Morgan here from MOTO. Yep, I’m the guy in the video. It’s amazing to see such an active discussion around this simple set of images. Thanks for blowing this up!

An especially big thanks to those of you who tried it and posted results here!

A lot of folks have raised a lot of interesting points here which merit further discussion. I want to address a few key things:

First of all, we don’t intend this to be a rating of the phones as products. We are looking at touchscreen performance here. I could lecture for hours about the nerdly specifics, but the truth is, we’re just trying to share a DIY approach which consumers can use to get a quick understanding of the performance of devices.

It’s not meant to be journal-quality scientific authorship.

Second, just for the record, I am not an Apple Fanboy. I am greatful to Apple for marketing this stuff so heavily, because it drives competition focused on integrated user experience rather than raw features. As an alum of the glory days of IDEO, I’m into that kind of thing. I use Ubuntu at home, XP at work, have an iPhone, many Zunes, many iPods, Sansas, iRivers, HTC phones, Samsung phones, MIDs, tablets, etc. You name it, I’ve used it, torn it apart, criticized it in frustration, and done my best to understand WHY the designers and engineers who built it made the decisions they did.

I have a Nexus One at the moment, and I’m stoked about it — there are a lot of rough spots, but overall the flexbility and power of Android is really starting to shine for me.

I would like nothing more than to see really high quality, ultra-linear touch solutions from every vendor. In my day-to-day work as a product development consultant, that’s good for everyone.

Here are some good points many of you have made, with my comments to help clarify:

1) “You drew crappy lines!!1!”
Yes, yes I did. If you do it by hand, it doesn’t look pretty. But I promise you, I don’t have a tremor which leads to a perfect 10mm periodicity in the waviness of the motion of my fingers.
The clearly-periodic waviness you see is from the sensors, not my finger.

Maybe next time we’ll show you how we do it for *real*, with the robot sitting behind me in the video, but the idea in this post was to show something you can do on the floor at Best Buy if you’re so inclined.

Try it yourself!

2) “You drew faster on the iPhone!”
In the video, I did. Sorry. But in the images shown in the photos, I didn’t, I swear. I drew so damn slowly in those it was aggravating.

Even if I drew 30% faster in the video, the iPhone sensor samples at a rate about 30% higher than the other devices tested, so it’s still not a horrible error. The linearity demonstration is legit.

Try it yourself!

3) “Software can fix that bad touch data!”
Not necessarily. Depends on why/how it’s bad.

If you have some grounding in remote sensing or signal processing, you know that there are certain limits to how much information you have to work with from a transducer of any sort.
Good algorithms can compensate for weird non-linearities (like, say, wavy lines!) in some situations, but you CANNOT create signal where there is none.

One reason Apple’s touch sensor is so sensitive to light touch is that they use 12V drive versus 3-5V for most solutions on the market right now. It costs more power, but you end up with considerably higher voltages to sense, which means higher fundamental SNR coming out of the sensor. This is a *huge* advantage, and it’s something that any touch vendor COULD do if they wanted to.

4) “Medium touch on Android works as well as light touch on iPhone” (@recharged95)
Yes. This is true. However, really light touch is useful for making flicking around menus and maps feel more fluid — if you have to push against the screen, you have to deal with more friction.

You can certainly design your UI around the flaws in your sensing apparatus, like, say, bad edge performance, or bad linearity.
You increase the target sizes, put stuff in the center of the screen, etc.
But you’re paying for that by sacrificing creative freedom.
Every touchscreen should try to be perfectly linear everywhere, so people can build whatever UI they want.

The experience of using a smartphone is the fusion of a massive number of people’s design and engineering expertise — typically a team of 50-200 people or more, when you start counting the design teams at the big ODMs like FoxConn, Quanta, Flextronics, etc.

These products are supposed to be integrated experiences that balance every aspect, from the lightness of touch you can use, to the smoothness of onscreen animation, to bells and whistles like Google Maps and compasses and gyros and accelerometers, too.

