I'm trying to build the smallest possible tangible PDP-1 emulator. My ideal scenario would fit the circuit onto a double-sided 90 x 55mm PCB. Hence, I need to fit 119 lamps (LEDs) and 44 switches into this area. The LEDs are no problem, but are there such things as tiny, tiny slide switches or subminiature DIP switches? The smallest I can find are SMD DIP switches with .050" lead spacing; is there anything smaller than this? (It does not have to be practical. Merely amusing, and theoretically operable).
Ideas for really small slide switches?
Started by ●January 16, 2006
Reply by ●January 16, 20062006-01-16
On 16 Jan 2006 17:18:16 -0800, "larwe" <zwsdotcom@gmail.com> wrote:>I'm trying to build the smallest possible tangible PDP-1 emulator. My >ideal scenario would fit the circuit onto a double-sided 90 x 55mm PCB. > >Hence, I need to fit 119 lamps (LEDs) and 44 switches into this area. >The LEDs are no problem, but are there such things as tiny, tiny slide >switches or subminiature DIP switches? The smallest I can find are SMD >DIP switches with .050" lead spacing; is there anything smaller than >this? > >(It does not have to be practical. Merely amusing, and theoretically >operable).Perhaps by going further and look for a way to include both the light and the switch into a tiny push-button toggle, where appropriate? Something like was used on the HP-2116, for example? Wow, that is small space. Hmm... In the act of "pushing" the switches would it be acceptable to consider finding a way of sensing if an LED is touched or pressed and using the LED itself as sensor as well as display? But I'm no help on tiny switches. Best of luck! Jon
Reply by ●January 16, 20062006-01-16
Jonathan Kirwan wrote:> >The LEDs are no problem, but are there such things as tiny, tiny slide > >switches or subminiature DIP switches? The smallest I can find are SMD > >DIP switches with .050" lead spacing; is there anything smaller than > > Perhaps by going further and look for a way to include both the light > and the switch into a tiny push-button toggle, where appropriate?It isn't archaeologically appropriate for most of them. The PDP-1 front panel has lamps for PC, address, memory, accumulator, I/O. Below that it has switches for address and test word. To the right it has six sense switches and three "other" switches. Below the front panel are eight switches with other functions.> Something like was used on the HP-2116, for example? Wow, that is > small space.It's a standard business card. The idea is to distribute the business card with the DEC press release stating that the PDP-1 occupies a mere 17 square feet of floor space and inviting the recipient to prepare 17 square feet of clear space in which to lay the business card. I've been trying to build this business card computer for ages. I wanted it to be a VIC-20 but I can't ascertain the copyright status of the ROMs. Also I'm not sure I can write a software simulation of the video that will run fast enough for VGA monitor output. (NTSC is a dying standard - I don't want to design for it). I've also considered the ZX-81 and the 48K ZX Spectrum; they also have the video bandwidth problem. I actually asked Amstrad if it is possible to license the Spectrum ROMs for this purpose (their free emulator license specifically disallows hardware implementations).> Hmm... In the act of "pushing" the switches would it be acceptable to > consider finding a way of sensing if an LED is touched or pressed and > using the LED itself as sensor as well as display?Interesting, I didn't consider this as a possibility (mind you I have no idea how it could be done). The idea of using pushbuttons is OK, I guess. I can have an LED by each to indicate if it is off or on.
