>
> larwe wrote:
>
>> Spehro's suggestion is closest, so far, to what I had in mind.
>> http://www.larwe.com/pdpcard.gif shows a front panel layout that is
>> ALMOST final. The eight control switches are giving me trouble.
>
> Oh, one other thing: A citizen suggested yet another method, which is a
> magnetic stylus and SOT23 Hall effect sensors as the "buttons". I
> rather like this :)
>
Paired up with indicators it could look very switch like including sensing
direction of motion.
--
JosephKK
Reply by ●January 21, 20062006-01-21
Eric Smith wrote:
> I've got it! :-) Make it out of flex circuit, so that it unfolds to
> double size, to reveal the state indicators, sense switches, etc.
That sounds clever.
Now, am I missing something here: how about a DIP switch bank? As once
used on ISA cards to set IRQs etc. Quite practical to operate with a
miniature screwdriver, cocktail stick, etc.
NT
Reply by ●January 20, 20062006-01-20
I wrote:
> What suggestion is that? I don't see anything from him in the local
> news spool the Google Groups archive.
larwe wrote:
> It's in sci.electronics.design, for Alps pushbuttons.
Strange, I still can't find it. Oh well.
The smallest toggle switches I've seen are the ITT Cannon GT series
Sealed Ultraminiature Toggle Switches:
http://www.ittcannon.com/media/pdf/catalogs/Leaf/SW_toggle_gt.pdf
Some of thsoe are only 4.06 mm wide, so you could cram a row of 18 of
them onto an 86 mm wide card with a little room to spare.
Note that having the various indicator rows not line up with the
switches will make it relatively unpleasant to operate.
I've got it! :-) Make it out of flex circuit, so that it unfolds to
double size, to reveal the state indicators, sense switches, etc.
Reply by larwe●January 20, 20062006-01-20
Eric Smith wrote:
> What suggestion is that? I don't see anything from him in the local
> news spool the Google Groups archive.
It's in sci.electronics.design, for Alps pushbuttons.
> Looks fairly nice. If I were doing it, I'd probably just relax the
> size requirement a little.
The business card size is a standard size, and a firm requirement :)
> If those switches are momentary, you're *really* going to need a set
> of LEDs for the address and test word switches. I'm speaking from
Yes, exactly - that's why I say it's not quite final.
> Note that the START switch on the console is an on-off-on momentary, and
> there is a distinction between pressing it up and down, so if you are
The eight switches that go at the bottom (examine, deposit, start etc)
are momentary slide switches on the underside of the board at the
moment. I don't like this arrangement and I'm juggling a bit.
Reply by ●January 20, 20062006-01-20
larwe wrote:
> Spehro's suggestion is closest, so far, to what I had in mind.
What suggestion is that? I don't see anything from him in the local
news spool the Google Groups archive.
> http://www.larwe.com/pdpcard.gif shows a front panel layout that is
> ALMOST final. The eight control switches are giving me trouble.
Looks fairly nice. If I were doing it, I'd probably just relax the
size requirement a little.
If those switches are momentary, you're *really* going to need a set
of LEDs for the address and test word switches. I'm speaking from
actual PDP-1 experience here; it would be difficult to operate
properly or even enter programs if you couldn't tell which way the switches
are set.
Note that the START switch on the console is an on-off-on momentary, and
there is a distinction between pressing it up and down, so if you are
using bottons you need two of them for that.
Eric
Reply by Mike Harrison●January 19, 20062006-01-19
On Thu, 19 Jan 2006 15:11:39 +0100, Rune Christensen <rune.christensen@adslhome.dk> wrote:
>Jonathan Kirwan wrote:
>> On Wed, 18 Jan 2006 02:18:01 GMT, Joerg
>> <notthisjoergsch@removethispacbell.net> wrote:
>>
>>
>>><snip>
>>>How about a very thin metallization on top of each LED and using that as
>>>a touch sensor? Thin enough to see through but conductive enough to lead
>>>to the circuit board or LED pad and generate a large enough charge hump.
>>
>>
>> Actually, my first thought was to use an LED pen and to pulse the LEDs
>> on the board used as lights, so that they could be "turned around" and
>> used as detectors, intermittently between on-pulses. Second thought
>> was to consider an unpowered pen with a bit of fluorescent material
>> taken from the inside of those compact fluorescent bulbs (cheap --
>> just break one) because the LED would energize the material and it
>> would emit a decaying pulse of return energy when brought close to a
>> pulsing LED and this extra duration could be observed.
