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The Secret Behind the iPod Scroll Wheel
Grump sent in a story saying "Ask any iPod user what they like the most about their device, and most will probably mention the scrollwheel. Here is the story behind the company that makes it (hint: it's not Apple). Great not just for the history, but insight as to both how Apple's design process works, and how the scroll wheel itself works."
This "article" just shows some pictures of what I can only assume is the touch sensitive plates under the wheels. It doesn't explain anything about them and how they work, nor does it really talk about the "design process."
but insight as to both how Apple's design process works, and how the scroll wheel itself works.
The article doesn't say how the scroll wheel works. It also doesn't mention anything about Apple's design process...
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The scroll wheel is just a round touchpad and is based on the same technology Synapsis has patents on. It even feels the same as the touchpad on my PowerBook.
I have a 4th gen iPod with the click wheel and after I finally figured out you just moved your finger to scroll (it wasn't immediately obvious and I've not had the opportunity to use previous versions) I've found it to be far more responsive than the touchpads I've encountered on notebooks. I have a Sony Vaio at work and I hate the touchpad on it, it's very difficult to control and way too sensitive registering double clicks even when my finger doesn't leave the surface. (Apparently pausing with your finger on the touchpad counts, I can't find a way to adjust the settings to fix it.)So I'd have to say that with the current generation clickwheels the touchpad on the iPod is far better. It's just sensitive enough without being too sensitive and it requires no adjustment to work that way. That alone is an achievement since there are so many different finger sizes out there and different people are going to push with different pressures.
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Touchpads are the best thing that ever happened to this company. They're getting licensing fees and royalties on almost every notebook sold, or they make money directly as the component vendor for the touch pads.
And deservedly so, they obviously can make some top notch ones (iPod clickwheel) so they're really earned those fees and royalties. At least they're not an IP company making money via lawsuit....capacitive. It must be, or something fairly similar.
It explains why the human finger can operate the wheel, but drag a BIC biro round the wheel and nothing happens.
It amazes me why they haven't considered making a mouse with this straightened-out version.
You mean like this perhaps?
- sig? who is this sig of which you speak?
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If you haven't yet tried the clickwheel on an iPod yet, do it. The article is handy if you're curious about implementation, but actually using the device to navigate a huge music library will literally make you grin.
Just a bit of testimony on this, up until last week the only encounters I'd had with iPods were store demo models and I couldn't figure the bloody wheel out. I do have to say it's not immediately intuitive, having the clickable buttons threw me off, I thought you used the back and forward ones to navigate the menu. Last week I got an iPod all of my own, a 4th gen one with the clickwheel. After a bit of frustration trying to figure out how to use the clickwheel I finally noticed it moved up and down as my finger moved along it. Bingo, easy to use after that.Based on past experiences I'd not been a fan of the design, but after learning HOW it works and using it I have to say it's exceptionally well designed. It's easy to scroll through the lists and volume control is a breeze. I can even reach down and adjust the volume on it while driving and not have to look at it. I even have to look at the radio to make sure I get the right knob so that's saying something! (Note that I do not listen to it with headphones while driving in the car, I know that's dangers and illegal in most states.)
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Oh, and speaking of iPods, please click the link in my signature
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Take him up on it or even use mine. Find a conga line to help you get your referrals. That's where my iPod came from, amazing to get a free nearly $300 device.I never really thought much of the scroll wheel on the iPod either, but I knew it was just a variation of the track pad like my laptop has (which is also a synaptics).
Presently here, but not there.
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The Pong system is a little different from the scroll wheel in that it senses the ABSOLUTE angle of a variable resistor whereas the scroll wheel detects RELATIVE angle of a rotary encoder. I know because I actually built a PONG system using GI's famous AY chip.
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Technically it's not plagiarism, but quoting. And that is legal, if you keep it to a short blurlb and not the whole text. What would be nice is a short notice like "From the article:" or something.
As someone else mentioned, it's probably capacitance between the pad and your finger. No need for a timer. The pad with the highest capacitance gives you the absolute position of your finger, and the sequence gives you the direction of movement. The pointy shapes no doubt make the capacitance vary more gradually from one pad to the next, so that the absolute position can be determined more accurately by interpolation.
