23 Nov
2007
23 Nov
'07
6:05 p.m.
From: rtellason at verizon.net
I notice that even those guys that are building relay computers "cheat" and
use a single small solid-state chip for RAM. :-)
Hi
I've been thinking about how one could make a reasonable
memory, using small reed relays. If one puts a magnet close
to one end, it will cause the reed to close. Move it back
some and it will hold until the field is too weak.
If one set the magnet someplace in the middle of this
band, one could use the direction of current through the
coil to set and reset the contacts.
One could create an array of these for the memory. Placing
small magnets in opposite directions for adjacent bits would
keep from building too high a field buildup, in the array.
I was thinking that one could use small round magnets
glued to the end of a threaded rod. This could then be adjusted
to optimize the memory.
Now all I need is a pile of reed relays.
Dwight
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26 Nov
26 Nov
11:32 a.m.
On Friday 23 November 2007 19:05, dwight elvey wrote:
Dunno if they still sell them or not, but Radio Shack used to sell a pack of
20 reed switches for only a couple of bucks...
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin
From:
rtellason at verizon.net
I notice that even those guys that are building relay computers "cheat"
and use a single small solid-state chip for RAM. :-)
Hi
I've been thinking about how one could make a reasonable
memory, using small reed relays. If one puts a magnet close
to one end, it will cause the reed to close. Move it back
some and it will hold until the field is too weak.
If one set the magnet someplace in the middle of this
band, one could use the direction of current through the
coil to set and reset the contacts.
One could create an array of these for the memory. Placing
small magnets in opposite directions for adjacent bits would
keep from building too high a field buildup, in the array.
I was thinking that one could use small round magnets
glued to the end of a threaded rod. This could then be adjusted
to optimize the memory.
Now all I need is a pile of reed relays.
Dwight 
12:15 p.m.
Roy J. Tellason wrote:
On Friday 23 November 2007 19:05, dwight elvey wrote:
>> From: rtellason at verizon.net
>>
>> I notice that even those guys that are building relay computers "cheat"
>> and use a single small solid-state chip for RAM. :-)
>>
> Hi
> I've been thinking about how one could make a reasonable
> memory, using small reed relays. If one puts a magnet close
> to one end, it will cause the reed to close. Move it back
> some and it will hold until the field is too weak.
>
..
Dunno if they still sell them or not, but Radio Shack used to sell a pack of
20 reed switches for only a couple of bucks...
Hmm... Wonder if it's possible to build a relay without a spring on the
switch. That is, you have to send current with one polarity to set the
switch to a 1 and reverse polarity to set a zero - sort of what core
memory does with rings... I suppose this could instead be done by
attaching a magnet to the switch, or using magnet as the thing inside
the switch body, or better yet maybe a relay with a ball with a set of
contacts as the switch and two magnets, one on each opposite side...
you'd energize one coil for a "1" and the other for a "0"
Hmm, could even be done with a solenoid and use the mechanical part of
it to touch a wire for output. :-) Wouldn't really be a relay, but
pretty close.
12:26 p.m.
Date: Mon, 26 Nov 2007 13:15:02 -0500> From: ray at
arachelian.com> To: > Subject: Re: *updating* 8088's> > Roy J. Tellason
wrote:> > On Friday 23 November 2007 19:05, dwight elvey wrote:> > >
>>> From: rtellason at verizon.net> >>>> >>> I notice
that even those guys that are building relay computers "cheat"> >>>
and use a single small solid-state chip for RAM. :-)> >>> > >> Hi>
>> I've been thinking about how one could make a reasonable> >> memory,
using small reed relays. If one puts a magnet close> >> to one end, it will cause
the reed to close. Move it back> >> some and it will hold until the field is too
weak.> >> > ..> >> > Dunno if they still sell them or not, but
Radio Shack used to sell a pack of > > 20 reed switches for only a couple of
bucks...> >> > > > Hmm... Wonder if it's possible to build a relay
without a spring on the > switch. That is, you have to send current with one polarity
to set the > switch to a 1 and reverse polarity to set a zero - sort of what core >
memory does with rings... I suppose this could instead be done by > attaching a magnet
to the switch, or using magnet as the thing inside > the switch body, or better yet
maybe a relay with a ball with a set of > contacts as the switch and two magnets, one
on each opposite side... > you'd energize one coil for a "1" and the
other for a "0" > > Hmm, could even be done with a solenoid and use the
mechanical part of > it to touch a wire for output. :-) Wouldn't really be a relay,
but > pretty close.> >
Teledyne makes a 'non volitale' relay. its tradename is Maglatch.
