Paper tape supply, was Re: paper tape for GNT 4601

[Tony Duell]

> 
> David Griffith wrote:
> 
> > Sidenote: how hard would it be to make a paper tape reader and punch from
> > scratch?  The idea is to have a lightweight unit for playing with my
> > SBC6120 and perhaps Altair reissue/clone (if and when I get one).
> 
> Back in the Altair days, there was a company called Oliver Audio Engineering
> that made a small optical papertape reader for hobbyist use.  You pulled the

Incidentally, I am pretty sure the 'special' ICs in this design are 
nothing more than selected 555 timers (they're used as schmitt 
triggers).

> tape through manually.  The read strobe was generated by sensing the sprocket
> holes.  It would not be difficult to recreate this device, or something
> similar.

An optical paper tape reader should be fairly easy to make. I would 
suggest running the tape between rollers (maybe raid parts from a VCR or 
something) and take a strobe pulse from a phototransistor on the sprocket 
track, rather than using sprocket feed.

> 
> I think you'd need a machine shop and considerable skill to make a punch from
> scratch, While it would not be beyond the capabilities of those folks who build
> clocks and engines from scratch, you're best bet is to try to pick up one on

The other problem is getting a reasonable life out of it. A good model 
engineer could make a set of punch pins and a die block, but could he 
harden them and then grind them to size again? It's one thing to make a 
punch that will punch a few feet of tape, quite another to make a machine 
that can be ysed for serious work.

-tony