[Upcycle It] Hermes 3000 - Post #2

RE: [Upcycle It] Hermes 3000 - Post #2

Workshopshed — Sun, 09 Apr 2017 19:58:55 GMT

The MCU does seem to have good capability, nice to see you've got it working.

RE: [Upcycle It] Hermes 3000 - Post #2

DAB — Sun, 09 Apr 2017 17:10:36 GMT

Interesting approach.

I think I would have used a webcam and do character recognition on the key face.

DAB

RE: [Upcycle It] Hermes 3000 - Post #2

mcb1 — Sun, 09 Apr 2017 00:18:10 GMT

(I don't know what they are actually called in typewriter lingo):

They are called Type according to this.

http://site.xavier.edu/polt/typewriters/Hermes3000.pdf

it came from here

Typewriter Manuals

It looks like you have solution that will work.

Personally I always prefer to ground things.

It means that you can't short the 5v to ground.

The logic is the other way up, so that the pin goes high (via a suitable resistor) when the type arm lifts stops grounding out that input.

Mark

RE: [Upcycle It] Hermes 3000 - Post #2

jc2048 — Sat, 08 Apr 2017 23:02:58 GMT

I think it's because you clock the shift register and then read it.

The QH output has the H input value immediately after the parallel load. You don't need to clock the shift register to get it into place. Clocking the shift register then moves the G input stored value to the QH, and so on.

Try with the clock toggle after the read in your code.

If you need to save IO pins later, keep in mind that you can feed the output data from one shift register to another, so you could arrange the whole thing as three 16-bit shift registers, or two 24-bit shift registers, or even one 48-bit shift register.