensor placed (in the middle of the case but closer to the edge?) rather to the far side... the led can stay in orginal place.... this way the switch could be used in vertical postion or horizontal postion. Thus the switch can be mounted in tigher spaces or use the mount holes more effectivly for ajustment if needed... ie z axis you may not have the physical width on the carrage to place the sensor along the width. ( also this way you dont lose .5 inch of travel due to placement of hall sensor in the case)
I can see how a pcb can make the placement of circuit easyer.... pcb would have a nice press fit for casting pocket and would be snap to center... just dont have the time to draw it up... to many projects on the go right now...

[epineh]

Maybe someone who uses the popular CAD program (I don't even know which CAD program is most popular here!) can whip up a CAD design.

Consider it whipped

The drawing is what I would call the plan elevation, should be enough to make most of the part, you will have to work out the 3mm hole for yourself. I saved it as an AutoCAD 2000 binary DXF, should work with most CAM software, your mileage may vary.

I used ProgeCAD btw, free for private use

Russell.

[epineh]

Oh yeah, holes are 4mm wide with 2mm radius on all corners, hope this is OK, I think Roman's version has 1.5mm radius on all corners, only noticed this after I finished...

Russell.

[Jayson]

Hi Roman,

well done on a very good tutorial that is easy for anyone to follow.
Many years ago I made sensors almost the same...

Firstly I drew up my sensor in CAD and machined it into a block of acrylic



Pored in RED RTV silicone



Then boxed it up and pored white RTV over that to make a mold the same as I had machined.



Routed out some PCB's on my first cnc router



Attached the components to the PCB and then put epoxy (with a little black paint) into the white mold along with the PCB.



Your method would have saved about 2 weeks of work...
Once again well done and thanks for sharing for everyone to benefit.

Jayson.

[RomanLini]

Ernie34- Cool! I look forward to seeing your results.

Jesse B- Please do! The more the merrier.

Eloid- My design really needs the magnet over the top surface of the sensor. But you are right it could be constructed so that the magnet is on another side. That would depend on how someone's machine is constructed (which JesseB mentioned earlier).

Normally the sensor would not reduce travel because the magnet can continue past the sensor, which is one of the benefits of this type of sensor compared to many mechanical switches.

Epineh- Thanks so much for doing the .DXF! That is a nice asset in the thread that I'm sure a lot of people can benefit from in the future. I'll look out for the free ProgeCAD in my travels.

I'm sure the 2mm corner radius will be fine, it's probably a cleaner result than the 1.5mm radius I used (which was simply to match a 1/8" cutting tool). I can't see any down side to switching to 2mm.

Jayson- That's really cool, looks like quite a professional way of making sensors! Please post more info if you like, including sensor type and a schematic or just a simple wiring diagram. Eloid already said he preferred a PCB solution, so there's probably other people who would like to see more info on your system as that might be their preferred way of doing it too.

If I was to visually "hack" your PCB it looks like the 3 pin SS441 sensor in the very middle of the PCB mounted face down, with a LED on the end in the bump and a resistor to the LED. What's the 2.5mm spaced part after the resistor? Is that just a solder jumper to select the LED option?

[Ernie34]

Ordered 10 sensors 100 resistors, I already have LED's. I also had another idea but I will keep that one quiet until I see if this works. I got some aluminum last night to start playing. I need to find a milling bit now. Any suggestions? The machining part of this is still pretty new to me. I will be using a xy vise and milling manually. Should be interesting!!!


Ernie

[Ernie34]

So where does everyone get their milling bits at? I need to order some stuff now too!


Ernie

[xspyke]

Thanks for the great idea. Here is my version out of aluminum.

Now I just have to wait for the digikey shipment to arrive.

Sorry for the crappy photo, is from my cell phone.

[Ernie34]

That is VERY similar to what I was going to do. Looks very good. Im looking for places online right now to buy endmills.


Ernie

[eloid]

Thanks for the great idea. Here is my version out of aluminum.

Now I just have to wait for the digikey shipment to arrive.

Sorry for the crappy photo, is from my cell phone.

i would have made the pocket from the back side.... when the electronics are installed and encpsulated you would not see plastic materal except a small
drill hole for led or sloted bar on front or side what ever your flavour.

i would also try to keep the foot print of sensor standard to traditonal micro switch ( with same location for mounting holes) like below
just in case you need to replace on in a snag.... or some else want to replace theres with this open source design .

