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Development board for two-key and four-key keypad enclosures
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Development board for two-key and four-key keypad enclosures

by HowdyMoto on Sun Oct 24, 2021 1:57 am

Hi there,

I just got these in the mail:
https://www.adafruit.com/product/5081
https://www.adafruit.com/product/5073

When I bought them, I wasn't sure what boards might fit in them, and now that I have them, it seems like nothing fits in them elegantly. The four-key enclosure has a project example that uses a RPi Pico RP2040, but the example shows the board floating in the enclosure without it being fastened to anything, which seems pretty janky. There's nowhere to fasten it down. Even pushing the Pico way back into the case doesn't let you use the screw holes in the back of the Pico - they're not far enough at the edge to let the screw go through them.

The two-key enclosure, as far as I can tell, is even worse. The smallest board I have, a Trinket M0, might fit, except that it blocks the screw hole that hold the back plate on to the enclosure, and then there's still no place to secure the Trinket.

Are there boards that fit in these enclosures nicely? Otherwise these enclosures seem a bit useless.
Attachments
IMG_0973.jpg
None seem to work.
IMG_0973.jpg (529.8 KiB) Viewed 301 times
IMG_0971.jpg
Various boards I might try
IMG_0971.jpg (554.42 KiB) Viewed 301 times

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Re: Development board for two-key and four-key keypad enclos

by mikeysklar on Tue Oct 26, 2021 6:59 pm

Looking at the four-key with pico setup you can see the photos from the guide how insulation is done with kapton tape and the board held in place with one screw and the acrylic bottom.

https://learn.adafruit.com/pico-four-ke ... ep-3104216

The two key I didn't see a guide that was using the Trinket or QtPy. The guide we have involves some 3D printing and is using a full size Feather nRF52.

https://learn.adafruit.com/deco-two-key ... on-feather

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Re: Development board for two-key and four-key keypad enclos

by johnpark on Wed Oct 27, 2021 2:29 pm

Yes, I don't know of a commercially available board for these enclosures, so they require some DIY -- anything from designing your own PCB to securing an existing board as I did in that guide. A nice middle ground would be to design a small 3D printed base for the case that holds the board snugly.

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Re: Development board for two-key and four-key keypad enclos

by swooby on Wed Nov 10, 2021 9:16 pm

HowdyMoto wrote:Are there boards that fit in these enclosures nicely? Otherwise these enclosures seem a bit useless.


I am in the identical boat; I bought multiple of the 1x2, 1x4, and 4x4 enclosures.
I thought the 5x6 snap apart PCB (https://www.adafruit.com/product/5157) might be of some use in the 1x2:

A 1x2 breakoff does not fit without a bit of sanding, and then a hole has to be drilled through the PCB. Zoinks!
PXL_20211111_011201093.jpg
PXL_20211111_011201093.jpg (809.51 KiB) Viewed 219 times

PXL_20211111_011239952.jpg
PXL_20211111_011239952.jpg (758.29 KiB) Viewed 219 times


The 1x2 product page (https://www.adafruit.com/product/5081) clearly says:
You provide the PCB in the housing and bolt it into this base. Makes for a prettier build with more protection than just layers of PCB or acrylic. While it's designed for a custom PCB, you could also just snap in 2 keys and 'free wire' them.

(BTW, that page's lower technical picture links are dead)

I don't mind some DIY, but I would think some other people that bought these might have open sourced their PCBs, but I briefly looked and did not find any.

Clearly the PCB will need to have the main guts of the QT Py RP2040 (https://www.adafruit.com/product/4900) or SAMD21 (https://www.adafruit.com/product/4600) dev boards on it.
Again, I am just surprised that something like this hasn't already been done and isn't already known by Adafruit that sells these.

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Re: Development board for two-key and four-key keypad enclos

by swooby on Wed Nov 10, 2021 9:41 pm

As a follow up, I think this would be a decent starting point to build a SAMD21 based PCB from.
https://github.com/adafruit/Adafruit-NeoKey-Trinkey-PCB
It has all of the required components, but the USB A etch should be replaced with a micro or C connector.

There is also this for a decent starting point for a RP2040 based PCB from:
https://github.com/adafruit/Adafruit-Trinkey-QT2040-PCB

Unfortunately I don't see a PCB of the single/1x1 NeoKey breakout (https://www.adafruit.com/product/4978) to get the footprint for the Kailh Switch Sockets (https://www.adafruit.com/product/4958), but you could always lift the footprint from the 1x4 or 5x6 PCBs:
https://github.com/adafruit/Adafruit-NeoKey-1x4-PCB
https://github.com/adafruit/Adafruit-Ne ... -Apart-PCB

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Re: Development board for two-key and four-key keypad enclos

by swooby on Thu Nov 11, 2021 4:02 pm

johnpark wrote:Yes, I don't know of a commercially available board for these enclosures, so they require some DIY -- anything from designing your own PCB to securing an existing board as I did in that guide. A nice middle ground would be to design a small 3D printed base for the case that holds the board snugly.


As another follow up, the "NeoKey 1x4 QT I2C" (https://www.adafruit.com/product/4980) is a reeeeeally close fit!
PXL_20211111_193806817_2.jpg
PXL_20211111_193806817_2.jpg (778.77 KiB) Viewed 203 times


I know it may be a lot to ask, but it would be awesome if that board could be slightly reworked to fit in that enclosure.
As a tinker/maker demo, it is acceptable to use an umbilical STEMMA QT cable out to a QT Py RP2040 or SAMD21, similar to this project:
https://learn.adafruit.com/neokey-1x4-qt-i2c

Obviously it would be more ideal to have a custom fit PCB with a RP2040 or SAMD21 onboard, but that is acceptable to be an exercise for the builder (to either design or find).