Reply by ●January 17, 20062006-01-17
On 16 Jan 2006 17:18:16 -0800, "larwe" <zwsdotcom@gmail.com> wrote:>I'm trying to build the smallest possible tangible PDP-1 emulator. My >ideal scenario would fit the circuit onto a double-sided 90 x 55mm PCB. > >Hence, I need to fit 119 lamps (LEDs) and 44 switches into this area. >The LEDs are no problem, but are there such things as tiny, tiny slide >switches or subminiature DIP switches? The smallest I can find are SMD >DIP switches with .050" lead spacing; is there anything smaller than >this? > >(It does not have to be practical. Merely amusing, and theoretically >operable).Look at http://europe.omron.com/Images/en/165_19202.pdf It will occupy around 15% of your surface availble (one side only) for 50 switches Zara
Reply by ●January 17, 20062006-01-17
"larwe" <zwsdotcom@gmail.com> schrieb im Newsbeitrag news:1137460695.985004.217880@g49g2000cwa.googlegroups.com...> I'm trying to build the smallest possible tangible PDP-1 emulator. My > ideal scenario would fit the circuit onto a double-sided 90 x 55mm PCB. > > Hence, I need to fit 119 lamps (LEDs) and 44 switches into this area. > The LEDs are no problem, but are there such things as tiny, tiny slide > switches or subminiature DIP switches? The smallest I can find are SMD > DIP switches with .050" lead spacing; is there anything smaller than > this? > > (It does not have to be practical. Merely amusing, and theoretically > operable). >The 0,050" switches are availlable with j-leads from http://www.copal-electronics.com/e/index_e.html, this saves a lot of space. http://info.tactnet.co.jp/cgi-bin/copal/eprodisp.cgi?pg=0&pk=img&pf=020SWE&pm=SWE002&pn=1 MIKE -- www.oho-elektronik.de OHO-Elektronik Michael Randelzhofer FPGA und CPLD Mini Module Klein aber oho !
Reply by ●January 17, 20062006-01-17
On 16 Jan, in article
<1137460695.985004.217880@g49g2000cwa.googlegroups.com>
zwsdotcom@gmail.com "larwe" wrote:
>I'm trying to build the smallest possible tangible PDP-1 emulator. My
>ideal scenario would fit the circuit onto a double-sided 90 x 55mm PCB.
>
>Hence, I need to fit 119 lamps (LEDs) and 44 switches into this area.
>The LEDs are no problem, but are there such things as tiny, tiny slide
>switches or subminiature DIP switches? The smallest I can find are SMD
>DIP switches with .050" lead spacing; is there anything smaller than
>this?
>
>(It does not have to be practical. Merely amusing, and theoretically
>operable).
Off the wall suggestion - forget mounting switches and use test pads
arranged as switches in SPDT configuration and a small metal stylus
to short to 1 or 0. I do assume you will have a switchscanner in
there in some form of other. This means building up switch patterns
and remembering each switch until an 'action' switch is operated.
Might save a lot of space.
--
Paul Carpenter | paul@pcserviceselectronics.co.uk
<http://www.pcserviceselectronics.co.uk/> PC Services
<http://www.gnuh8.org.uk/> GNU H8 & mailing list info
<http://www.badweb.org.uk/> For those web sites you hate
Reply by ●January 17, 20062006-01-17
Paul Carpenter wrote:> Off the wall suggestion - forget mounting switches and use test pads > arranged as switches in SPDT configuration and a small metal stylus > to short to 1 or 0. I do assume you will have a switchscanner in > there in some form of other. This means building up switch patterns > and remembering each switch until an 'action' switch is operated.The scanning is no problem; as you can see I've already accepted the possibility of using momentary switches (pushbuttons) instead of "real" switches. This issue only affects the 35 switches below the IN-OUT lamps, by the way. The stylus is, however, a problem. If it comes to a point, it's hard to make it contact both sides of the "switch" contacts. If it comes to a flat surface, it needs to be aligned very well by the user so it presses hard enough against both contacts to make a good circuit. (Think of how hard it can be to bridge an 0603 gap with a pair of tweezers sometimes). If I could put a piece of that carbon-impregnated rubber used in dome switches on the end of the stylus, it would probably be OK. BTW I posted links to a couple of pictures, but the message didn't seem to make it to comp.arch.embedded: An old photo of the original: http://www.dbit.com/~greeng3/pdp1/PDP1.10.jpg my current mechanical test layout (missing address and test word switches): http://www.larwe.com/pdpcard.gif and a 1:1 scale printout of the layout in my hand: http://www.larwe.com/PDRM1836.JPG
