monic part 3: towards a handheld

monic part 3: towards a handheld - Printable Version

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monic part 3: towards a handheld - F-73P - 07-01-2020 01:54 AM

Previous: monic part 2: connecting the keypad

Next: monic part 4: arbitrary-precision rational arithmetic

I will now place the display and matrix keypad on veroboard. The calculator can then be connected to a development board (such as the NXP i.MX RT1010 I have been using so far) via terminal blocks on the left of the veroboard.

I am also trying to find keycaps for the Omron B3F-1052 pushbuttons; any suggestions?

RE: monic part 3: towards a handheld - Maximilian Hohmann - 07-01-2020 10:17 AM

Hello!

Very interesting project, looking forward to see more of it.

(07-01-2020 01:54 AM)F-73P Wrote: I am also trying to find keycaps for the Omron B3F-1052 pushbuttons; any suggestions?

I have used this kind for some tinkering projects in the past (this is an eBay-link, unfortunately I couldn't find them anywhere else - they come from China anyway, no matter who you order them from):

https://www.ebay.com/itm/A14-Tactile-Cap-Switch-Momentary-Button-Square-Flat-Keycap-6-Colours-/233216076402

You can select a keycap in the colour you like and snap a transparent cover over it. The gap between keycap and cover is large enough for a key label printed on solid/thick paper. These caps should also fit your Omron switches, but better compare the measurements.

Regards
Max

NB: Maybe I missed it in your earlier posts, but what does "monic" stand for?

RE: monic part 3: towards a handheld - Garth Wilson - 07-23-2020 04:02 AM

(07-01-2020 01:54 AM)F-73P Wrote: I am also trying to find keycaps for the Omron B3F-1052 pushbuttons; any suggestions?

We use them in a couple of our products at work. Availability has never been a problem at all. See https://www.mouser.com/Electromechanical/Switches/Switch-Accessories/Switch-Bezels-Switch-Caps/_/N-cbtcd?P=1yzp40a&Keyword=Omron+key+caps&FS=True

RE: monic part 3: towards a handheld - Chr Yoko - 07-28-2020 09:21 PM

Very nice project !
Your chosen microcontroller looks very powerfull , why such choice instead of a 32bits Arduino such as a STM32 base ?

Hereby EEVblog that is showing how to get made a custom membrane keyboard :
https://www.youtube.com/watch?v=H8XBBfvsPj0
From here :
https://www.jrpanel.com/switch/buy/
(exemple @ about US$255 for 4 parts, with embossed keys , their stainless domes and 4 colors on the overlay)

[Image: JRPanel-Membrane_switch-Graphic_overlay.gif]

[Image: JRPanel-Membrane_switch-Graphic_overlay.gif]

OK, bit expensive and not as good as a real keyboard, but has a professionnal look to it.

Also I would be interrested by the software side of your project ;-)

RE: monic part 3: towards a handheld - F-73P - 08-01-2020 05:58 AM

Thanks for the suggestions. I've ordered Japanese "Alps Alpine" switches and keycaps, and have started making some keypad labels.

(07-28-2020 09:21 PM)Chr Yoko Wrote: Your chosen microcontroller looks very powerfull , why such choice instead of a 32bits Arduino such as a STM32 base ?

The i.MX RT EVK boards offer speed and large memories, and the IDE is free and supports programming in C and assembly.

(07-28-2020 09:21 PM)Chr Yoko Wrote: Hereby EEVblog that is showing how to get made a custom membrane keyboard :
https://www.youtube.com/watch?v=H8XBBfvsPj0
From here :
https://www.jrpanel.com/switch/buy/
(exemple @ about US$255 for 4 parts, with embossed keys , their stainless domes and 4 colors on the overlay)
OK, bit expensive and not as good as a real keyboard, but has a professionnal look to it.

Thanks for the links, they look great. Definitely something to keep in mind for the future.

RE: monic part 3: towards a handheld - F-73P - 10-25-2021 08:27 AM

Handheld prototype 1.0 is finished.

Schematics:

[Image: 51627501993_b24c5157b7.jpg]

Soldering the wires, buttons and connectors to the veroboard:

[Image: 51628135605_ef23e914a9.jpg]

Attaching the display and spacers:

[Image: 51626448627_773134aa32.jpg]

Connecting the microcontroller:

[Image: 51627497843_d4818b3b6d.jpg]

The shift functions:

[Image: 51627495098_245fe91d21.jpg]

The final result:

[Image: 51626443852_cc1801b291_b.jpg]

RE: monic part 3: towards a handheld - F-73P - 09-10-2022 08:58 AM

Recently I bought an MIMXRT1160-EVK development board and 5.5" display. All going well I'll use these to make a second prototype featuring a QWERTY keypad.

[Image: 52347184258_0582d110a9.jpg]

RE: monic part 3: towards a handheld - Chr Yoko - 09-12-2022 11:51 AM

Brilliant ! Thanks to keep us informed !

Maybe you want to create a kind of Sharp PC G850VS ?
(Basic ; C ; Z80)

[Image: maxresdefault.jpg]

RE: monic part 3: towards a handheld - F-73P - 09-16-2022 05:22 AM

(09-12-2022 11:51 AM)Chr Yoko Wrote: Brilliant ! Thanks to keep us informed !

Maybe you want to create a kind of Sharp PC G850VS ?
(Basic ; C ; Z80)

Thanks, yes something similar:

[Image: 52361480519_b045d23b9d.jpg]