Don’t sell yourself short! Demand the best performance from the gadgets you buy in every aspect!

5) “Keyboard performance is hurt more by edge issues than overall linearity issues” (@recharged95) Not enough information here. Honestly, I’ve sat in the user test labs and run these tests. I’ve seen the error rates which real people have on different touch keyboards, and if the data were not proprietary to my clients, I could share examples demonstrating that overall linearity problems with light touch CAN and DO significantly impact typing performance.

A few mm of positional error is a big deal for your key error rate when you’re typing 1000’s of characters.

6) “The lines were fat on the Droid in the video”
Yes they were. Sorry about that. For whatever reason, I couldn’t get the Droid to download the simple drawing app I was using (“DrawNoteK”) until I got to CES and we’d already shot the video with another app (“Draw! Free”).
On the iPhone we used “SimpleDraw”.

The hand-drawing I did on the photos was much more consistent than in the video. It’s still hand-drawing, of course, so verify for yourself if you’re skeptical.

I just got “Simply Draw” on the Nexus One, which I like even better, as it has thinner lines. We’ll probably use that in the future, as it supports multitouch input.

7) “You used different software!”
Yeah, we didn’t have time to fix that in the video. But all the *photos* were done with DrawNoteK on the android devices.

Honestly, I have a pretty refined eye for this stuff, as I’ve written all kinds of SW for data visualization, and I don’t think DrawNoteK or SimpleDraw is doing any major smoothing.
CERTAINLY not to an extent which would hide the waviness we observed.

That waviness is characteristic of the mechanical construction of the touch sensors, which have diamond patterns at a 5mm pitch – you’re seeing the signal waving between diamond rows due to low SNR and imperfect positioning algorithms.

“You excluded the Pre, you insensitive clod!”
I wanted to include it — there’s one by my desk, and I know the team that designed it. But I couldn’t for the life of me find the login credentials for that particular device.
I’ll probably test it next week just for kicks. I might post the result on our labs.moto.com website.

9) “My Pre/Hero/Whatever performed differently and I can prove it!”
Of COURSE it did. You used your finger, your hand, your muscles, your electromagnetic environment, and your device.

The range of finger contact patch size for normal people ranges from about 5mm to about 15mm diameter for those with really big finger pads. It’s wildly organic. Some people drag lightly, some people stab at buttons, some people scrub firmly across the surface. The amount of oil on your fingers varies widely, too — this means different lubrication properties while sliding.

That’s why this is a DIY test!
You really may get great results with a device that I get mediocre ones on!
Try it yourself!

10) “Analog resistive touch screens kick capacitive screen’s ass for linearity”
Hell yes they sure do. And they work great with stylus. The only problems are:

* they don’t do multifinger (do you really care? maybe not…)
* they require force to actuate, so they don’t work as well for light touch flicking-type interfaces
* they have worse optical properties than capacitive screens, because they generally include air gaps

Stantum, TouchCo and others have some interesting stuff to show on the multitouch resistive front, but they don’t fix the no-pressure-required problem. Still, I’m excited to see scanned digital and hybrid systems come to market. It’s gonna be super cool, and will offer some cool differences versus capacitive, especially in the glove/stylus space.

11) “No way! You’re just trying to make the iPhone look better!”
Really, honestly, no. I’m a Freedom and competition guy.

I have played with touch dev kits from *every* other manufacturer, including plenty of stuff that’s not on the market yet, and these wavy artifacts are always a challenge. Apple has been spending a lot of money paying a lot of smart people working on this for a long time.

There’s good news, though: most of the silicon driving these touchscreens is a generation out of date already. The HTC phones only do “1.5 touch” right now — fine for pan/zoom, but not for good rotation or “Ocarina”-style true multifinger input.

Just about everyone will have stuff shipping with true multitouch and much more refined algorithms and sensor designs Real Soon Now, so it’s gonna get better fast.

It’s going to be a great year.

Thanks for listening, and for keeping the pressure on the manufacturers in the blogosphere!