Reply by ●January 17, 20062006-01-17
(Paul Carpenter) wrote: "larwe" wrote:>>I'm trying to build the smallest possible tangible PDP-1 emulator. >... are there such things as tiny, tiny slide switches >... >Off the wall suggestion - forget mounting switches and use test pads >arranged as switches in SPDT configuration and a small metal stylus >to short to 1 or 0.That's very much on my wall, I was going to suggest something just one step above that. Stack together on an axis a few metallic plates with a profile resembling a switch, and use two pcb's to create a sensor pad on both sides. Something along like this - (sorry for the poor ASCII art): /-----\ + + /-----\ | + + | | | | | | | | | | | | | | | | | | | | | + | | \ x + + + xx / \ | xxx + + | xx | (rotation | | x rubber band to keep | * | + switches centered | axis) | / + + / \ / + \ / | \ / | | || | 1-| || | <--0 | |\---/ 1--> | | <--0 \---/ You can have small parts made a-la-carte here: http://www.emachineshop.com/ Roberto Waltman [ Please reply to the group, ] [ return address is invalid. ]
Reply by ●January 17, 20062006-01-17
On 17 Jan, in article
<1137508774.246339.267310@g47g2000cwa.googlegroups.com>
zwsdotcom@gmail.com "larwe" wrote:
>Paul Carpenter wrote:
>
>> Off the wall suggestion - forget mounting switches and use test pads
>> arranged as switches in SPDT configuration and a small metal stylus
>> to short to 1 or 0. I do assume you will have a switchscanner in
>> there in some form of other. This means building up switch patterns
>> and remembering each switch until an 'action' switch is operated.
>
>The scanning is no problem; as you can see I've already accepted the
>possibility of using momentary switches (pushbuttons) instead of "real"
>switches. This issue only affects the 35 switches below the IN-OUT
>lamps, by the way.
>
>The stylus is, however, a problem. If it comes to a point, it's hard to
>make it contact both sides of the "switch" contacts. If it comes to a
>flat surface, it needs to be aligned very well by the user so it
>presses hard enough against both contacts to make a good circuit.
Well you did say theoretically operable, a bit like the old calculator
watches of 70's/80's era.
>(Think of how hard it can be to bridge an 0603 gap with a pair of
>tweezers sometimes).
And how often how easily a scope earth clip pings off and does it for
you but on the _wrong_ 0603 :-^
>If I could put a piece of that carbon-impregnated rubber used in dome
>switches on the end of the stylus, it would probably be OK.
Well it is an alternative.
>BTW I posted links to a couple of pictures, but the message didn't seem
>to make it to comp.arch.embedded:
Just seen them, PDP-1 was before my computing time I worked on 8's, 11's
micro-11's (various) and VAXes various.
...
--
Paul Carpenter | paul@pcserviceselectronics.co.uk
<http://www.pcserviceselectronics.co.uk/> PC Services
<http://www.gnuh8.org.uk/> GNU H8 & mailing list info
<http://www.badweb.org.uk/> For those web sites you hate
Reply by ●January 17, 20062006-01-17
larwe wrote:> I'm trying to build the smallest possible tangible PDP-1 emulator. My > ideal scenario would fit the circuit onto a double-sided 90 x 55mm PCB. > > Hence, I need to fit 119 lamps (LEDs) and 44 switches into this area. > The LEDs are no problem, but are there such things as tiny, tiny slide > switches or subminiature DIP switches? The smallest I can find are SMD > DIP switches with .050" lead spacing; is there anything smaller than > this? > > (It does not have to be practical. Merely amusing, and theoretically > operable). >Use minature SMD phototransistors, and the slider blocks the ambient light? Adds problems with finger placement during operation, but definitely small and low on the moving-parts count. I guess an equally viable solution would be side-looking SMD IR LED and detector pairs. Though I'm having no luck finding IR side-looking LEDs, and non-IR side-looking phototransistors. You might do better.
