Spoofing a capacitive light switch

[Matt Feifarek]

Hi gang.

I bought a floor lamp that has a capacitive on/off switch.

But I was hoping to switch it on/off with a switched outlet. The switch doesn't remember its state when the power goes off.

Is there something I can tape to the switch (or some such) to make it think a hoo man is poking at it at all times?

(It looks non-trivial to get the switch apart without breaking it or the lamp stalk)

--

Matt Feifarek

+1.608.403.5432 phone / SMS / Signal / WhatsApp

mattfeifarek.com

[Davie]

If a hot dog will trigger the saw stop will it also trigger your lamp? I know that is a terrible long term solution but that's all I've got
--
Sent from my pocket

[Matt Feifarek]

That's definitely a pre-alpha mvp sort of solution.

(thanks for the lol)

[Chris Meyer]

Is the lamp body metal/exposed? 

Capacitive devices detect a loss of charge from the plate, so you need a large enough capacitive body to draw off the charge.  For instance touching it with a piece of metal won't do it, but if you touch the metal that touches the switch plate it'll trigger because the surface area of your body is enough to steal the charge from the plate.  If the lamp body is metal around the switch contact area you could get some conductive adhesive grounding tape (foil tape won't do it, needs to have adhesive that can carry a charge) and tape across the contact area and the lamp body.  You can test this with aluminum foil or a piece of wire to bridge from the plate to the body.

In short I'd take a very close look at your lamp and figure out how to take it apart so you can bypass the switch :-)

Chris

--
You received this message because you are subscribed to the Google Groups "Sector67 Public" group.
To unsubscribe from this group and stop receiving emails from it, send an email to sector67+u...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/sector67/CAM3Y2CLeb39QMqOJkSOoOLiTLpEfoz9cW47bJaJABEXvVg8-Ew%40mail.gmail.com.

[Davie]

If you do dummy the switch then there is a descent chance you will make a strobe light unless you only dummy it on startup.
I expiremented with adding a remote switch to a touch lamp when I was a kid by taping a wire to it and running that to the door way. It had 3 levels of brightness that you switched through by touching the base and if you held your hand on there it would just roll through the options continually.

--
Sent from my pocket

[Charles Cowie]

I have taken apart a number of very old and not so old lamps. They have tended to be somewhat of a pain but manageable. I have sometimes resorted to tricks like counting how many turns it took to unscrew parts with wires inside in order to pre-twisting the wires counter clockwise prior to assembly to avoid tightly twisted wires when re-assembling. Some newer lamps have parts that are easy to damage by over-tightening.

[Matt Feifarek]

I should have mentioned that I did touch the button and the lamp tube with a wire; no dice. But I actually think there is a clear-coat on the lamp that might be preventing conduction.

And maybe the "button" has a plastic covering; my understanding is that capacitance would still work then.

To view this discussion on the web visit https://groups.google.com/d/msgid/sector67/CA%2BMP_mG2kVX7%2Bq7t%2B4uybyobFHK%2BuqvQ4b9yH%3DFajB67RCHg8g%40mail.gmail.com.

[Dithermaster]

I don't think anything static will make it work. Most cap touch systems calibrate on power-up (and over time) assuming they are mostly not touched. You can test this by holding your finger on the touch switch with the lamp unplugged and have someone plug it in. Does it work?

I'd also suggest opening the lamp and bypassing the touch switch. If you ever need it switched again you can reverse that or add a cord switch.

///d@

To view this discussion on the web visit https://groups.google.com/d/msgid/sector67/CAM3Y2CLE8hGZnteO7F-QL9cJf43_VG5V_wPyPrHYfRwYLUJ1HQ%40mail.gmail.com.

[Matt Feifarek]

For those who have a side-wager going on this thread, Dennis is the winner. Lamp definitely doesn't come on with mains power when a meat stick is touching the switch.

I didn't even get to test the hot dog trick.

To view this discussion on the web visit https://groups.google.com/d/msgid/sector67/CA%2BmXBqAaxm_hQ-7m%3DQ-p%3DqZQ9MA9HpmefQ%2BOXsVGBFLkvu5-TA%40mail.gmail.com.

[Dithermaster]

Woot! Extra rations for me this weekend!

///d@

To view this discussion on the web visit https://groups.google.com/d/msgid/sector67/CAM3Y2CLg-C6T_qBVVBAu2kJCaeS02KNTyLocf%2BkOosLoRHmMoQ%40mail.gmail.com.