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MintyPi Keyboard?

Posted: Wed May 02, 2018 5:54 pm
by DPSquid
A bit of a dumb question, but does anyone think there would be any way to replace the 4 button + D-pad, with a keyboard?
This would probably effect the screen to just remove the MintyPi Pcb, do you think there would be any work around for this?

Re: MintyPi Keyboard?

Posted: Wed May 02, 2018 7:03 pm
by Sushi
AFAIK, no keyboard that small exists. It could be done if a keyboard pcb was developed. Otherwise, you can program an arduino 32u4 micro to drive a touch screen.

Re: MintyPi Keyboard?

Posted: Wed May 02, 2018 8:57 pm
by DPSquid
Sushi wrote:
Wed May 02, 2018 7:03 pm
AFAIK, no keyboard that small exists. It could be done if a keyboard pcb was developed. Otherwise, you can program an arduino 32u4 micro to drive a touch screen.
Most tiny keyboards are too large, at 100mm. But that's not really too big of a problem, i'm sure there's a way around it. But what about the pcb, and the connected hardware?

Re: MintyPi Keyboard?

Posted: Thu May 03, 2018 2:56 am
by Helder
Get a Bluetooth keyboard and done.

Re: MintyPi Keyboard?

Posted: Thu May 03, 2018 9:45 am
by ICMF
If you're thinking about making a mini laptop or similar, it wouldn't be impossible. You'd need to design your own PCB, but adding a bunch of button contacts would be relatively straightforward; you could scavenge a keyboard and membrane contacts from an old Blackberry, or DIY something. You're basically doing this:

https://www.youtube.com/watch?v=Ko7eNx0zAuI

Re: MintyPi Keyboard?

Posted: Thu May 03, 2018 11:01 am
by DPSquid
ICMF wrote:
Thu May 03, 2018 9:45 am
If you're thinking about making a mini laptop or similar, it wouldn't be impossible. You'd need to design your own PCB, but adding a bunch of button contacts would be relatively straightforward; you could scavenge a keyboard and membrane contacts from an old Blackberry, or DIY something. You're basically doing this:

https://www.youtube.com/watch?v=Ko7eNx0zAuI
That would work, but if I was sticking to the MintyPi design, how would the screen play into this?

Re: MintyPi Keyboard?

Posted: Fri May 04, 2018 10:56 am
by ICMF
The circuitry for the screen would be the same. The safe shutdown circuitry could be the same, even. You're just mashing the basic keyboard circuit design into the MintyPi form factor. So instead of having ^V<> ABXYLR start and select, you'd have (up to) 36 keyboard buttons wired into a 'grid' 6 rows and 6 columns. (the keyboard doesn't have to be a grid, but the circuit is) Up would become Row 1, Down would be Row 2, A would be Column 1, B would be Column 2, etc. So pressing a key sends a signal to a GPIO pin for a row and column, and each key will trigger a different pair of pins - A = 1,1; B = 1,2... Z = 6,6. You would then have to create a piece of software so the Pi could map those GPIO inputs and translate them into keyboard inputs - so it would know that when it gets a signal on GPIO pins 17 and 23, it should interpret that as a keyboard input for the letter 'F'.

Basically, all the electronics would be the same. The only difference is that, instead of having 8 contacts on top of the PCB, you'd have 36 contacts in your keyboard layout, which would route back to the same 12 GPIO pins that the Minty Pi currently uses. Then you'd have to re-design the faceplate so that it incorporates a keyboard. The mechanical aspect of making a functional keyboard would probably be the hardest part. Or alternatively, figure out a way to wire in something like a Blackberry keyboard (so your GPIO pins would route to a ribbon connector), then design a new faceplate to hold it. If you go the Blackberry route, it saves you the difficulty of engineering functional, miniature keys, but adds the difficulty of reverse-engineering their keyboard layout.

So, it should be possible, and it seems relatively straightforward in terms of what you'd need to do, but it wouldn't be a simply project.

Re: MintyPi Keyboard?

Posted: Sun May 20, 2018 10:36 pm
by Trekintosh
I want to chime in a little late but the XBox 360 chatpad is probably the smallest usable option you’ll have, an you still can’t use an Altoids tin. I’m making my own pocket PC using one, using some kind of rolling tobacco tin that’s 2.5”x4”, and that provides plenty of room. I also have this vintage first aid tin(pictured) that’s iirc 2.5”x3.5” and it spreads the sides a bit to put the keyboard in.

The only other keyboard option I can think of would be a derivative of @moosepr’s Pi0cket Click keyboard with its snap domes on a custom PCB that’s mintypi sized. I’d buy such a pcb if you make one.

Re: MintyPi Keyboard?

Posted: Thu May 24, 2018 8:37 am
by DPSquid
Trekintosh wrote:
Sun May 20, 2018 10:36 pm
I want to chime in a little late but the XBox 360 chatpad is probably the smallest usable option you’ll have, an you still can’t use an Altoids tin. I’m making my own pocket PC using one, using some kind of rolling tobacco tin that’s 2.5”x4”, and that provides plenty of room. I also have this vintage first aid tin(pictured) that’s iirc 2.5”x3.5” and it spreads the sides a bit to put the keyboard in.

The only other keyboard option I can think of would be a derivative of @moosepr’s Pi0cket Click keyboard with its snap domes on a custom PCB that’s mintypi sized. I’d buy such a pcb if you make one.
Where did you get your tin?

Re: MintyPi Keyboard?

Posted: Fri May 25, 2018 10:56 am
by Trekintosh
DPSquid wrote:
Thu May 24, 2018 8:37 am
Trekintosh wrote:
Sun May 20, 2018 10:36 pm
I want to chime in a little late but the XBox 360 chatpad is probably the smallest usable option you’ll have, an you still can’t use an Altoids tin. I’m making my own pocket PC using one, using some kind of rolling tobacco tin that’s 2.5”x4”, and that provides plenty of room. I also have this vintage first aid tin(pictured) that’s iirc 2.5”x3.5” and it spreads the sides a bit to put the keyboard in.

The only other keyboard option I can think of would be a derivative of @moosepr’s Pi0cket Click keyboard with its snap domes on a custom PCB that’s mintypi sized. I’d buy such a pcb if you make one.
Where did you get your tin?
I got it from ebay. The seller I bought mine from (5x tins for $15) doesn't seem to list them anymore, but I found this listing. https://www.ebay.com/itm/RAW-Rolling-Pa ... 3612841963

If you search for "Raw Tin" on ebay, you'll get a bunch of different ones, just look for the ones that look like this:

Image
Image

Yeah, the exterior styling is pretty awful. I plan on taking some acetone to mine and tearing all that nasty paint off, then making my own decals. The "RAW" on the lid is embossed, so I might go with like "RAW Pi" or something like that.