Weird HP keypad with 32 keys

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31 Jan 2020, 03:35

I found this bizarre keypad sort of thing, maybe a macro pad of sorts. It's made by HP, and has 32 keys in an ortholinear cross shape. The switches it uses are a really weird maxi switch rubber dome-type switch fastened with screws on a pcb. Here are some photos of it .
Really the only thing I could find out about this was that when it first came out, it costed 795$
Does anyone have an answer to what type of "switches" these are? And would it be possible to convert to ps/2 or usb for use as a macropad?

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31 Jan 2020, 08:01

The domes look like typical Maxi Switch domes from Maxi Switch dome with slider; they're essentially conductive domes over PCB. In this case they just use separate barrels rather than having a communal barrel plate. Also, looks like they dispensed with the sliders and integrated it into the keycap instead.


02 Feb 2020, 03:16

The shape reminds me of the IBM LPFK, though I couldn't say if it's just coincidence or not.


02 Feb 2020, 04:50

HP made an HIL to PS/2 converter, but they are probably hard to find.

The protocol is documented in ... _Jan86.pdf.

Someone might have already done it for a HP 46021A keyboard. The serial encoding will need to be bit-banged, because it has some address bits in it that a regular UART doesn't know about.

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15 Feb 2020, 02:50

Do domes with slider feel good by any chance?

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19 Feb 2020, 21:00

I don't know about the slider variant, but the ones in this HP keypad feel better than normal rubber domes. The reason I got it was because it felt different from other domes that I had tried. It feels quite tactile, and it's not as mushy as normal rubber domes, also it feels solid when bottoming out. Unfortunately with this keypad they way they key-caps are mounted causes quite a bit of binding on off-center presses.


25 May 2020, 04:54

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