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Groups > alt.folklore.computers > #155272
| From | Mike Spencer <mds@bogus.nodomain.nowhere> |
|---|---|
| Newsgroups | alt.folklore.computers |
| Subject | Re: 1957 LED |
| Date | 2015-12-16 17:44 -0400 |
| Organization | Bridgewater Institute for Advanced Study - Blacksmith Shop |
| Message-ID | <87k2oem5kw.fsf@bogus.nodomain.nowhere> (permalink) |
| References | <aa4ec05a-2408-4323-b7fe-34d6d61651cb@googlegroups.com> <n4cib8$se5$1@dont-email.me> <396e97cc-39db-46fe-8404-b8c60ec255df@googlegroups.com> <e2d26d9c-7353-4cbb-9c1b-ef85199a2621@googlegroups.com> <sLOdnVJVds5_1_LLnZ2dnUU7-VWdnZ2d@giganews.com> |
Jon Elson <jmelson@wustl.edu> writes: > Quadibloc wrote: > >> On Friday, December 11, 2015 at 8:31:35 AM UTC-7, hanc...@bbs.cpcn.com >> wrote: >> >>> When I was young, the automatic doors in supermarkets were almost >>> all controlled by a pressure-sensitive flood mat. It was very >>> rare to see a door controlled by photo cells. I think today >>> they use a motion sensor, not the floor mat. >> >> I think the popular method is something called "passive infrared". Which >> sounds like a heat sensor. > > No, there really were visible beam systems in use in the 1950's. They had > heavy stainless bars and poles next to the doors, and if you got down low > you could see they had slots in the vertical poles. One side of the "gate" > had an incandescent lamp and a lens in it, the other side had a vacuum > photodiode. There was one store in Concord, NH that had such a setup circa 1950. I was quite taken with it as a smallish child but it was, sadly, a store my mother visited only infrequently MIT has a similar door opener for the big brass front doors on their main building on Mass. Av. I vaguely recall hearing that it was kept in operation because it was the first one of its kind in regular use and MIT was very proud of it. Some MIT grad can perhaps supply the historical facts? -- Mike Spencer Nova Scotia, Canada
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1957 LED hancock4@bbs.cpcn.com - 2015-12-10 11:03 -0800
Re: 1957 LED Al Kossow <aek@bitsavers.org> - 2015-12-10 11:06 -0800
Re: 1957 LED Michael Black <et472@ncf.ca> - 2015-12-10 14:44 -0500
Re: 1957 LED hancock4@bbs.cpcn.com - 2015-12-11 07:41 -0800
Re: 1957 LED Ahem A Rivet's Shot <steveo@eircom.net> - 2015-12-11 16:37 +0000
Re: 1957 LED Michael Black <et472@ncf.ca> - 2015-12-11 14:42 -0500
Re: 1957 LED philo <philo@privacy.net> - 2015-12-10 13:56 -0600
Re: 1957 LED Michael Black <et472@ncf.ca> - 2015-12-10 22:59 -0500
Re: 1957 LED "Osmium" <r124c4u102@comcast.net> - 2015-12-11 08:20 -0600
Re: 1957 LED Michael Black <et472@ncf.ca> - 2015-12-11 14:33 -0500
Re: 1957 LED Quadibloc <jsavard@ecn.ab.ca> - 2015-12-13 07:58 -0800
Re: 1957 LED Michael Black <et472@ncf.ca> - 2015-12-13 13:00 -0500
Re: 1957 LED Lon <lon.stowell@comcast.net> - 2015-12-13 12:48 -0700
Re: 1957 LED Stan Barr <plan.b@bluesomatic.org> - 2015-12-14 09:07 +0000
Re: 1957 LED Michael Black <et472@ncf.ca> - 2015-12-14 11:47 -0500
Re: 1957 LED rpw3@rpw3.org (Rob Warnock) - 2015-12-16 14:55 +0000
Re: 1957 LED Stan Barr <plan.b@bluesomatic.org> - 2015-12-16 16:32 +0000
Re: 1957 LED Michael Black <et472@ncf.ca> - 2015-12-16 14:17 -0500
Re: 1957 LED "Charles Richmond" <numerist@aquaporin4.com> - 2015-12-16 18:15 -0600
Re: 1957 LED Stan Barr <plan.b@bluesomatic.org> - 2015-12-17 07:58 +0000
Re: 1957 LED Andrew Swallow <am.swallow@btinternet.com> - 2015-12-17 13:21 +0000
Re: 1957 LED Ingo Paschke <ipaschke@lpclabs.de> - 2015-12-14 11:11 +0100
Re: 1957 LED Stephen Wolstenholme <steve@easynn.com> - 2015-12-11 10:58 +0000
Re: 1957 LED Lon <lon.stowell@comcast.net> - 2015-12-13 12:50 -0700
Re: 1957 LED Stephen Wolstenholme <steve@easynn.com> - 2015-12-14 12:57 +0000
Re: 1957 LED "gareth" <no.spam@thank.you.invalid> - 2015-12-14 14:07 +0000
