Stylus - "NonHuman Touch" - HELP

[domerj]

I am working with a group of students on an Educational Robot Cell. We are trying to have the robot pick up a 3D printed Stylus using a vacuum and have the stylus turn music on and off using an Ipod Touch 2nd Gen...

We have tried multiple versions with little luck thus far. Our latest has a small watch 1.5v batter wired to the rubber tip - which works on my Samsung Galaxy S4 - but does not work on the Ipod...

There is no metal connection between the robot and stylus. Stylus is plastic. The rubber tip is from a purchased Walmart Stylus.

How do we get a stylus to work when not using a human to hold it???

 

[Someone Somewhere]

Does it work when a human is holding it? Usually, cheap styluses are only for resistive touch displays. That device uses a capacitive display.

Something flat, metal, and fairly large is usually good. The end of a AAA battery worked well for me, though I don't have an apple device to test it on.

 

[domerj]

So - how do I get the concept of the negative AA Battery to work without holding the battery? I extended the positive and negative leads from a small 1.5v battery into the rubber tip of a stylus and it does not work. I am getting 1.5 volts at the leads under the rubber. Do I just send the negative lead up? or am I missing something?

The AA Battery wrapped in tape and held by me does work on the Ipod Touch... also works on my samsung Galaxy S4. - but it is a large end and difficult to touch just one icon... I can 3D print a holder to set screw a AA Batter into it as the stylus, but is there a way to get to the rubber tip or something with the battery in line?

 

[Someone Somewhere]

No need for the actual battery-ness of a battery. I'm just using it because it's round, metal, and about the right size. A flat screw-head should also work.

You need to actually touch the metal object to the screen (or at least get within ~0.5mm). Wires going back to it don't work, because it's looking for the size.

A resistive stylus designed for screens based purely on force is unlikely to work well with a capacitive screen.