Minimal Key Calculator
03-13-2015, 08:17 AM
Post: #1
 Gerald H Senior Member Posts: 1,620 Joined: May 2014
Minimal Key Calculator
In another thread the question of unnecessary functions & redundant keys is raised:

What could be the least number of keys needed to reproduce all the functions of, say, the HP 35S keyboard?

If you were happy with a purely binary calculator, only two number keys would be required - but probably you would want to keep decimal input, so let's say you stay decimal.
03-13-2015, 08:32 AM (This post was last modified: 03-13-2015 08:35 AM by Didier Lachieze.)
Post: #2
 Didier Lachieze Senior Member Posts: 1,602 Joined: Dec 2013
RE: Minimal Key Calculator
(03-13-2015 08:17 AM)Gerald H Wrote:  In another thread the question of unnecessary functions & redundant keys is raised:

What could be the least number of keys needed to reproduce all the functions of, say, the HP 35S keyboard?

If you were happy with a purely binary calculator, only two number keys would be required - but probably you would want to keep decimal input, so let's say you stay decimal.

With 16 keys you can have the complete HP 41CX function set:

03-13-2015, 08:51 AM (This post was last modified: 03-13-2015 08:56 AM by Paul Dale.)
Post: #3
 Paul Dale Senior Member Posts: 1,815 Joined: Dec 2013
RE: Minimal Key Calculator
Is chording permitted? This greatly multiplies the number of keyboard positions. For a two chord keyboard with n keys, you get n+nC2 = ½(n²+n). A three chord keyboard gives n+nC2+nC3 = ⅙(n³+5n). And so forth. The effect is multiplied again if the order the chord keys is considered.

As for minimal, one key is clearly sufficient -- input using Morse code or similar.

- Pauli
03-13-2015, 08:51 AM
Post: #4
 PANAMATIK Senior Member Posts: 1,028 Joined: Oct 2014
RE: Minimal Key Calculator
(03-13-2015 08:17 AM)Gerald H Wrote:  What could be the least number of keys needed to reproduce all the functions of, say, the HP 35S keyboard?

The ENTER key.

If you press ENTER repeatedly with special timing gaps you can enter 2^6 different codes with a maximum of 4 key presses each. This is more than sufficient for the HP35S 43 keys. The first ENTER is the start bit followed by 6 bits key code. With 2 baud, that is a maximum one keystroke per second, you can enter 100 program steps in approximately 400 seconds.

Even less keys needed by speech entry.

Bernhard

That's one small step for a man - one giant leap for mankind.
03-13-2015, 09:50 AM (This post was last modified: 03-13-2015 09:55 AM by Gerald H.)
Post: #5
 Gerald H Senior Member Posts: 1,620 Joined: May 2014
RE: Minimal Key Calculator
Edit: Clearly I don't have imagination enough & now rescind my decision below to one in favour of PANAMATIK with zero keys. I should have added the proviso of entry only by key.

(03-13-2015 08:51 AM)Paul Dale Wrote:  Is chording permitted? This greatly multiplies the number of keyboard positions. For a two chord keyboard with n keys, you get n+nC2 = ½(n²+n). A three chord keyboard gives n+nC2+nC3 = ⅙(n³+5n). And so forth. The effect is multiplied again if the order the chord keys is considered.

As for minimal, one key is clearly sufficient -- input using Morse code or similar.

- Pauli

OK, definitely winner of the competition.

My specifications were vague (not deliberately, as I guess most people are mind-readers & have the same background thoughts as me) & I should have added the proviso of not inducing repetitive strain injury after 60 mins usage.
03-13-2015, 10:20 AM (This post was last modified: 03-13-2015 11:13 AM by BartDB.)
Post: #6
 BartDB Member Posts: 162 Joined: Feb 2015
RE: Minimal Key Calculator
(03-13-2015 08:17 AM)Gerald H Wrote:  In another thread the question of unnecessary functions & redundant keys is raised:

What could be the least number of keys needed to reproduce all the functions of, say, the HP 35S keyboard?

