I made a hand pulled opto paper tape reader looooooooong ago. Very successful. Clocked by extra opto on "feed" sprocket holes. Used small photo transistors and AFAIR background lighting arranged for the purpose. Hand fed - smoothness was a good idea but speeds as fast as you could pull it were successful. Lets see - say it was 1m/sec. That about 3.28*12*10*8 = over 3000 bits per second. Double this at 2m/second! - Wow that's fast! Remember that back then the alternative's were 110 baud teleprinters and 75/1200 baud modems and maybe the new fangled 300/300 modems and ... . For amateur use 3000 baud was superb. My Masters thesis project output data on papertape (Motoroal MC6800 powered :-)) and it was input to the university computer (Burroughs B110 rings a bell). This was trailing edge for them but was the only way that I could interface between the two. I found the papertape punch at the local dump and resurrected it :-) RM _____________________________ What can one man do? Help the hungry at no cost to yourself! at http://www.thehungersite.com/ -----Original Message----- From: Mark Willis To: PICLIST@MITVMA.MIT.EDU Date: Tuesday, 28 September 1999 07:34 Subject: Re: [OT?] Retro-Computer >Paper Tape reader. Try getting a set of opto-isolators, and making your >own; One opto clocks the whole rig, off the "sprocket" hole, software >PLL the whole thing off that hole, use floppy drive type stepper motors >to spin the takeup reel, and it should work fine, I'd think. An 'F84 >should do that easily (just don't rip the paper tape in half - used to >be able to get pretty high speeds off mylar tape this way, beat a KSR/33 >) > >Paper tape punches, could make your own similarly, I'd think; Should be >able to find a KSR/33 (or ASR/33 or ???) for not too much, though, at a >hamfest or surplus equipment sale or ??? I haven't been looking, for >those or for card punches, the local U.W. CDC machines were thrown out >in pieces about 1982 or so, sadly (What a fun toy a Cyber would make!