Thursday, January 6, 2011

What is this?

The oStylus, a stylus for capacitive touchscreen devices, already has a website. So what's this blog for?

Good question. My aim is to let you look behind the formal website information to tell you what we are doing and how we are thinking; to allow visitors and buyers of the oStylus to comment; to give some explanations of why things work the way they do. I hope it will also serve as a record of what we have accomplished in a very short time.

It was only about a year ago that I was struggling with drawing on my iPod touch with my finger. I was using the PaintBook app, and getting tired of zooming in and out to enable me to accurately draw a line, placing it where I wanted, and not have my finger constantly in the way of what I was drawing. I also knew that I didn't grow up drawing with my finger — I was always holding a pencil or a crayon or a paintbrush. I knew there were styluses out there, but they all looked and acted like small fingers, blocking the screen. So my first question was: how small can the contact area be and still work?

I'm a jeweller — not a retail jeweller — but a designer, a maker. Most of the jewellery craftspeople I know are great problem solvers. They work with hand tools and machine tools, they know multiple materials and their characteristics (for example I work in silver, gold, plastics, concrete, bronze, paper) and the best ones know metallurgy. They know how wire bends, how metal can be forged or cast. So when I encountered the iPod sketching problem I immediately thought of metal solutions and went to our studio to work it out.

My first attempts were pretty funny. I took 3/8"" brass rod, forged the end flat, bent it and filed it smooth. It had a  primitive-tool feel to it but it worked. I knew the stylus had to be conductive because capacitive screens work by sensing capacitive differences between the screen and the finger. Once I had the smallest possible circle contact working, I realized I wasn't much further ahead than the foam-tipped styluses out there. That's when I hit on the idea of seeing through the contact pad. If I cut out the centre of the circle would it still work? I cut out brass washer shapes and soldered them on the handles, trying different hole sizes and edge thicknesses until I had the best compromise between
    1. being able to see the screen clearly and
    2. still having enough metal to imitate a fingertip.
I ended up with a  stylus that worked. I could see the line as it was being drawn in the opening of the contact pad.

Here's a picture of some of the early experiments from Spring 2010:

Three early prototypes made of brass, copper and various contact materials

I liked what I had developed, and it was usable, but there were still more problems to solve. I'll write about those soon.

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