Magnetic "machine light"

It would be ideal for small lathes. Plenty of steel to stick it onto.

Big Clive

I got worried when you said you thought this might be used on a lathe and then changed your mind because that's exactly where mine's been for the last few months... http://www.stochasticgeometry.ie/wp-content/uploads/2020/09/2020-08-22-14.34.53a.jpg Mine doesn't come with the same cable and the case's switch is slightly different but apart from that it's identical to the PCB (I ordered a second one which arrived DOA so I'd torn it down to see if I could fix it). It's been a nice little light, and I have managed to shove it into the lathe's chuck at a few hundred rpm accidentally and it survived. For the price, I've been very happy with it (especially since I have a small COB floodlight in the corner helping out with spot illumination).

Mark Dennehy

Just looked up the cable spec: (comment written after first mention of the cable - apologies, you mentioned this later on!) "CSA TR-64 wire is a type of hook-up wire that is commonly used for the internal wiring of various kinds of electrical equipment. CSA TR-64 wire is typically rated for a maximum of 300 volts and a temperature range of 80°C to 105°C." So it looks like they've missed a ZERO on the 30V? Bit strange though; must be a cheap copy of the cable even!!

Stephen Eyles

The stud doesn't protrude into the PCB area. It's plastic insert area does.

Big Clive

Testing continuity between the small stud and the magnet would be interesting. If they are connectet, that puts potential live voltage on any metallic surface its is stuck to. RCD should trip instantly, however, if said surface is earthed.

Can you send a picture of them to bigclive1@gmail.com

Big Clive

just looking at a few of these on ebay, seems they also do a version with crimp on connectors for screw terminals. presumably you would wire it in to the machines existing wiring.

Kate Cole

Hi Clive, I have a few old traffic light switching boards at home, I could send you one or 2 if you are interested and the postage isnt unreasonable. (I live in Germany)

I was relieved to find it's a dropper. Neodymium magnets can play havoc with ferrite transformer cores unless you screen them with a backbar. They have a wide BH curve ie a lot of "reach". Relay coils, too.

Mike Page

That’s very cool Jonas 🧲👍

Cerity

I created a simulation circuit for this.. Had to increase the dropping capacitor to almost double to get the desired amperage through the 100 ohm resistor. The whole thing became too slow with 30 leds so I tweaked each led to be nominal 28V 13.66mA instead. https://tinyurl.com/y9ry7el5

Jonas

I just checked. Still useful light, but only 0.6W

Big Clive

It does indeed. It recently surfaced.

Big Clive

A resistor dropper would mainly produce more heat and make small products likely to fail quickly. If you have enough space and a metal housing then a resistor dropper would work as well. But not in small plastic cases.

Sorry if this has been answered 100 times already.. A lot of these circuits being torn apart seem to have "capacitor droppers" — I guess it is because they are the cheapest. 1. But are they inherently bad? 2. Would a resistor dropper be worse/better? 3. Do they waste more energy than other solutions? 4. Or would using more components actually be worse for the environment than wasting a bit of energy? 5. They cause the power factor to be "bad" — does it end up making you pay for 12W even when they only consume 1.5W? 6. Would it make sense/be possible to add a inductor to improve the power factor?

Jonas

I have one exactly like that, the label reads: 110-250v, even though it has that US plug, it works fine on 220V. It has been working fine for several years already. I stick it to my metal desk, and use it while soldering. Since the power cable is a bit flimsy, I need to take care to keep it out of the way of anything that might accidentally melt or cut it.

Willem Hengeveld

Just wondering if your "gadget mountain" includes the WPC-10 Digital Water Pressure Switch? I suggested it a couple years ago, and you responded that you had ordered it.

Paul Malloy

Did you test these with a 110v supply?

Mike Hanley

"While raking through the gadget mountain in a vague attempt to make it manageable"... this made my day, many thanks!

Hagen

Connector... LOL

Michael Thompson

About a foot (300mm).

Big Clive

...reliable from a technical perspective ⁉️ how far inside the pile was this treat🎊😂 Thanks for sharing BC❤️

Cerity