I'm a programmer, and I usually hang out over on stack overflow, but I have a electricity question.
I'm trying to interact with an APP on my phone by indirectly touching the the screen. Modern touchscreens, as I'm sure everyone here knows are capacitive rather than resistive, so that means that I should be able to interact with it as long as I can bring a small current to the screen where I want to touch.
I'm experimenting with using some speaker cable and a couple other wires I have laying around the house to see how far away I can be and still pass enough current through the wire to register a touch on the screen, based on my distance and the size and quality of the wire.
What I'm finding though is that touching wire to the screen seems to register a touch even without me touching the wire. So is there already a current inside wire? Is it the type of wire I am using? I was under the impression that a wire on its own had no current and only passes electricity when there is an outside source.
Is there anything I can do to decharge the wire, or block it somehow?
Thanks for everyone for letting me know how exactly capacitive touchscreens work. I had it wrong in my head.
The problem that I'm trying to solve is that I want to interact with my phone through its touchscreen from a distance. Is there any material I can use to attach to my phones screen that will essentially extend the touchscreen to where I am? I will only be a few feet out of reach, and it doesn't need to be fancy, just basically detect a touch event.
I realize it might be a strange question, so if I don't get any answers to this I will still choose an answer below, I've learned a lot from this question already.
Answer
so that means that I should be able to interact with it as long as I can bring a small current to the screen where I want to touch.
No. You don't "bring" current to the device. These devices measure capacitance, not current or voltage. The additional capacitance thru your body back to ambient or circuit ground is detected by looking at how the capacitive pad responds to some specifically chosen signals.
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