4 Dec
2006
4 Dec
'06
3:48 p.m.
China...
On 12/3/06, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
Engineering
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 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