And let's not forget Roland's "Alpha-Dial" that appears on many of their musical instrument products...
I'm pretty sure that what people class as "1st Generation iPod" actually covers two differently-designed scrollwheels, assuming by 1st Gen iPod we're referring here to the ones with the buttons placed round the scrollwheel.
It may well be that the very first 1st Gen iPods used an optical encoder. However, my late-1st Gen iPod (first of the 20Mb models) definitely has some form of touchpad, as the touch ring does not move.
Electronics Design Chain
Bang and Olufsen used the exact same wheel on one of their telephones several years before Apple. While Synaptics might make the technology, and would have had to re-engineer aspects to suit Apple, the design itself is pre-Apple in almost every way. This would be like saying that Apple invented the mouse--they just poularized it.
Actually a rotary phone does not use timing what so ever. The turning of the dial creates a current that is sent up the line. 4 pulses sent for the number 4 and so on. Grabbing the dial and forcing it back to the starting place still sends the correct amount of digits. If you notice when you force a dial on a rotary phone you can only force it so much. The resistance that exist for the whatever mechanics make the current do not allow you to turn it back as fast as you can.
I am sorry but your story is more myth than fact.
Evidence is another reply posted where you can dial a number by clicking the hook over and over again. When you pick up the phone a current is sent up the line to the central office, because you completed a circuit by picking up the phone. The central office provides power down the line as a sort of status check for when you go off hook, hence if you try to lick a phone line you will get a shock. The point being that since you can dial a number by hanging up repeatedly you could not possibly do so in perfect time, therefore timing has nothing to do with it.
The switches that first used pulse dialing were not smart enough the handle timing. Current digital switch that use touch tone don't even use time, they use, that's right, TONES. Two actually per digit.
Imagine the keypad on your phone as a tic tac toe board. Across the top you have three tones (can't remember the freq.) and down the side you have four. The combination of two tones make a digit where they intersect.
Calls used to be switch through the network strictly by the tones. But here comes WOZ (and others) and he figures out how to take advantage of that fact and creates the blue box. Phone companies smartened up and create the SS7 network. Once your tones/digits hit you host office they are removed from the line and you call is setup by a seperate network of routers, switchs, and databased to get you to your destination. If all is clear and your call can complete (lines not busy, trunk facilities available) the switch between caller and callee are nailed up and the call is connected. This is out of band signaling. Cool stuff.
The databases are also what provide 1-800/900 service (dial an 800 number and the DB converts it to an actual POTS number XXX-XXX-XXXX), caller id, local number portability (same as 800 conversion), some verisons of remote call fowarding, and host of other cool things.
Fun with phones. Back to work.
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Standard pulse timing is 10 pps, with a window from about 7.5-12 IIRC. It's been a while since I had to adjust the little mechanical governor that controlled the rotary dial return rate. Duty cycle is 50%. Pulse too slow and it will be mistaken for a hookflash. Too fast and you'll exceed the slew rate of the switch and drop pulses. Mechanical switches are, of course, more succeptible to too-fast pulse rates. Electronic switches can probably accept faster than 12 pps, but 10 is still the standard.
The "turning of the dial" creates no current. It interrupts the circuit. So does the hookswitch, which led to being able to "dial" a phone with the hookswitch. You still had to have good manual dexterity, especially when there were higher numbers in the number you were trying to reach. This was popular in the days when a coin telephone disabled only the dial circuit and not the voice path. Nowadays, of course, you can't do this because the dial tone you hear when you pick up is generated by the phone itself, which accepts your call information and then decides how to route the call.
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The optical sensor that Microsoft's (and others') optical mice use, is made by Agilent. Gary Gordon, who works at Agilent, invented the optical mouse. Microsoft just happens to license the technology.
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Two things..
1. It was based on call volume, not class or priority. The few seconds saved in dialing time to high-volume areas saved a lot of switch wear and tear as the switches were mechanical--moving parts and all. (well, I guess that would be priority).
and 2. I actually live in the 909 you insensitive clod!
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