building my own relay computer

[ben]

On 2/14/2015 1:14 AM, ben wrote:
> On 2/14/2015 1:05 AM, Dave G4UGM wrote:
>>
>>
>>> -----Original Message-----
>>> From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Dale H.
>>> Cook
>>> Sent: 14 February 2015 03:41
>>> To: cctalk at classiccmp.org
>>> Subject: Re: building my own relay computer
>>>
>>> At 08:14 PM 2/13/2015, Ben wrote:
>>>
>>> The alu has never relay been a problem with relays, but what about main
>>> storage? Punched tape (paper/film/card) is no longer with us for I/O.
>>>
>>
>> Punched tape is about. Check out the "green keys" list, 5-level stuff
>> comes
>> up from time to time, generally at low cost. There is some ex-CNC
>> items on
>> E-Bay at present but for silly prices. Whilst I haven't seen any on E-Bay
>> there were three Documation readers advertised on the Vintage Computer
>> forums.
>>
>>
>>> Fifty years ago I got around that by building my own card reader (very
>> slow)
>>> for input and hand-punching Hollerith cards with a hole punch. That was
>>> some years before I got access to an IBM card punch in high school.
>>> Output
>>> was a set of electro-mechanical counters, and they were a real pain to
>>> implement.
>>>
>>
>> Many folks have implemented photo electric tape readers, but these
>> tend to
>> be clocked off the small feed holes. I guess it wouldn't be too hard to
>> build a photo electric reader that has a 3-d printed feed wheel that was
>> driven by a stepper motor. In fact I am pretty sure you could even use a
>> coil and ratchet arrangement, like this one here:-
>>
>> http://grabcad.com/library/cam-operated-ratchet-pawl-1
>>
>> but operated buy a coil and magnet rather than a rotating cam. Some
>> one has
>> actually made a complete but operated mechanical punch card computer..
>>
>> http://observationdeck.io9.com/a-3-d-printed-hand-cranked-punch-card-compute
>>
>> r-1481921919
>>
>> so I don't think its hard. Getting things 3-D printed isn't hard, in fact
>> most FabLabs will have one and things can be printed for the cost of
>> materials. Also Hack Space...
>>
>>   I think it's the punch that's harder. You would need to harden the
>> punch
>> pins, and the would need to have a very exact fit. I guess a CNC router
>> could be used to make these...
>>
>
> I think that needs real machine work. Strange what you could do 100
> years ago you can not do today.
> Computer controlled stuff is good for may things but not that.
error: many things
> Ben.
>
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>
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