Re: Touchscreen requirements
On Tue, Jun 8, 2010 at 2:23 PM, John Watlington w...@laptop.org wrote: On Jun 8, 2010, at 9:03 AM, Bert Freudenberg wrote: Thanks for inviting discussion! I recently started testing Etoys on the Apple iPad - not the least to get an idea of what needs to be done to it for an XO tablet. Multi-touch is definitely cool, e.g. you can move around multiple Etoys objects simultaneously. If you are interested, I can send you a test version (pm me). Etoys uses the Sugar tool bar on all platforms. That works very well, the buttons are large enough even for my fingers. However, many other Etoys UI elements are much too small for touching. They're finicky even on the XO screen, but with a pointer you can at least hit them. That's rather hard with a finger (though the Apple touch screen is amazingly precise). A stylus would be preferable, but then, two-finger gestures are awkward with a stylus. We aren't planning to provide a stylus (just something for the kids to loose), but with some touchscreens any pointed stick can be used as a stylus if needed. The projected capacitance touchscreens becoming popular (iPhone, iPad), on the other hand, don't support just any old stylus, it has to have a special tip. It would help if the tablet had a 4:3 ratio. Ideally 1200x900 pixels just like the XO, but at least preserve the ratio. The iPad has 1024x768 pixels and I made Etoys use a virtual 1200x900 screen hw-scaled to the actual screen size, looks very nice. The aspect ratio of a tablet device is the source of much debate these days.16:9 displays are cheaper due to volume sales, but many (most ?) people around OLPC prefer 4:3. iPad is 4:3, more could follow, so I guess you're referring to PixelQi's current customers? - 1) Number of simultaneous touches: The number of simultaneous touches that can be tracked. For W7, this is two. I believe OLPC is looking for more. IMHO multi-touch is almost essential on a tablet. Two would be enough IMHO, more are nice. What's W7? Windows 7 I listed M$'s specifications as most vendors are trying to meet them. 2) Behavior when number of simultaneous touches is exceeded: If the number of simultaneous touches is exceeded, what happens ? I suggest that the oldest touch be forgotten and no longer tracked, but have seen other behaviors as well. I'd rather keep tracking the first touches and ignore additional ones. Then accidental touches wouldn't interrupt the current interaction. Interesting point. 3) Palm rejection: A number of vendors include palm rejection algorithms in their controllers. I'm not sure how I feel about this --- I would prefer to push this information higher in the stack before discarding it... I would love this on the touchpad of the 1.5 XO also. I keep having problems of jumping cursor when I'm clicking on the pad's buttons. 4) Sensor size: This applies to multizone resistive touchscreens, which may be thought about as a number of small touchscreens, each capable of a single touch.Two touches cannot be detected in any one zone, so this affects how close buttons which might be pressed simultaneously (think piano keys) can be placed to one another. W7 specs 1 in. x1 in. max. I believe this needs to be closer to 1 cm x 1cm max. I'm imagining to use a two-finger tap to invoke meta operations, like the right touchpad button in Etoys on the XO. For this it would need to detect two kid's fingers form one ... Getting closer than 1 cm x 1 cm would probably rule out multi-zone resistive. But a 1 cm^2 zone would probably work fine for two finger tap, even with kid's fingers. 5) Resolution: Do we need to have a touch resolution equal to the screen size ? I have no real experience with this yet, but it needs to be high enough to allow drawing. I didn't list W7's specs for this: 2.5mm accuracy for single touches, and 5mm accuracy for multiple touches An interesting effect I've noticed is that with some touchscreen, you get smooth lines when moving your finger at a normal speed, say 8 cm/s, but when you slow down (1 cm/s) the line wiggles around. 6) Scan rate: The number of times a second that the touch controller can identify and report a touch.W7 specifies 50 Hz minimum, which seems a little high. 7) Robustness: This is usually specified as the number of presses in one spot with a contact area of either 8mm (finger) or 0.8mm (stylus). Industry standard for resistive (single or multizone) seems to be around 80K, which is too low for our needs (we try to reach a 2000 day lifetime). But the one vendor supporting 250K touches was unusable by a bare finger (needed fingernail or stylus). Not that the 250K touchscreen probably needs it... but will the other one be replaceable, if necessary? Best regards, Tiago 8) UV resistance: Since this touchscreen is on top of a sunlight readable
Touchscreen requirements