>>
>> Hmm.... I think I'll work on the idea ... hybrid LED switches!
>
>Should be possible
>http://www.trnmag.com/Stories/2004/122904/LED_array_turned_into_touch_button_Brief_122904.html
>
>>
>> Jon
>
>/Rune
Another idea for you - use small inductors, detecting the proximity of a metallic stylus.
There are a number of methods- tuned-circuit ringdown time after 'pinging' works well (note : use
NPO or COG caps as X7Rs are too lossy. For a large number of them, change in impedance due to
eddy-current losses may be worth investigating - drive them all in parallel via resistors, and use a
diode detector to give a DC voltage that should show a measurable chnage in the presence of the
stylus.
Reply by Jonathan Kirwan●January 19, 20062006-01-19
On Thu, 19 Jan 2006 15:11:39 +0100, Rune Christensen
<rune.christensen@adslhome.dk> wrote:
>Jonathan Kirwan wrote:
>> On Wed, 18 Jan 2006 02:18:01 GMT, Joerg
>> <notthisjoergsch@removethispacbell.net> wrote:
>>
>>
>>><snip>
>>>How about a very thin metallization on top of each LED and using that as
>>>a touch sensor? Thin enough to see through but conductive enough to lead
>>>to the circuit board or LED pad and generate a large enough charge hump.
>>
>>
>> Actually, my first thought was to use an LED pen and to pulse the LEDs
>> on the board used as lights, so that they could be "turned around" and
>> used as detectors, intermittently between on-pulses. Second thought
>> was to consider an unpowered pen with a bit of fluorescent material
>> taken from the inside of those compact fluorescent bulbs (cheap --
>> just break one) because the LED would energize the material and it
>> would emit a decaying pulse of return energy when brought close to a
>> pulsing LED and this extra duration could be observed.
>>
>> Hmm.... I think I'll work on the idea ... hybrid LED switches!
>
>Should be possible
>http://www.trnmag.com/Stories/2004/122904/LED_array_turned_into_touch_button_Brief_122904.html
>
>>
>> Jon
>
>/Rune
The nice thing about using a rare earth doped ceramic (like the
fluorescent powder) is that it delays the return light response so
that it is possible to use the same LED as both emitter and detector.
But it may work well to include two dies in the same package, shielded
right, to get similar utility but with most anything brought close to
it. Anyway, it's interesting to think about.
Jon
Reply by larwe●January 19, 20062006-01-19
Fred Bartoli wrote:
> > Oh, one other thing: A citizen suggested yet another method, which is a
> > magnetic stylus and SOT23 Hall effect sensors as the "buttons". I
> > rather like this :)
> >
>
> Or reed switches?
I never saw one as small as a SOT23 Hall effect sensor.
Reply by Rune Christensen●January 19, 20062006-01-19
Jonathan Kirwan wrote:
> On Wed, 18 Jan 2006 02:18:01 GMT, Joerg
> <notthisjoergsch@removethispacbell.net> wrote:
>
>
>><snip>
>>How about a very thin metallization on top of each LED and using that as
>>a touch sensor? Thin enough to see through but conductive enough to lead
>>to the circuit board or LED pad and generate a large enough charge hump.
>
>
> Actually, my first thought was to use an LED pen and to pulse the LEDs
> on the board used as lights, so that they could be "turned around" and
> used as detectors, intermittently between on-pulses. Second thought
> was to consider an unpowered pen with a bit of fluorescent material
> taken from the inside of those compact fluorescent bulbs (cheap --
> just break one) because the LED would energize the material and it
> would emit a decaying pulse of return energy when brought close to a
> pulsing LED and this extra duration could be observed.
>
> Hmm.... I think I'll work on the idea ... hybrid LED switches!
"larwe" <zwsdotcom@gmail.com> a �crit dans le message de
news:1137644602.463004.40010@g49g2000cwa.googlegroups.com...
>
> larwe wrote:
>
> > Spehro's suggestion is closest, so far, to what I had in mind.
> > http://www.larwe.com/pdpcard.gif shows a front panel layout that is
> > ALMOST final. The eight control switches are giving me trouble.
>
> Oh, one other thing: A citizen suggested yet another method, which is a
> magnetic stylus and SOT23 Hall effect sensors as the "buttons". I
> rather like this :)
>