Nope. It's not as complicated at that. In the case of the wand - you sync it yourself by the speed that you move the wand in space. If you move it too fast - all you'll see if a garbled mess. If you move it too slow - you'll see, (yet again), a garbled mess! This one's down to experience - you'll get the hang of it. In the case of the spinning cylinder with the LED's sticking out of the side - it's controlled by the motor. If it spins too fast - you'll see a garbled mess, (don't think I need to say what happens when it goes too slow?!) Cheers, Stuart -----Original Message----- From: pic microcontroller discussion list [mailto:PICLIST@MITVMA.MIT.EDU] On Behalf Of Lindy Mayfield Sent: 23 May 2004 11:54 To: PICLIST@MITVMA.MIT.EDU Subject: Re: [PIC:] Single Row of LED's Illusion - How they do that? Hi, Thanks for everyone's input on this and please one more thing before I let this drop just for my understanding. Just looking at the ad for the waving pen that spells out something and reading everyone's input on the subject comparing it to a dot matrix printer it makes sense to me that the timing of the lights has to be synchronized with the position of the wand in space. So would this mean that in the light pen wand thingy that there is some sort of tilt mechanism there that synchronizes the lights with the speed it is waving back and forth? -----Original Message----- From: pic microcontroller discussion list [mailto:PICLIST@MITVMA.MIT.EDU] On Behalf Of Howard Winter Sent: Sunday, May 23, 2004 12:30 To: PICLIST@MITVMA.MIT.EDU Subject: Re: [PIC:] Single Row of LED's Illusion - How they do that? Lindy, On Sun, 23 May 2004 12:11:15 +0200, Lindy Mayfield wrote: >...< > Sorry, perhaps I wasn't specific about my "idea". (-: I meant I >thought I could maybe do one where you have to look at it and shake your head NO! over and over to read it. No, because although you move your head, your eyes will fix on the spot you are looking at - it's really difficult to get your eyes to scan past something without stopping on the way, so all you'd see is a vertical row of lights varying in intensity. It's a physiology thing - our eyes don't work well when they're moving, so you actually move them in stops & starts, however hard you try to do it smoothly. Added to which you'd have to "scan" at the right rate, and syncronised with (say) the display of the start of the characters, and you'd have no way of doing that. It works exactly the same as a television scan (although with all the rows active at once, rather than sequentially downwards on a television). If the horizontal scan drive failed on a television so you had just a vertical line, there's no way you could see the picture by waving your head about! :-) Cheers, Howard Winter St.Albans, England -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details. --- Incoming mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.663 / Virus Database: 426 - Release Date: 4/20/2004 --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.663 / Virus Database: 426 - Release Date: 4/20/2004 -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details. -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.