What is a typical keypress duration

Question

I'm doing some work on key press handing in a firmware project. I've been googling to try to find what the typical duration of a key press is, particularly the minimum for a fast typist. Surprisingly I can't find any figures for this anywhere.

Clad

You could get an estimate by just taking a reasonable typing speed (e.g. 60 wpm), average no of letters per word (say 5 + 1 space = 6), which gives key strokes per second (6), which then gives of the order of 100 ms for the key down duration. Note that debounce time is typically 10 - 20 ms, so that sets a limit on how fast even a superhuman typist could physically type. – Lauricelaurie

IIRC qemu uses a default duration of 100ms, so I think somewhere around there would be a good value. – Unregenerate

Thanks for both of those. I've done some back of the envelope figures too, which are the same. Also I can do some testing. I just wondered if anyone had authoritative/research figures – Clad

If someone may end up pressing a single button over and over (to increment or decrement something), they might be faster than a fast typist typically is. Really you need to figure the gap in timing which would differentiate legitimate inter-press times from contact bounces. If you goal is handling things on time, consider recording the keypress as distinct from processing it. – Zechariah

I assume that you cannot just use a single-pole, double-throw switch/button with a debouncing circuit, right? I believe that's what they use in life-critical applications, rather than rely on arbitrary timeouts that may or may not work. Costly, but effective... – Senior

thkala you're talking about solutions, this is helpful but it isn't really what I was getting at in the question. I'm keen to find out how long the human finger typically taps a button for. I.e. how 'quick' is a 'quick' keypress? and how much does it vary? – Clad

If I wanted to take data, I'd consider using the button to gate a 5 or 10 KHz audio oscillator feeding into a sound card (to get around the DC blocking cap) and record a file I could examine in audio software - basically, improvise a cheap digital scope with an unlimited sampling duration. – Zechariah

If you look up KLM-GOMS you should be able to find the average keypress duration for each typical typing skill, I know this isn't very specific but I hope it helps. – Pyre

Answer 1

There are some recent studies on keypress timings that have published there timings. Here are two:

http://www.cs.cmu.edu/~keystroke/ (Data gathered by Kevin Killourhy and Roy Maxion as accompaniment to "Comparing Anomaly-Detection Algorithms for Keystroke Dynamics").

Pressure-Sensitive Keystroke Dynamics (Gathered by Jeffrey D. Allen as part of his thesis).

In summary, these studies give values roughly between 50mS and 300mS.

Afterburner

Thanks for those. In summary they give 50mS-300mS ish – Clad

@Clad Thank you for pointing out the timings, the second link already died and it's nice to have the info on stackexchange itself rather than it being a website pointing to dead pages that once were interesting. – Voorhees