Randy
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1:33 p.m.
On Monday 26 November 2007 13:26, Randy Dawson wrote:
> Date: Mon, 26 Nov 2007 13:15:02 -0500> From:
ray at arachelian.com> To: >
> Subject: Re: *updating* 8088's> > Roy J. Tellason wrote:> > On
Friday 23
> November 2007 19:05, dwight elvey wrote:> > > >>> From:
> rtellason at verizon.net> >>>> >>> I notice that even those
guys that are
> building relay computers "cheat"> >>> and use a single small
solid-state
> chip for RAM. :-)> >>> > >> Hi> >> I've been
thinking about how one could
> make a reasonable> >> memory, using small reed relays. If one puts a
> magnet close> >> to one end, it will cause the reed to close. Move it
> back> >> some and it will hold until the field is too weak.> >>
> ..> >>
> > Dunno if they still sell them or not, but Radio Shack used to sell a
> pack of > > 20 reed switches for only a couple of bucks...> >> >
> >
> Hmm... Wonder if it's possible to build a relay without a spring on the >
> switch. That is, you have to send current with one polarity to set the >
> switch to a 1 and reverse polarity to set a zero - sort of what core >
> memory does with rings... I suppose this could instead be done by >
> attaching a magnet to the switch, or using magnet as the thing inside >
> the switch body, or better yet maybe a relay with a ball with a set of >
> contacts as the switch and two magnets, one on each opposite side... >
> you'd energize one coil for a "1" and the other for a "0"
> > Hmm, could
> even be done with a solenoid and use the mechanical part of > it to touch
> a wire for output. :-) Wouldn't really be a relay, but > pretty close.>
>
Ack! :-)
Teledyne makes a 'non volitale' relay. its
tradename is Maglatch.
They did some pretty impressive stuff. I had some one time that were in an
8-leaded TO-5 Can, DPDT with a transistor driver and diode in there with it.
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin
11:56 p.m.
On Nov 26, 2007 10:26 AM, Randy Dawson <rdawson16 at hotmail.com> wrote:
Teledyne makes a 'non volitale' relay. its
tradename is Maglatch.
Lots of manufacturers make latching relays (or at least used to. I
haven't had need to use one in over 10 years). We used to use them
for power switching in most of our designs. At one time we had to
switch away from teledyne relays because they could end up in an
indeterminate and worse uncommandable state if exposed random
vibration levels normally associated with the launch vehicles we were
using. I believe they eventually fixed that issue, but it caused us a
lot of problems in trying to find a replacement in a similar form
factor.
"latching relays" only brings up 53000 hits on google, so I assume
they are still fairly common.
Eric
27 Nov
27 Nov
2:36 a.m.
On 26 Nov 2007 at 21:56, Eric J Korpela wrote:
On Nov 26, 2007 10:26 AM, Randy Dawson <rdawson16
at hotmail.com> wrote:
> Teledyne makes a 'non volitale' relay. its tradename is Maglatch.
I recall a latching relay in my Lionel toy train engine that I had
when I was a mere tyke. It used a rachet-and-pawl arrangement to
reverse the direction of the motor rotation. Only a pulse was
necessary to change direction.
I've actually seen stepping switches used as memory in primitive
computers. IIRC, the position is advanced when a step pulse is
received and reset when the reset coil is pulsed. Otherwise, the
switch retains its setting if power is removed. Certainly one could
be used as a memory element as well as a mux or demux.
Cheers,
Chuck
26 Nov
26 Nov
5:39 p.m.
