Well you have some good questions. I don't have the specs for the size of the cell and so forth but there is certainly one. Braille dots are a specific size and a specific distance apart. As for how much pressure the dots have to withstand, I guess the answer is the more the better. In general you want something that can withstand a heavy hand pressing on them. Another consideration is the response time. It needs to be very short. Obviously power is more of a concern for portable siplays. There have been many attempts at making Braille cells with other technologies. I know that people have tried magnets, memory metal, air and rotary actuators in the past. None of these have ever proved to be as practical as the piezo-electric crystals. Tommy -----Original Message----- From: blinux-list-admin@xxxxxxxxxx [mailto:blinux-list-admin@xxxxxxxxxx]On Behalf Of Nick Nelissen Sent: Monday, July 21, 2003 10:49 PM To: blinux-list@xxxxxxxxxx Subject: Re: Papermeier Braillex ELBA note taker Would the power constraint apply to non-portable equipment. I think part of the complexity of the actuator must be either because it locks in place or perhaps because it uses the peizo effect which is very small mechanically and thus requires leverage. As an example a small relay can draw about 20 milli amps at 12 volt which is 240 milli watts. This gives a total consumption for 320 actuators of around 80 watts, just about what a video monitor uses. Actually I may be on the track of something, relay coils may form the basis of an actuator, they are manfuactured in the hundreds of millions. This leads to a number of questions. What percentage of use would require the unit to be portable? If a unit was cheap enough would people buy one with the constraint that it was not portable? is there a specification for the exact dimensions of the cell, that is how far apart can the dots be at most? Thanks, Nick On Tue, 22 Jul 2003 11:13, Dave Mielke wrote: > [quoted lines by Nick Nelissen on July 22, 2003, at 11:20] > > >it would be > >interesting if there is already an actuator out there in some mass > > produced piece of equipment that could be used. > > Another constraint is that each actuator must have a very low power > requirement. A forty-cell display, for example, would have 40x8=320 > actuators. Current displays have battery drain times of 15-30 hours. _______________________________________________ Blinux-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/blinux-list _______________________________________________ Blinux-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/blinux-list