ArcOK when not built-in

I have donevthe reading and understand the reed switch approach. I have even tested that setup to prove to myself it will work.

However it feels some what “hacky”. I was wondering if using a sensor such as this dc current sensor would not be an option?

When reading the items description please also refer to the photos. This is a DC sensor not an AC only as some of the text implies.

Thanks for your thoughts.

Cheers - J.

Another not so "hacky" DIY approach you could try is to grab a ferrite ring large enough for the ground lead to pass through. Cut a slot in it and glue in a hall effect sensor like this
www.jaycar.com.au/ugn3503ua-hall-effect-sensor/p/ZD1902

You can grab some plastic rod and machine a housing for it to make it all neat.

I did make one of these but the plasma cutter died so I never used it.


Beefy has used an ACS758 current sensor which you can buy as a prebuilt module on ebay, Add to that a LM358 small signal amplifier (also available as a prebuilt module) to step up to say 24 volts and read it on a 7i76e analog input.

Thanks for the replies. I appreciate you sharing you experience.

When you guys refer to reed switches I assume you mean the reed side of these types of parts and not the little glass ones.
www.jaycar.co.nz/miniature-security-alarm-reed-switch/p/LA5074 Or
www.jaycar.co.nz/security-alarm-reed-switch/p/LA5072

The dc sensor looks like a potentially slick way of doing things but the more i look at this and reading your comments, just getting a spare earth lead i can dedicate to the table and do the reed swtch wrapped in lead. Its sounding like it will be the simplest, cheapest and probably robust option. I can bundle it all up in some plastic tube or a small plastic box to make it all tidy.

Essentially over engineering this isn’t going to gain you anything, at least that I can see.

Cheers.

You might find that the plasma cutter has a neat one internally. Picture shows tight coil of copper with a reed switch glued in on the ground side. Ideal really...

I didn't end up using it but expect would be highly reliable

phillc54 wrote:

I am pretty sure they the type that Clive used here:

linuxcnc.org/docs/devel/html/plasma/qtpl....html#qt_reed-arc-ok

Yes to confirm I used a glass one from an alarm contact fitted inside a bit of plastic tube with about 3 turns of the ground clamp cable as shown in the pic

Clive - so did you just use the alarm part as is or did you extract the reed switch from it?

I have a couple of bare glass reed switches that i will need to mount on some perf board to be useable. Easy to do and easy to add some screw terminals. But perhaps not as clean as just using pre built reed side of an alarm switch with screw terminals all ready to go.

Cheers.