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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?
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.
Download Mazes and Puzzles from www.puz.com
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.
www.fotoforay.com
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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