For some reason, at night, if I hit my plasma ball hard enough my touch lamp reacts and turns on/off, depending on what state it’s currently in (obviously). Why?
I hope you can help me, it’s bothered me for a good while now.
Jimmy
Touch lamps detect people because they apply a small alternating voltage to a metal object (usually the lamp itself.) They then detect the small changes in voltage caused by contact with another conductive object, such as a human body. A touch lamp is a voltage sensor.
Plasma globes generate an invisible field of alternating high voltage. It’s pretty amazing that the sensor in a touch lamp isn’t totally swamped out by the plasma globe’s intense field. After all, the touch lamp is waiting for tiny voltage changes, not enormous ones.
I bet that the touch lamp is designed to ignore slow changes in voltage, but respond to fast changes. With your hand on the plasma globe, your body acts as an antenna, and the high voltage field will reach much farther out. But if you slowly put your hand on the plasma globe (or slowly remove it), the touch lamp probably is ignoring this slow change.
Here’s an experiment to try. Hold a set of keys, or a quarter, or some other conductive object in your hand. Place a small piece of aluminum foil on top of the plasma globe. Now use the keys (etc.) to touch the foil. The sudden contact will create a sudden change in voltage and might make the touch lamp respond, same as hitting the plasma globe.
Ok, that’s all fine and good, but why will it only work at night? It can’t get it to work during the day and it is pretty spotty at night, too.
I’ll tell you something, though, it gave me quite a scare the first time it happened.
Maybe you have a wiring problem, or are creating a surge by hitting your plasma ball. Maybe it happens at night because you are using more electricity at that time? Or it could be a poltergeist.
Now that’s just weird! No idea.
If you move the plasma globe closer to the touch lamp, results might improve. But if the field overloads the touchlamp sensor, it might stop responding entirely.
See:
Plasma globe circuits & projects
http://amasci.com/tesla/plasplan.html