OLPC is looking to add multi-touch to our interface over the next year --- it is certainly necessary for a tablet. But multi-touch describes a huge range of parameters. Before taking a first pass at a spec. document, I'd like to stir up some discussion. Here are the parameters that I think should be specified. Feel free to comment on them as well as suggest others! Cheers, wad - 1) Number of simultaneous touches: The number of simultaneous touches that can be tracked. For W7, this is two. I believe OLPC is looking for more. 2) Behavior when number of simultaneous touches is exceeded: If the number of simultaneous touches is exceeded, what happens ? I suggest that the oldest touch be forgotten and no longer tracked, but have seen other behaviors as well. 3) Palm rejection: A number of vendors include palm rejection algorithms in their controllers. I'm not sure how I feel about this --- I would prefer to push this information higher in the stack before discarding it... 4) Sensor size: This applies to multizone resistive touchscreens, which may be thought about as a number of small touchscreens, each capable of a single touch.Two touches cannot be detected in any one zone, so this affects how close buttons which might be pressed simultaneously (think piano keys) can be placed to one another. W7 specs 1 in. x1 in. max. I believe this needs to be closer to 1 cm x 1cm max. 5) Resolution: Do we need to have a touch resolution equal to the screen size ? 6) Scan rate: The number of times a second that the touch controller can identify and report a touch.W7 specifies 50 Hz minimum, which seems a little high. 7) Robustness: This is usually specified as the number of presses in one spot with a contact area of either 8mm (finger) or 0.8mm (stylus). Industry standard for resistive (single or multizone) seems to be around 80K, which is too low for our needs (we try to reach a 2000 day lifetime). But the one vendor supporting 250K touches was unusable by a bare finger (needed fingernail or stylus). 8) UV resistance: Since this touchscreen is on top of a sunlight readable display, it will need to be UV resistant. Our current standard (for the display) is no significant change (5%) in optical properties after 4000 hours of full sunlight UV irradiation. 9) Humidity, temperature: Same as the XO: operation from 0 to 50C, in RH up to 95%. Regards, wad ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: Touchscreen requirements
On 08.06.2010, at 07:44, John Watlington wrote: OLPC is looking to add multi-touch to our interface over the next year --- it is certainly necessary for a tablet. But multi-touch describes a huge range of parameters. Before taking a first pass at a spec. document, I'd like to stir up some discussion. Here are the parameters that I think should be specified. Feel free to comment on them as well as suggest others! Cheers, wad Thanks for inviting discussion! I recently started testing Etoys on the Apple iPad - not the least to get an idea of what needs to be done to it for an XO tablet. Multi-touch is definitely cool, e.g. you can move around multiple Etoys objects simultaneously. If you are interested, I can send you a test version (pm me). Etoys uses the Sugar tool bar on all platforms. That works very well, the buttons are large enough even for my fingers. However, many other Etoys UI elements are much too small for touching. They're finicky even on the XO screen, but with a pointer you can at least hit them. That's rather hard with a finger (though the Apple touch screen is amazingly precise). A stylus would be preferable, but then, two-finger gestures are awkward with a stylus. It would help if the tablet had a 4:3 ratio. Ideally 1200x900 pixels just like the XO, but at least preserve the ratio. The iPad has 1024x768 pixels and I made Etoys use a virtual 1200x900 screen hw-scaled to the actual screen size, looks very nice. - 1) Number of simultaneous touches: The number of simultaneous touches that can be tracked. For W7, this is two. I believe OLPC is looking for more. IMHO multi-touch is almost essential on a tablet. Two would be enough IMHO, more are nice. What's W7? 2) Behavior when number of simultaneous touches is exceeded: If the number of simultaneous touches is exceeded, what happens ? I suggest that the oldest touch be forgotten and no longer tracked, but have seen other behaviors as well. I'd rather keep tracking the first touches and ignore additional ones. Then accidental touches wouldn't interrupt the current interaction. 3) Palm rejection: A number of vendors include palm rejection algorithms in their controllers. I'm not sure how I feel about this --- I would prefer to push this information higher in the stack before discarding it... 4) Sensor size: This applies to multizone resistive touchscreens, which may be thought about as a number of small touchscreens, each capable of a single touch.Two touches cannot be detected in any one zone, so this affects how close buttons which might be pressed simultaneously (think piano keys) can be placed to one another. W7 specs 1 in. x1 in. max. I believe this needs to be closer to 1 cm x 1cm max. I'm imagining to use a two-finger tap to invoke meta operations, like the right touchpad button in Etoys on the XO. For this it would need to detect two kid's fingers form one ... 