[15mgtar]

Guys can I use allergo 3144?

[CarveOne]

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

I suggest painting one side of the acrylic flat black and then engrave a logo into that side of the acrylic. Put that side down and then ya got something cool when it lights up ....

CarveOne

[eloid]

I suggest painting one side of the acrylic flat black and then engrave a logo into that side of the acrylic. Put that side down and then ya got something cool when it lights up ....

CarveOne

like "ESTOP"... but I would do that in aluminum and place plastic lens in the pocket or flood electronics with plastic ecapsulant.... and when dry just give
a finsh cut pass and buff.

[RomanLini]

Guys can I use allergo 3144?

It looks like a very similar device. Here is some data from the datasheet;

3141 THRU 3144

SENSITIVE HALL-EFFECT SWITCHES FOR HIGH-TEMPERATURE OPERATION
These Hall-effect switches are monolithic integrated circuits with tighter magnetic specifications, designed to operate continuously over extended temperatures to +150°C, and are more stable with both temperature and supply voltage changes. The unipolar switching characteristic makes these devices ideal for use with a simple bar or rod magnet. The four basic devices (3141, 3142, 3143, and 3144) are identical except for magnetic switch points. Each device includes a voltage regulator for operation with supply voltages of 4.5 to 24 volts, reverse battery protection diode, quadratic Hall-voltage generator, temperature compensation circuitry, smallsignal amplifier, Schmitt trigger, and an open-collector output to sink up to 25 mA. With suitable output pull up, they can be used with bipolar or CMOS logic circuits. The A3141– and A3142– are improved replacements for the UGN/UGS3140–; the A3144– is the improved replacement for the UGN/UGS3120–. The first character of the part number suffix determines the device operating temperature range. Suffix ‘E–’ is for the automotive and industrial temperature range of -40°C to +85°C. Suffix ‘L–’ is for the automotive and military temperature range of -40°C to +150°C. Three package styles provide a magnetically optimized package for most applications. Suffix ‘–LT’ is a miniature SOT89/TO-243AA transistor package for surface-mount applications; suffix ‘–UA’ is a three-lead ultra-mini-SIP.

The link to the datasheet;
Allegro datasheet for A3141, A3142, A3143, and A3144

I haven't used this device so I can't say much more than that, although it does look like it would work very similar to the SS441 device.

[RomanLini]

I suggest painting one side of the acrylic flat black and then engrave a logo into that side of the acrylic. Put that side down and then ya got something cool when it lights up ....

CarveOne

"Stop! Stop! STOP!!! Arrrrrggggg!"

Hmm, that engraving might not fit.

[Jesse B]

"Stop! Stop! STOP!!! Arrrrrggggg!"

Hmm, that engraving might not fit.

That'd be so great

[flyinwilly]

Do you think it would be possible to use one of these devices to measure the magnetic field induced in the material being cut by the torch to make a inexpensive torch height control ?

I don't know if the field would be consistent enough but it would be interesting to try.

Willy

[Ernie34]

Well,
I decided to use acrylic for 2 purposes.

1. easier and safer for me to mill
2. A HELL OF A LOT CHEAPER!


This is 1 of three as of now.



Ernie

[Ernie34]

yes, that was done on a drill press. he he



Ernie

[CarveOne]

yes, that was done on a drill press. he he



Ernie

I have a weird feeling that you're going to put a 3 axis CNC conversion that drill press before long.

CarveOne

[compfranon]

Some excellent detail in this thread, i'm not ready yet to really think about installing these, but I can certainly see the usefullness. My build is underway.

On hunting through the various UK suppliers the closest I can source are SS443A, with my limited (none) electronic knowledge, it would appear that the difference between your spec and this one is the temperature range,

I'd welcome your nod of approval on this one, as it's a subscribed thread for me, just waiting for the opportunity.

Great thread, thanks for sharing it.

[RomanLini]

Well,
I decided to use acrylic for 2 purposes.
1. easier and safer for me to mill
2. A HELL OF A LOT CHEAPER!

This is 1 of three as of now.

Ernie

Nicely done Ernie!

Looks like you pocketed from the rear? So I'm assuming the hall sensor is at the bottom.

Anyway it looks like it is triggering ok, that's got to be 1/2" or more from the magnet to the sensor.

