# Touch pad using tester logic?

Hi everyone,
I was planning to make a doorbell of which's switch is a touch pad.I tried understanding the logic behind the touch screens used in i phones and such otherd but they seem a bit complicated.Another solution I got was a circuit which has two free wires and when a person touches the two wires(creating contact),the load gets power.This is based on transistor switching.But I don't want to adopt this design since........ I don't know for some reason.Then I remembered those classy electrical testers(seen in the picture).They have a neon bulb in them which glows when they get a voltage of certain range from one end and our body is used as ground when the other end is touched.So if I use this mechanism I just have to use the setting to power the load when a metal plate connected to one end is touched by a 'user'and a voltage is given through the other end.I know these things usually have a neon bulb as they handle AC voltage.Finally here's what I actually need to know-
Is it possible to build such a circuit where a 12 VDC is supplied to one end and the load is given power when the other end meets ground(here the person touching the pad).Maybe this might be a total jabberwocky but anyway contribute your valuable suggestions.If anyone has seen such circuits elsewhere, a schematic could be really helpful.Thank you in advance.

1 year ago
Why over complicate something as simple as a small push button?

You touch it and it activates your door bell. Why make it a touch sensitive anything?

The tester probe won't work. Those are used for mains voltages and the light only needs the Alternating current from the live wire to light up. No ground is needed and it's not really a touch sensor. The metal touches the live wire and the light lights.

You said, "Is it possible to build such a circuit where a 12 VDC is supplied to one end and the load is given power when the other end meets ground." What you just described is a push button or a switch. You touch the button it makes contact with ground completing the circuit and activating your door bell.

What you want to look into is using a pressure sensor with a micro controller like an Arduino. The sensor acts as a variable resistor. The harder it's pressed the lower the resistance is. So have the micro controller read the sensor and if it's in a certain range it knows it's being pressed and to activate the bell. That's about the simplest way you'll get a touch pad like door bell.
The project you link to is just a 12V light connected to a couple of probes. it would be no different than having the probes already connected to the battery and having a push button to close the circuit.