Re: 1957 LED Stephen Wolstenholme <steve@easynn.com> - 2015-12-14 14:33 +0000
Re: 1957 LED hancock4@bbs.cpcn.com - 2015-12-11 07:31 -0800
Re: 1957 LED Quadibloc <jsavard@ecn.ab.ca> - 2015-12-13 07:42 -0800
Re: 1957 LED Ahem A Rivet's Shot <steveo@eircom.net> - 2015-12-14 09:39 +0000
Re: 1957 LED Jon Elson <jmelson@wustl.edu> - 2015-12-14 17:07 -0600
Re: 1957 LED Alfred Falk <falk@arc.ab.ca> - 2015-12-15 18:53 +0000
Re: 1957 LED Michael Black <et472@ncf.ca> - 2015-12-15 15:05 -0500
Re: 1957 LED hancock4@bbs.cpcn.com - 2015-12-16 07:32 -0800
Re: 1957 LED Alfred Falk <falk@arc.ab.ca> - 2015-12-16 17:23 +0000
Re: 1957 LED Michael Black <et472@ncf.ca> - 2015-12-16 14:23 -0500
Re: 1957 LED Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2015-12-16 20:13 +0000
Re: 1957 LED hancock4@bbs.cpcn.com - 2015-12-16 13:15 -0800
Re: 1957 LED Michael Black <et472@ncf.ca> - 2015-12-17 14:53 -0500
Re: 1957 LED "Charles Richmond" <numerist@aquaporin4.com> - 2015-12-17 14:17 -0600
Re: 1957 LED Michael Black <et472@ncf.ca> - 2015-12-18 19:43 -0500
Re: 1957 LED "Charles Richmond" <numerist@aquaporin4.com> - 2015-12-20 20:02 -0600
Re: 1957 LED hancock4@bbs.cpcn.com - 2015-12-21 10:31 -0800
Re: 1957 LED Michael Black <et472@ncf.ca> - 2015-12-21 14:53 -0500
Re: 1957 LED mausg@mail.com - 2015-12-21 20:27 +0000
Re: 1957 LED Uncle Steve <stevet810@gmail.com> - 2015-12-17 18:48 -0500
Re: 1957 LED davidmylastname@acm.org (David Griffith) - 2015-12-16 02:43 +0000
Re: 1957 LED Mike Spencer <mds@bogus.nodomain.nowhere> - 2015-12-16 17:44 -0400
Re: 1957 LED scott@slp53.sl.home (Scott Lurndal) - 2015-12-10 19:13 +0000
Re: 1957 LED "gareth" <no.spam@thank.you.invalid> - 2015-12-10 20:17 +0000
Re: 1957 LED Lawrence Statton <lawrence@sengiuo.mx> - 2015-12-10 17:10 -0600
Re: 1957 LED Michael Black <et472@ncf.ca> - 2015-12-10 23:00 -0500
Re: 1957 LED isw <isw@witzend.com> - 2015-12-10 21:21 -0800
Re: 1957 LED Stan Barr <plan.b@bluesomatic.org> - 2015-12-11 08:01 +0000
Re: 1957 LED Michael Black <et472@ncf.ca> - 2015-12-11 14:30 -0500
Re: 1957 LED "Charles Richmond" <numerist@aquaporin4.com> - 2015-12-11 15:36 -0600
Re: 1957 LED Stan Barr <plan.b@bluesomatic.org> - 2015-12-12 07:55 +0000
Re: 1957 LED mausg@mail.com - 2015-12-12 11:20 +0000
Re: 1957 LED Stan Barr <plan.b@bluesomatic.org> - 2015-12-12 15:39 +0000
Re: 1957 LED Michael Black <et472@ncf.ca> - 2015-12-12 10:50 -0500
Re: 1957 LED Stan Barr <plan.b@bluesomatic.org> - 2015-12-13 08:00 +0000
Re: 1957 LED "gareth" <no.spam@thank.you.invalid> - 2015-12-13 11:10 +0000
Re: 1957 LED Lon <lon.stowell@comcast.net> - 2015-12-13 12:51 -0700
Re: 1957 LED "gareth" <no.spam@thank.you.invalid> - 2015-12-11 10:59 +0000
Re: 1957 LED Ahem A Rivet's Shot <steveo@eircom.net> - 2015-12-11 15:46 +0000
Re: 1957 LED "gareth" <no.spam@thank.you.invalid> - 2015-12-11 17:37 +0000
Re: 1957 LED Ahem A Rivet's Shot <steveo@eircom.net> - 2015-12-11 18:34 +0000
Re: 1957 LED Michael Black <et472@ncf.ca> - 2015-12-11 14:49 -0500
Re: 1957 LED "Charles Richmond" <numerist@aquaporin4.com> - 2015-12-11 15:39 -0600
Re: 1957 LED Bob Eager <news0005@eager.cx> - 2015-12-11 22:46 +0000
Re: 1957 LED Michael Black <et472@ncf.ca> - 2015-12-11 19:07 -0500
Re: 1957 LED Bob Eager <news0005@eager.cx> - 2015-12-12 01:04 +0000
Re: 1957 LED Ahem A Rivet's Shot <steveo@eircom.net> - 2015-12-12 08:54 +0000
Re: 1957 LED hancock4@bbs.cpcn.com - 2015-12-11 11:52 -0800
Re: 1957 LED "Charles Richmond" <numerist@aquaporin4.com> - 2015-12-11 15:46 -0600
Re: 1957 LED Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2015-12-11 22:56 +0000
Re: 1957 LED "Charles Richmond" <numerist@aquaporin4.com> - 2015-12-11 15:35 -0600
Re: 1957 LED Quadibloc <jsavard@ecn.ab.ca> - 2015-12-13 07:51 -0800
Re: 1957 LED Lawrence Statton <lawrence@senguio.mx> - 2015-12-10 17:09 -0600
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