Hmm... Wonder if it's possible to build a relay
without a spring on the
switch. That is, you have to send current with one polarity to set the
switch to a 1 and reverse polarity to set a zero - sort of what core
memory does with rings... I suppose this could instead be done by
attaching a magnet to the switch, or using magnet as the thing inside
the switch body, or better yet maybe a relay with a ball with a set of
contacts as the switch and two magnets, one on each opposite side...
you'd energize one coil for a "1" and the other for a "0"
Absolutely, Such devices exist, and are normally magnetically-latched.
There are types with one coil (as you say, one polarity to 'set', the
other to 'reset') and ones with 2 coils which often you can either use as
spearate set and reset coils, or wire them togetner and use them as a
single polarity-dependant coil.
They're often used where the power required to hold a normal relay
energised would be a problem. One classic-computer applciations that I've
come across is that the cassette control relays in the cassette
interface/printer for Sharp pocket computers (PC1500, PC1350, etc) are
of this type.
I think that polaristed telegraph relays ('Carpenter relays' over here)
were designed to be stable in each state. Sort-of on-topic too...
Incidentally, remember those little 4-pen plotters that Radio Shack used
in the CGP115, Commoodore used in the 1520, etc, etc, etc. The pen
up/down solenoid in those is magnetically-latched. A pulse of one
polarity puts the pane on to the paper, a pulse of the other polarity
lifts it off again.
-tony
27 Nov
27 Nov
11:05 a.m.
New subject: Small 4-pen plotters was Re: *updating* 8088's
On Monday 26 November 2007 18:39, Tony Duell wrote:
Incidentally, remember those little 4-pen plotters
that Radio Shack used
in the CGP115, Commoodore used in the 1520, etc, etc, etc. The pen
up/down solenoid in those is magnetically-latched. A pulse of one
polarity puts the pane on to the paper, a pulse of the other polarity
lifts it off again.
Speaking of those, I have somewhere one of those that is branded IBM. It's
missing a power supply, and the connector where said supply goes in is a bit
odd, not something I recall ever seeing anywhere else. Anybody know where I
might pursue some info on that thing? I'm thinking that at worst I can
probably hard-wire something into it...
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin
7:02 a.m.
On 2007-11-26 18:32, Roy J. Tellason wrote:
There's Chinese guys on eBay selling packs of fifty print relays for under
ten dollars plus shipping. They're only single throw, so a bunch would be
needed for some functions, but at those prices... An 8x8 RAM card would take
about 150 relays (eight latches per byte, eight enablers, one hold, one
select, and a couple extra for three bit address decoding). But really, how
much RAM would you need on a relay computer? Half the fun is in building a
somewhat limited machine to see what you can do, right? Plus, replace some
of the relays with switches, and you have ROM to hold a program.
Hmm... Time to fire up EagleCAD! :-)
,xtG
.tsooJ
--
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cd $HOME; unzip; touch; strip; finger
mount; gasp; yes; uptime; umount
sleep
--
Joost van de Griek
<http://www.jvdg.net/>
I've been
thinking about how one could make a reasonable memory, using small
reed relays. If one puts a magnet close to one end, it will cause the reed to
close. Move it back some and it will hold until the field is too weak.
If one set the magnet someplace in the middle of this band, one could use the
direction of current through the coil to set and reset the contacts.
One could create an array of these for the memory. Placing small magnets in
opposite directions for adjacent bits would keep from building too high a
field buildup, in the array.
I was thinking that one could use small round magnets glued to the end of a
threaded rod. This could then be adjusted to optimize the memory.
Now all I need is a pile of reed relays.
Dunno if they still sell them or not, but Radio Shack used to sell a pack of
20 reed switches for only a couple of bucks...
6547
days inactive
6550
days old
9 comments
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participants (8)
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ard＠p850ug1.demon.co.uk -
cclist＠sydex.com -
dkelvey＠hotmail.com -
jvdg＠sparcpark.net -
korpela＠ssl.berkeley.edu -
ray＠arachelian.com -
rdawson16＠hotmail.com -
rtellason＠verizon.net