5 ms·

Had a question about this for while: Are movies where people communicate using knocks really accurate? I would assume to effectively use Morse code, you’ll nee

Had a question about this for while: Are movies where people communicate using knocks really accurate? I would assume to effectively use Morse code, you’ll need a way to convey short silence, long silence, short beep, and long beep. Knocking misses the long beep.

kqr 9y ago
This has been a major annoyance for me my entire life. Of course, you cannot possibly produce a long knock, any more than shooting someone slowly is a vengeful way of killing. What I guess you can do is vary the acoustics of your knocks (think knuckles vs palm) but this will require the recieving party to do much more processing when decoding.
- whatshisface 9y ago
  Knock whenever switching from beep-off to beep-on. The end of letters will be difficult to disambiguate but essentially unambiguous, because short pause + long pause (dot at end of letter) is distinct from medium pause + long pause (dash at end of letter), and they're both distinct from short pause (dot inside letter) and medium pause (dash inside letter).
- bigKnockrs 9y ago
  I think that's a little bit pedantic. Complaining loudly about how the knocks technically aren't, themselves, longer or shorter is a digression from the reality that any sane human can detect and recognize consistent patterns in a series of knocks on a door, or beats on a drum. shave and-a hair cut... two! bits! [0] match in-the gas tank... boom! boom! [1] –··–· ·· Everybody recognizes that knock pattern, whether they know the trivia behind its origins or not. The singular instrument leaves the interpretation to the pattern of the beats alone. Meanwhile, a rimshot, involving two drum hits and a cymbal crash offers two channels of interpretation. ba-dum tiss! [2] The rhythm and the sound could each carry separate messages, which means the carrier signal would have to be agreed upon, before sending the message. Is the cymbal crash the best carrier for the dashes, or is the rest note in between the drum hits and the cymbal crash actually the pause that signals the dash? [0] https://en.wikipedia.org/wiki/Shave_and_a_Haircut https://en.wikipedia.org/wiki/Shave_and_a_Haircut [1] https://www.youtube.com/watch?v=i5KBVCoKYt0 https://www.youtube.com/watch?v=i5KBVCoKYt0 [2] https://en.wikipedia.org/wiki/Rimshot https://en.wikipedia.org/wiki/Rimshot
detaro 9y ago
You can do longer pauses between knocks for dashes, and then even longer ones for the actual pauses. KnockKnockKnock vs Knock. Knock. Knock. But there also are alternative codes for knocks, e.g. doing two groups of 1-5 knocks per letter (=25 letters encoded)
hiccuphippo 9y ago
Two quick knocks can mean a dash. Also, isthereaproblemwithnospaceswhentryingtosaveyourlife?
- saghm 9y ago
  > Also, isthereaproblemwithnospaceswhentryingtosaveyourlife? I think that's a bit of an oversimplification since there's no ambiguity in text about where one letter ends and the other begins. The issue isn't spacing between words, it's spacing between _letters_
  - thaumasiotes 9y ago
    GP comment stated that four symbols (dot, dash, short pause, long pause) were required for Morse code. This is wrong; Morse code involves three symbols, dot, dash, and pause. I assume your parent comment interpreted the spurious requirement for "long pause" as an assumption that for communication to take place, you'd have to have a robust distinction between letter spacing and word spacing.
lawl 9y ago
I don't know if they're accurate, but there is Tap code for this exact reason.[0] Not that I have known this before, but people talk about it in TFAs comments as 5x5. [0] https://en.wikipedia.org/wiki/Tap_code https://en.wikipedia.org/wiki/Tap_code
jdietrich 9y ago
American POWs in Vietnam reportedly used a tap code based on a 5x5 matrix of letters. Each letter is encoded as the indices within that matrix, so "tap, tap" is A, "tap tap, tap" is B and so on, through to "tap tap tap tap tap, tap tap tap tap tap" for Z. The letters C and K share the index [3, 1]. https://en.wikipedia.org/wiki/Tap_code https://en.wikipedia.org/wiki/Tap_code

kqr 9y ago

This has been a major annoyance for me my entire life. Of course, you cannot possibly produce a long knock, any more than shooting someone slowly is a vengeful way of killing. What I guess you can do is vary the acoustics of your knocks (think knuckles vs palm) but this will require the recieving party to do much more processing when decoding.

whatshisface 9y ago
Knock whenever switching from beep-off to beep-on. The end of letters will be difficult to disambiguate but essentially unambiguous, because short pause + long pause (dot at end of letter) is distinct from medium pause + long pause (dash at end of letter), and they're both distinct from short pause (dot inside letter) and medium pause (dash inside letter).
bigKnockrs 9y ago
I think that's a little bit pedantic. Complaining loudly about how the knocks technically aren't, themselves, longer or shorter is a digression from the reality that any sane human can detect and recognize consistent patterns in a series of knocks on a door, or beats on a drum. shave and-a hair cut... two! bits! [0] match in-the gas tank... boom! boom! [1] –··–· ·· Everybody recognizes that knock pattern, whether they know the trivia behind its origins or not. The singular instrument leaves the interpretation to the pattern of the beats alone. Meanwhile, a rimshot, involving two drum hits and a cymbal crash offers two channels of interpretation. ba-dum tiss! [2] The rhythm and the sound could each carry separate messages, which means the carrier signal would have to be agreed upon, before sending the message. Is the cymbal crash the best carrier for the dashes, or is the rest note in between the drum hits and the cymbal crash actually the pause that signals the dash? [0] https://en.wikipedia.org/wiki/Shave_and_a_Haircut https://en.wikipedia.org/wiki/Shave_and_a_Haircut [1] https://www.youtube.com/watch?v=i5KBVCoKYt0 https://www.youtube.com/watch?v=i5KBVCoKYt0 [2] https://en.wikipedia.org/wiki/Rimshot https://en.wikipedia.org/wiki/Rimshot

detaro 9y ago

You can do longer pauses between knocks for dashes, and then even longer ones for the actual pauses. KnockKnockKnock vs Knock. Knock. Knock. But there also are alternative codes for knocks, e.g. doing two groups of 1-5 knocks per letter (=25 letters encoded)

hiccuphippo 9y ago

Two quick knocks can mean a dash. Also, isthereaproblemwithnospaceswhentryingtosaveyourlife?

saghm 9y ago
> Also, isthereaproblemwithnospaceswhentryingtosaveyourlife? I think that's a bit of an oversimplification since there's no ambiguity in text about where one letter ends and the other begins. The issue isn't spacing between words, it's spacing between _letters_
- thaumasiotes 9y ago
  GP comment stated that four symbols (dot, dash, short pause, long pause) were required for Morse code. This is wrong; Morse code involves three symbols, dot, dash, and pause. I assume your parent comment interpreted the spurious requirement for "long pause" as an assumption that for communication to take place, you'd have to have a robust distinction between letter spacing and word spacing.

lawl 9y ago

I don't know if they're accurate, but there is Tap code for this exact reason.[0] Not that I have known this before, but people talk about it in TFAs comments as 5x5. [0] https://en.wikipedia.org/wiki/Tap_code https://en.wikipedia.org/wiki/Tap_code

jdietrich 9y ago

American POWs in Vietnam reportedly used a tap code based on a 5x5 matrix of letters. Each letter is encoded as the indices within that matrix, so "tap, tap" is A, "tap tap, tap" is B and so on, through to "tap tap tap tap tap, tap tap tap tap tap" for Z. The letters C and K share the index [3, 1]. https://en.wikipedia.org/wiki/Tap_code https://en.wikipedia.org/wiki/Tap_code