Show HN: Mathpad – Physical keypad for typing math symbols

That looks very cool. I wonder how hard it was to get those printed keycaps made.

Ideally you want access to everything without moving your hands off the keyboard. The DIY keyboard scene makes a lot of use of layered keymaps. It seems like the endgame for this kind of thing is not separate "keypads," but rather wider support, standardisation and adoption of multiple-layer keymaps. Half the problem is designing good maps and the other half is learning them. Sharing maps, and better software for learning/practicing the maps would help. Then you might need a few more keys to select layers. A minimum implementation might be adding a two thumb buttons below the space bar to select layers.

EDIT: inserted more text

> and what a pain in the ass it was to find the specific symbols I needed.

But that's exactly the same issue with the hardware solution - you can't use Ctrl+F to find by name and you can't see all the many symbols on the keyboard itself. You'd need a software solution to show a visual searchable "cheat sheet", and also you can map more mathy keys to an existing bigger keyboard, where entering some symbols will be way more natural, e.g., for greeks you can map most of them to different A and B latin keys instead of having both αβ on the same key. Similarly, you could do map ℤ to Z and ℕ to N, so these would be simpler to remember/input than using a dedicated keypad, so the printed symbols on the keypad aren't that useful anymore.

So, like a scaled down space-cadet keyboard. ;) Looks neat for people who write a lot of scientific papers.

With 3 modifier keys, this offers 8 potential modes. What's done with the other 2?

Why only 12 keys and 3 modifier keys? Granted, 6+ modifier keys of the SCK is probably 1 or 2 too many.

Also, I miss graphing calculators / CAS like the HP 48 where math symbols were (usually) easier-ish to access.

As an intermediate alternative between a hardware keyboard and a graphical symbol picker, I use an .XCompose file with contents that look like this:

    # GREEK
    <Multi_key> <g> <A>    : "Α"   U0391    # GREEK CAPITAL LETTER ALPHA
    <Multi_key> <g> <a>    : "α"   U03B1    # GREEK SMALL LETTER ALPHA
    <Multi_key> <g> <B>    : "Β"   U0392    # GREEK CAPITAL LETTER BETA
    <Multi_key> <g> <b>    : "β"   U03B2    # GREEK SMALL LETTER BETA
    <Multi_key> <g> <D>    : "Δ"   U0394    # GREEK CAPITAL LETTER DELTA
    <Multi_key> <g> <d>    : "δ"   U03B4    # GREEK SMALL LETTER DELTA
    <Multi_key> <g> <E>    : "Ε"   U0395    # GREEK CAPITAL LETTER EPSILON
    <Multi_key> <g> <e>    : "ε"   U03B5    # GREEK SMALL LETTER EPSILON

    ...

    # Math Symbols
    <Multi_key> <i> <n>    : "∈"   U2208 # IN
    <Multi_key> <f> <a>    : "∀"   U2200 # FOR ALL
    <Multi_key> <t> <e>    : "∃"   U2203 # THERE EXISTS
    <Multi_key> <a> <n> <d>    : "∧"   U2227 # AND
    <Multi_key> <o> <r>    : "∨"   U2228 # OR
    <Multi_key> <less> <parenleft>  : "⟨" U27E8     # MATHEMATICAL LEFT ANGLE BRACKET
    <Multi_key> <greater> <parenright>: "⟩" U27E9   # MATHEMATICAL RIGHT ANGLE BRACKET
    <Multi_key> <d> <d>    : "∂" U8706 # DEL
    <Multi_key> <n> <b>    : "∇" U8711 # NABLA

$140, lol. How about just selling the keycaps for an existing numeric pad or even small mech keyboard, and that's only if the physical keys are really needed.

The main slowdown I face as an occasional TeX user is remembering the TeX names of less frequently used symbols. For that purpose there is detexify (draw the character and find the name, doesn't work all that well) but a popup graphical menu or (if you must) a phone app would be fine.

my 2c

* the way unicode input works in qmk is pretty janky imho. this is not something you can plug into any random computer and expect to always work perfectly without doing any configuring.

* you can accomplish the same thing if you have qmk (or similar) based keyboard by throwing the symbols on another layer or whatever you prefer. for $140 you can get a whole keyboard.

the keycaps are a nice touch though

Very cool. I've long wanted something that's a bit of a cross between a calculator and a numpad; something that could be used as a calculator or just to send symbols to the computer that are easier to type on such a device.

Question: the description says it has access to all the Greek alphabet letters but only the lower case ones are shown on the keypad: do you get (e.g. ∆) by using the shift key on the regular keyboard plus δ on the Mathpad?

I think this is super cool and intend to donate because I love the love and thought you’ve put into this. With that said, did you consider using something like an Elgato Stream Deck programmable control pad?

https://www.elgato.com/us/en/p/stream-deck

How much faster is Mathpad than creating a per-document table of symbols with their Unicode numbers and/or latex values and copy/pasting until you remember the Ctrl-Shift-u nnnn sequence?

Amazing project and glad to see something like this exits. While my current setup dosnt allow for this, if that ever changes and I start taking more latex notes I will be ordering one of these.

1. Cool!

2. Why use a staggered layout? Because people are used to it? Counterpoint: the numpad is not staggered and people are easily able to use both parts of a normal keyboard)

IMO a software-based search interface is cognitively nicer. I use way too many symbols, like i𐝒.