I also seen a nice tiny 1.5 mm dc jackpower ... was super tight snap fit ... the bugger wasnt to remove... and was tiny( seen at my local electronic store)... I may go that route for my wiring connetions... on my pcb design. easy to replace.... if you have a spare on hand.. I think there would enought room
to fit it all... in that package, if you used smt devices

[xspyke]

i would have made the pocket from the back side.... when the electronics are installed and encpsulated you would not see plastic materal except a small
drill hole for led or sloted bar on front or side what ever your flavour.

i would also try to keep the foot print of sensor standard to traditonal micro switch ( with same location for mounting holes) like below
just in case you need to replace on in a snag.... or some else want to replace theres with this open source design .

I also seen a nice tiny 1.5 mm dc jackpower ... was super tight snap fit ... the bugger wasnt to remove... and was tiny( seen at my local electronic store)... I may go that route for my wiring connetions... on my pcb design. easy to replace.... if you have a spare on hand.. I think there would enought room
to fit it all... in that package, if you used smt devices

yeah, you make some very valid points. I look at these as disposable items. Once the epoxy sets you are not going to service any components in there. That's why I've made 10 pieces and ordered 15 sensors. If I need more in the future, I just open the cut file and cut another 10. Remember we have the machine to make this kind of stuff.

[RomanLini]

Thanks for the great idea. Here is my version out of aluminum.

Now I just have to wait for the digikey shipment to arrive.

Sorry for the crappy photo, is from my cell phone.

Very cool! That's good to see.

It probably goes without saying but I'll say it anyway; with a metal body you need to make sure none of the exposed internal wiring touches the metal.

As long at it is secured properly (so nothing can touch and short out) until the epoxy sets it should work fine.

I have a couple of ideas for "drill press" mount versions that might not be as neat, but can be made with just a drill press and a vice. I'll try and get some time today or tomorrow and make up some drawings.

Ernie34- If you are really going to try milling on a drill press with a XY table you might want to start with plastic. Milling metal like that will usually pull the morse taper out of the drill press, it makes a nasty mess.

Eloid- I avoided putting the pocket on the back beacuse that means the job needs to be turned over to cut the pocket, so they need 2 lots of machining to have botht he pocket and the front step. You are right that it would be a nicer result with the pocket on the back.

[eloid]

Very cool! That's good to see.

It probably goes without saying but I'll say it anyway; with a metal body you need to make sure none of the exposed internal wiring touches the metal.

As long at it is secured properly (so nothing can touch and short out) until the epoxy sets it should work fine.

I have a couple of ideas for "drill press" mount versions that might not be as neat, but can be made with just a drill press and a vice. I'll try and get some time today or tomorrow and make up some drawings.

Ernie34- If you are really going to try milling on a drill press with a XY table you might want to start with plastic. Milling metal like that will usually pull the morse taper out of the drill press, it makes a nasty mess.

Eloid- I avoided putting the pocket on the back beacuse that means the job needs to be turned over to cut the pocket, so they need 2 lots of machining to have botht he pocket and the front step. You are right that it would be a nicer result with the pocket on the back.

-RomanLini -actual you dont need 2 pass to machine the switch body, just a refinment of the design on the aluminum body. If you look closly at my
standard micro limit sw. you see the screw are integrated into the body of the housing, there not a teared flang as the orginal design is shown...
this makes machine a breaze one side only,,, the encapselaten materal is hidden and mount holes would be universal to stand limit switch allowing other users with standard switch to upgrade. Buy remove old switch and poping in the new type no drilling hole require no threading. Due to conforming to the standard footprint still applys to micro limit switchs.

[Ernie34]

Thanks for the great idea. Here is my version out of aluminum.

Now I just have to wait for the digikey shipment to arrive.

Sorry for the crappy photo, is from my cell phone.

I was thinking, Since you have a nice enclosure built, I would either hot glue or a little dab of epoxy to hold the sensor in place and then cut a 1/16in cover for the top. 2 little screws on opposite corners to hold it together and RTV to seal it. That way you could reuse the aluminum enclosures. Orrrr. use a thin acrylic cover that is scuffed on the inside so that the light from the led illuminates the whole cover..


Ernie