5) Resolution: Do we need to have a touch resolution equal to the screen size ? I have no real experience with this yet, but it needs to be high enough to allow drawing. 6) Scan rate: The number of times a second that the touch controller can identify and report a touch.W7 specifies 50 Hz minimum, which seems a little high. 7) Robustness: This is usually specified as the number of presses in one spot with a contact area of either 8mm (finger) or 0.8mm (stylus). Industry standard for resistive (single or multizone) seems to be around 80K, which is too low for our needs (we try to reach a 2000 day lifetime). But the one vendor supporting 250K touches was unusable by a bare finger (needed fingernail or stylus). 8) UV resistance: Since this touchscreen is on top of a sunlight readable display, it will need to be UV resistant. Our current standard (for the display) is no significant change (5%) in optical properties after 4000 hours of full sunlight UV irradiation. 9) Humidity, temperature: Same as the XO: operation from 0 to 50C, in RH up to 95%. Regards, wad No opinion on these issues, yet ... - Bert - ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: Touchscreen requirements
On Jun 8, 2010, at 9:03 AM, Bert Freudenberg wrote: Thanks for inviting discussion! I recently started testing Etoys on the Apple iPad - not the least to get an idea of what needs to be done to it for an XO tablet. Multi-touch is definitely cool, e.g. you can move around multiple Etoys objects simultaneously. If you are interested, I can send you a test version (pm me). Etoys uses the Sugar tool bar on all platforms. That works very well, the buttons are large enough even for my fingers. However, many other Etoys UI elements are much too small for touching. They're finicky even on the XO screen, but with a pointer you can at least hit them. That's rather hard with a finger (though the Apple touch screen is amazingly precise). A stylus would be preferable, but then, two-finger gestures are awkward with a stylus. We aren't planning to provide a stylus (just something for the kids to loose), but with some touchscreens any pointed stick can be used as a stylus if needed. The projected capacitance touchscreens becoming popular (iPhone, iPad), on the other hand, don't support just any old stylus, it has to have a special tip. It would help if the tablet had a 4:3 ratio. Ideally 1200x900 pixels just like the XO, but at least preserve the ratio. The iPad has 1024x768 pixels and I made Etoys use a virtual 1200x900 screen hw-scaled to the actual screen size, looks very nice. The aspect ratio of a tablet device is the source of much debate these days.16:9 displays are cheaper due to volume sales, but many (most ?) people around OLPC prefer 4:3. - 1) Number of simultaneous touches: The number of simultaneous touches that can be tracked. For W7, this is two. I believe OLPC is looking for more. IMHO multi-touch is almost essential on a tablet. Two would be enough IMHO, more are nice. What's W7? Windows 7 I listed M$'s specifications as most vendors are trying to meet them. 2) Behavior when number of simultaneous touches is exceeded: If the number of simultaneous touches is exceeded, what happens ? I suggest that the oldest touch be forgotten and no longer tracked, but have seen other behaviors as well. I'd rather keep tracking the first touches and ignore additional ones. Then accidental touches wouldn't interrupt the current interaction. Interesting point. 3) Palm rejection: A number of vendors include palm rejection algorithms in their controllers. I'm not sure how I feel about this --- I would prefer to push this information higher in the stack before discarding it... 4) Sensor size: This applies to multizone resistive touchscreens, which may be thought about as a number of small touchscreens, each capable of a single touch.Two touches cannot be detected in any one zone, so this affects how close buttons which might be pressed simultaneously (think piano keys) can be placed to one another. W7 specs 1 in. x1 in. max. I believe this needs to be closer to 1 cm x 1cm max. I'm imagining to use a two-finger tap to invoke meta operations, like the right touchpad button in Etoys on the XO. For this it would need to detect two kid's fingers form one ... Getting closer than 1 cm x 1 cm would probably rule out multi-zone resistive. But a 1 cm^2 zone would probably work fine for two finger tap, even with kid's fingers. 5) Resolution: Do we need to have a touch resolution equal to the screen size ? I have no real experience with this yet, but it needs to be high enough to allow drawing. I didn't list W7's specs for this: 2.5mm accuracy for single touches, and 5mm accuracy for multiple touches An interesting effect I've noticed is that with some touchscreen, you get smooth lines when moving your finger at a normal speed, say 8 cm/s, but when you slow down (1 cm/s) the line wiggles around. 