If you were happy with a purely binary calculator, only two number keys would be required - but probably you would want to keep decimal input, so let's say you stay decimal.

Not the least number of keys, but what I'd be comfortable using without too many shifts & menu's. Small form factor with 23 keys:

http://pickyb.blogspot.co.uk/2014/05/pro...kcalc.html

Best regards.

Attached File(s) Thumbnail(s)

03-13-2015, 10:32 AM
Post: #7
 Massimo Gnerucci Senior Member Posts: 2,641 Joined: Dec 2013
RE: Minimal Key Calculator
(03-13-2015 08:32 AM)Didier Lachieze Wrote:  With 16 keys you can have the complete HP 41CX function set:

And operators are on the left, of course... ;)

Greetings,
Massimo

-+×÷ ↔ left is right and right is wrong
03-13-2015, 10:41 AM
Post: #8
 Didier Lachieze Senior Member Posts: 1,602 Joined: Dec 2013
RE: Minimal Key Calculator
A calculator without any key: MyScript Calculator (available for IOS & Android).

03-13-2015, 11:14 AM
Post: #9
 Paul Dale Senior Member Posts: 1,815 Joined: Dec 2013
RE: Minimal Key Calculator
The way the question is posed "least number of keys" would imply a minimum of two keys and disallow none or one. In this case two keys are clearly enough -- the morse code key and a power button

- Pauli
03-13-2015, 11:26 AM
Post: #10
 PANAMATIK Senior Member Posts: 1,028 Joined: Oct 2014
RE: Minimal Key Calculator
(03-13-2015 11:14 AM)Paul Dale Wrote:  The way the question is posed "least number of keys" would imply a minimum of two keys and disallow none or one. In this case two keys are clearly enough -- the morse code key and a power button

- Pauli

Don't be overhasty. Perhaps some mathematician will show a solution with a negative number of keys. Might be useful for entering imaginary numbers. Is minus infinity keys less than zero keys?

Bernhard

That's one small step for a man - one giant leap for mankind.
03-13-2015, 11:57 AM
Post: #11
 Gerald H Senior Member Posts: 1,620 Joined: May 2014
RE: Minimal Key Calculator
(03-13-2015 11:26 AM)PANAMATIK Wrote:
(03-13-2015 11:14 AM)Paul Dale Wrote:  The way the question is posed "least number of keys" would imply a minimum of two keys and disallow none or one. In this case two keys are clearly enough -- the morse code key and a power button

- Pauli

Don't be overhasty. Perhaps some mathematician will show a solution with a negative number of keys. Might be useful for entering imaginary numbers. Is minus infinity keys less than zero keys?

Bernhard

No, no, this is stretching things too far.

As clarification, in this & any other issues I may raise, answers must be limited to real rationals, or if you like Diophantine.
03-13-2015, 12:07 PM
Post: #12
 Gerald H Senior Member Posts: 1,620 Joined: May 2014
RE: Minimal Key Calculator
(03-13-2015 11:26 AM)PANAMATIK Wrote:
(03-13-2015 11:14 AM)Paul Dale Wrote:  The way the question is posed "least number of keys" would imply a minimum of two keys and disallow none or one. In this case two keys are clearly enough -- the morse code key and a power button

- Pauli

Don't be overhasty. Perhaps some mathematician will show a solution with a negative number of keys. Might be useful for entering imaginary numbers. Is minus infinity keys less than zero keys?

Bernhard

Hoist with my own petard, the underlined "s"!

It's an unfortunate idiosyncracy of colloquial English that grammatical number has to be specified.

Fortunately Japanese does not have this obsession with number - I'll try to nipponize my English in this respect in future.
03-13-2015, 12:13 PM (This post was last modified: 03-13-2015 12:13 PM by Gerald H.)
Post: #13
 Gerald H Senior Member Posts: 1,620 Joined: May 2014
RE: Minimal Key Calculator
(03-13-2015 11:14 AM)Paul Dale Wrote:  The way the question is posed "least number of keys" would imply a minimum of two keys and disallow none or one. In this case two keys are clearly enough -- the morse code key and a power button

- Pauli

No, Paul, I must criticize your use of English.