[RomanLini]

Flyinwilly- About the torch cutting idea, i have no idea if it would work but I doubt it. These sensors need quite a strong magnetic field to operate. One of my first tests was to put the sensor all round an operating stepper motor, there was no effect I could see, the stepper motor didn't trigger the sensor nor did it seem to have any obvious effect on the trigger distance from a proper magnet. So I really doubt these sensors will do what you need.

Compfranon- The Honeywell SS443 is in the same datasheet (see page 1 of this thread). Checking in the datasheet the SS441 and SS443 seem identical but the SS441 needs 115 gauss to trigger and the SS443 needs a bit stronger magnetic field at 180 gauss.

My low power magnet triggers the SS441 from about 5mm, so with a SS443 you might need a stronger magnet, (or get closer) that would probably be the only down side.

If anything the SS443 would probably be a little more accurate because the magnet needs to be closer, and it would have a higher rejection of other magnetic fields (like nearby stepper motors).

I chose the SS441 because it seemed to be more commonly available.

[compfranon]

Compfranon- The Honeywell SS443 is in the same datasheet (see page 1 of this thread). Checking in the datasheet the SS441 and SS443 seem identical but the SS441 needs 115 gauss to trigger and the SS443 needs a bit stronger magnetic field at 180 gauss.

My low power magnet triggers the SS441 from about 5mm, so with a SS443 you might need a stronger magnet, (or get closer) that would probably be the only down side.

If anything the SS443 would probably be a little more accurate because the magnet needs to be closer, and it would have a higher rejection of other magnetic fields (like nearby stepper motors).

I chose the SS441 because it seemed to be more commonly available.

Ah, I know nothing about gauss either appreciate the informative response, looks like a certain one for me then when I get the machine up and running. :cheers:

[compfranon]

Based on 1/2" distance from magnet to sensor, is there a recommended magnet dia that should be used, I thought of these :

http://cgi.ebay.co.uk/100-N52-Strong...item5ad34f784a

[Ernie34]

Thanks!

I am going to build 2 more that are smaller. That was a test piece. I milled from the back and then filled the area with clear silicone. I think it came out pretty good. I still need to get some magnets that are lower power than the one pictured above.


Ernie

[Ernie34]

The only thing that I saw is on the meter the out will not trigger unless being tied to the +...


Is that correct?

[RomanLini]

Compfranon- Well at 100 magnets for 5 pounds you could always give them a shot and find out.

They are Nd magnets, ie rare earth very high strength so they would not be my first choice. But, they are very small, so they might be workable at the right distance. At least because of the small size they would be very easy to work with, just drill a tiny hole in something and a spot of glue holds the magnet in.

If you use a weaker magnet and put it closer you get better accuracy. You can get weaker magnets cheap anywhere, like those plastic fridge magnets in the supermarket. Most have a round button magnet about 10mm diameter that is ideal, look for the older style black ferrite type magnet not a shiny nickel coloured one.


Ernie34- Yes the output needs a pullup resistor. I showed that in the wiring diagrams etc on page 1 of the thread.

A resistor of about 2200 ohms (2k2 or 2.2k) is about right.

If you want LED and pullup resistor, these values below should be good;

[quadtech]

For anyone in India following this thread, Rhydolabz has
the MH183 unipolar hall effect sensor for a decent price.

It appears to be similar to the Honeywell SS441 and has the same pinout too.

http://www.rhydolabz.com/index.php?m...roducts_id=391

Datasheet (available on google quick view too)
http://www.gwtusa.com/ic/ic/MH-183.pdf

[compfranon]

Compfranon- Well at 100 magnets for 5 pounds you could always give them a shot and find out.

They are Nd magnets, ie rare earth very high strength so they would not be my first choice. But, they are very small, so they might be workable at the right distance. At least because of the small size they would be very easy to work with, just drill a tiny hole in something and a spot of glue holds the magnet in.

If you use a weaker magnet and put it closer you get better accuracy. You can get weaker magnets cheap anywhere, like those plastic fridge magnets in the supermarket. Most have a round button magnet about 10mm diameter that is ideal, look for the older style black ferrite type magnet not a shiny nickel coloured one.

Thanks for the info, I hadn't picked up on the "weaker" magnet preference.