Comments on: A retro twitter wall (twypper)

By: Alex

Alex — Thu, 17 Dec 2009 22:46:11 +0000

Hi Michael,
your analysis is absolutely correct.
I chose the shift register mostly because I had no multiplexers at hand
You can even drop the shift register if you have enough pins on your controller.
It’s more or less a matter of taste, which route you go.
Cheers,
Alex

By: Michael Gold

Michael Gold — Thu, 17 Dec 2009 18:17:31 +0000

Can you compare the shift-register approach you took on this project with the 4051-multiplexer approach taken by oomlaut?

I’m a bit of a newbie at this but here is what I am able to observe: The 4051-multiplexer approach doesn’t seem to be concerned at all with sensing the scanning. However, that comes at a cost of the increased part count of 2x 4051’s to connect the full keyoard matrix (vs the 1 shift register you use here).

Conversely, the shift register reduces the part count, but that comes with the requirement to measure the scanning frequency of the keyboard encoder in advance such that the timing of the out-line lows can be captured in the software. The wiring of the full matrix might still need to be done in order to measure the scanning interval on the out-lines, even though only one of the out lines is used in the final implementation.

Curious to know your thoughts…

Michael

By: bausteln > Heute: Bausteln, Lesen, Fernsehen

bausteln > Heute: Bausteln, Lesen, Fernsehen — Wed, 02 Dec 2009 14:32:25 +0000

[...] sind wir nicht die ersten – erst vor einigen Tagen wurde mit dem twypper wieder ein solches Projekt veröffentlicht. Leider hat es zum atoms&bits-Festival im [...]

By: Twypper – A retro typewriter that prints your tweets

Twypper – A retro typewriter that prints your tweets — Mon, 30 Nov 2009 14:53:08 +0000

[...] craziestgadgets tinkerlog Posted by ketyungon Mon, Nov 30th, 09at 10:52 amvar addthis_pub="49fda67f77a9e9df"; [...]

By: Commodore SQ1000 twitter wall: the twypper - Hack a Day

Commodore SQ1000 twitter wall: the twypper - Hack a Day — Tue, 24 Nov 2009 19:07:46 +0000

[...] Before we begin, let us soothe those first dreaded thoughts. No, the commodore was not destroyed in the process. They can simply clip the 16 wires they added to interface the keyboard and be back to stock. Breathe a sigh of relief, and enjoy the twypper, a twitter wall made from a commodore SQ1000. [...]

By: Det här kan du göra med en skrivmaskin | Törnebohms Hotspot

Det här kan du göra med en skrivmaskin | Törnebohms Hotspot — Tue, 24 Nov 2009 05:49:28 +0000

[...] Tinkerlog [...]

By: A Twittering Typewriter (Twypper) | CraziestGadgets.com

A Twittering Typewriter (Twypper) | CraziestGadgets.com — Mon, 23 Nov 2009 17:52:13 +0000

[...] old and new into one neat hack, the folks at Tinkerlog took and old Commodore SQ 1000 electric typewriter and hooked it up via Arduino with an Ethernet [...]

By: gerd

gerd — Sun, 22 Nov 2009 17:50:10 +0000

Very nice. Back in the Eightees, I used a ZX81 to connect it to a mil teletypewriter in a similar way. And to a commercial 120-char-wide Centronics Matrixprinter with a 230V/110V transformer, all operating in my living room. Noisy. Very much looked like your breadboard.

Gerd