While one is clearly disallowed, the expression is correctly "zero keys" or "no keys"!
03-13-2015, 05:59 PM
Post: #14
 Thomas Radtke Senior Member Posts: 848 Joined: Dec 2013
RE: Minimal Key Calculator
(03-13-2015 12:13 PM)Gerald H Wrote:  While one is clearly disallowed, the expression is correctly "zero keys" or "no keys"!
But Paul wrote 'none', which is correctly none (not one) key .
03-13-2015, 06:17 PM (This post was last modified: 03-13-2015 06:17 PM by Gerald H.)
Post: #15
 Gerald H Senior Member Posts: 1,620 Joined: May 2014
RE: Minimal Key Calculator
(03-13-2015 12:13 PM)Gerald H Wrote:  While one is clearly disallowed, the expression is correctly "zero keys" or "no keys"!
But Paul wrote 'none', which is correctly none (not one) key .

Except "none key" is wrong & "the least number of keys" would not exclude zero.

03-13-2015, 09:14 PM
Post: #16
 rprosperi Super Moderator Posts: 5,980 Joined: Dec 2013
RE: Minimal Key Calculator
(03-13-2015 08:32 AM)Didier Lachieze Wrote:
(03-13-2015 08:17 AM)Gerald H Wrote:  In another thread the question of unnecessary functions & redundant keys is raised:

What could be the least number of keys needed to reproduce all the functions of, say, the HP 35S keyboard?

If you were happy with a purely binary calculator, only two number keys would be required - but probably you would want to keep decimal input, so let's say you stay decimal.

With 16 keys you can have the complete HP 41CX function set:

Didier - could you please post a larger, hi-res scan of that, or point out where it may be found if already online somewhere. It looks mightly interesting, even if all it does is answer the topic of this thread, however I'd guess it does more than that. Thanks.

--Bob Prosperi
03-13-2015, 09:31 PM
Post: #17
 Didier Lachieze Senior Member Posts: 1,602 Joined: Dec 2013
RE: Minimal Key Calculator
There was one overlay for sale on ebay.de some weeks ago.
Here is a picture from this auction: Laitram XQ2.
You can also find the Laitram manual on TAS.
03-13-2015, 09:34 PM
Post: #18
 Massimo Gnerucci Senior Member Posts: 2,641 Joined: Dec 2013
RE: Minimal Key Calculator
(03-13-2015 09:14 PM)rprosperi Wrote:
(03-13-2015 08:32 AM)Didier Lachieze Wrote:  With 16 keys you can have the complete HP 41CX function set:

Didier - could you please post a larger, hi-res scan of that, or point out where it may be found if already online somewhere. It looks mightly interesting, even if all it does is answer the topic of this thread, however I'd guess it does more than that. Thanks.

Greetings,
Massimo

-+×÷ ↔ left is right and right is wrong
03-13-2015, 09:36 PM (This post was last modified: 03-13-2015 09:49 PM by Massimo Gnerucci.)
Post: #19
 Massimo Gnerucci Senior Member Posts: 2,641 Joined: Dec 2013
RE: Minimal Key Calculator

Greetings,
Massimo

-+×÷ ↔ left is right and right is wrong
03-13-2015, 10:09 PM
Post: #20
 TASP Senior Member Posts: 401 Joined: Mar 2015
RE: Minimal Key Calculator
LOL, how finely could a knob be turned connected to a rheostat, and an appropriate digital VOM circuit attached, and each unique resistance reading would correspond to a digit or function ??

2speed HP41CX,int2XMEM+ZEN, HPIL+DEVEL, HPIL+X/IO, I/R, 82143, 82163, 82162 -25,35,45,55,65,67,70,80
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