6) Scan rate: The number of times a second that the touch controller can identify and report a touch.W7 specifies 50 Hz minimum, which seems a little high. 7) Robustness: This is usually specified as the number of presses in one spot with a contact area of either 8mm (finger) or 0.8mm (stylus). Industry standard for resistive (single or multizone) seems to be around 80K, which is too low for our needs (we try to reach a 2000 day lifetime). But the one vendor supporting 250K touches was unusable by a bare finger (needed fingernail or stylus). 8) UV resistance: Since this touchscreen is on top of a sunlight readable display, it will need to be UV resistant. Our current standard (for the display) is no significant change (5%) in optical properties after 4000 hours of full sunlight UV irradiation. 9) Humidity, temperature: Same as the XO: operation from 0 to 50C, in RH up to 95%. Regards, wad No opinion on these issues, yet ... Keep experimenting! Thanks, wad ___ Devel mailing list Devel@lists.laptop.org
Re: Touchscreen requirements
I'd rather keep tracking the first touches and ignore additional ones. Then accidental touches wouldn't interrupt the current interaction. Interesting point. On an experimental multi-touch kiosk we were working on (and which came to nothing in the end), we found that it was pretty easy to run out of touches (we could only reliably detect 3 or 4 at the time) and that the users were less confused if we kept the established touches and ignored the new ones. But... That was for our main app. We also had a few toy applications to play with this new h/w, one of which was a sort of music keyboard thing. Using that, it turned out that it was better to handle the new touches and discard the old ones when we ran out, as the users expected to hear a new sound when they added a new touch and didn't seem to be too phased by a previous sound disappearing. So, in summary, erm, it depends... For a conventional UI application (if such a thing exists on a multi-touch tablet), I think keeping the established touches is better. But if you are doing some sort of dynamic, interactive UI, then maybe discarding the oldest first is what the users would expect. Just some experiences to consider. I don't know the answer. ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: Touchscreen requirements
On Tue, Jun 8, 2010 at 9:23 AM, John Watlington w...@laptop.org wrote: An interesting effect I've noticed is that with some touchscreen, you get smooth lines when moving your finger at a normal speed, say 8 cm/s, but when you slow down (1 cm/s) the line wiggles around. See http://labs.moto.com/robot_touchscreen_analysis/ Strength of touch also matters a great deal, and there's quite a bit of fudging being done in the hardware tracking algorithms. --scott -- ( http://cscott.net/ ) ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: Touchscreen requirements
On Jun 8, 2010, at 2:28 PM, C. Scott Ananian wrote: On Tue, Jun 8, 2010 at 9:23 AM, John Watlington w...@laptop.org wrote: An interesting effect I've noticed is that with some touchscreen, you get smooth lines when moving your finger at a normal speed, say 8 cm/s, but when you slow down (1 cm/s) the line wiggles around. See http://labs.moto.com/robot_touchscreen_analysis/ Strength of touch also matters a great deal, and there's quite a bit of fudging being done in the hardware tracking algorithms. Great study. What was interesting about that study is that they conflate strength with finger size. On a PC touchscreen these might be the same, but it implies that with kids we will universally see the crappy results of light touch. Time to find a small finger for testing demos... wad ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: Touchscreen requirements
Time to find a small finger for testing demos... wad Those mini cocktail wieners should work. With the added bonus you can eat the testing fingers when you are hunger :-) Jon ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: Touchscreen requirements
The mini cocktail wieners I'm familiar with are still around 8-10mm. I guess I could carve one down and wrap it in plastic... On Jun 8, 2010, at 11:07 PM, Jon Nettleton wrote: Time to find a small finger for testing demos... wad Those mini cocktail wieners should work. With the added bonus you can eat the testing fingers when you are hunger :-) Jon ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: Touchscreen requirements
On Tue, Jun 8, 2010 at 11:14 PM, John Watlington w...@laptop.org wrote: The mini cocktail wieners I'm familiar with are still around 8-10mm. I guess I could carve one down and wrap it in plastic... Gummy fingers are more fun: http://cryptome.info/0001/gummy/gummy.htm --scott -- ( http://cscott.net/ ) ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