One other nitpick: The port opening of the Four Key Aluminum Keypad (https://www.adafruit.com/product/5073) is just a hair too small for a USBC male to fit in to.
PXL_20211111_195634435.jpg
PXL_20211111_195634435.jpg (376.83 KiB) Viewed 203 times

Nothing that cannot be easily solved, but it would have been nice if the case was designed to accommodate a USBC connection.
The 1x2 little sibling's port is much bigger and easily accommodates a USBC connection.

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Re: Development board for two-key and four-key keypad enclos

by swooby on Fri Nov 12, 2021 1:44 am

With the "NeoKey 1x4 QT I2C" (https://www.adafruit.com/product/4980), if you are real careful, and don't mind losing the INT trace on the top header (you'll still have it on the bottom header) then you can drill out two holes with a 5/32" drill bit and it will be a darn tight fit in the four-key enclosure (https://www.adafruit.com/product/5073).
PXL_20211112_052256425.jpg
PXL_20211112_052256425.jpg (362.22 KiB) Viewed 198 times

PXL_20211112_034056984.jpg
This was with a 1/8" bit, that already took out the INT trace to the top header; a 5/32" bit finished it off.
PXL_20211112_034056984.jpg (405.73 KiB) Viewed 198 times


Then you can run a STEMMA QT cable out to a QT Py RP2040 (pictured) or SAMD21.
PXL_20211112_052712230.jpg
PXL_20211112_052712230.jpg (563.81 KiB) Viewed 198 times


The QT cable I am using is short, but you could use one a little longer and wrap it in heat-shrink or even shield it to make it more durable.

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Re: Development board for two-key and four-key keypad enclos

by swooby on Wed Nov 17, 2021 9:00 pm

I just found this today, https://shop.pimoroni.com/products/keybow-2040:
Keybow 2040.png
Keybow 2040.png (623.9 KiB) Viewed 151 times


I suspect it's main board should fit perfectly in the 4x4 enclosure:
https://www.adafruit.com/product/5071
5071-03.jpg
5071-03.jpg (547.73 KiB) Viewed 151 times


I bought one and will report back here when it gets in in 10-14 days and I have tried in out.

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Re: Development board for two-key and four-key keypad enclos

by HowdyMoto on Thu Nov 18, 2021 3:02 am

Thanks, that looks perfect. Looking forward to your report.

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Re: Development board for two-key and four-key keypad enclos

by swooby on Mon Nov 22, 2021 9:07 pm

Here is my first pass at a 1x2 PCB for the 1x2 enclosure:
https://easyeda.com/editor#id=fd4bab7e0 ... 0157796293
Screenshot 2021-11-22 161519.jpg
Screenshot 2021-11-22 161519.jpg (214.49 KiB) Viewed 111 times

Screenshot 2021-11-22 170234.jpg
Screenshot 2021-11-22 170234.jpg (222.24 KiB) Viewed 111 times

Screenshot 2021-11-22 170343.jpg
Screenshot 2021-11-22 170343.jpg (133.96 KiB) Viewed 111 times


I'm a novice at designing PCBs, so any feedback or correction you can find on it would be appreciated.
I will probably send this off for fab in a few days.

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Re: Development board for two-key and four-key keypad enclos

by mikeysklar on Tue Nov 23, 2021 12:46 pm

Nice looking board. Did you need to create the Kailh footprint or did EasyEDA have that?

Some of your pads and silkscreens are really close to the edge. Depending who is printing your boards tolerance can be between 10 - 40 mil of space from edges.

Screen Shot 2021-11-23 at 8.42.10 AM.png
Screen Shot 2021-11-23 at 8.42.10 AM.png (3.14 MiB) Viewed 103 times

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Re: Development board for two-key and four-key keypad enclos

by HowdyMoto on Tue Nov 23, 2021 1:37 pm

This is the board I was hoping Adafruit would make. If it turns out well, I'll order a few!

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Re: Development board for two-key and four-key keypad enclos

by swooby on Tue Nov 23, 2021 1:51 pm

mikeysklar wrote:Nice looking board. Did you need to create the Kailh footprint or did EasyEDA have that?

Some of your pads and silkscreens are really close to the edge. Depending who is printing your boards tolerance can be between 10 - 40 mil of space from edges.

Screen Shot 2021-11-23 at 8.42.10 AM.png


Thanks! EasyEDA had several footprints, but in the end I just lifted a single tile out of the "NeoKey 5x6 Ortho Snap-Apart" .brd at:
https://github.com/adafruit/Adafruit-Ne ... -Apart-PCB

I may make one more attempt to lay out the Kailh tile by hand instead of using that fixed/inflexible footprint.

Since posting those pics I had already re-worked the board a bit to move those two corner pieces in a bit.

Final touches and simple parts inventory and then off to the fab and then wait and assemble myself and see if it works.
Is there a [free] way to **virtually** test PCB design for functionality before it is fab'ed?

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Re: Development board for two-key and four-key keypad enclos

by mikeysklar on Tue Nov 23, 2021 7:54 pm

What kind of virtual testing for the PCB did you have in mind?

The one thing most PCB software has (this includes EasyEDA) is DRC (Design Rule Check). Which is settings for clearance, track widths and via sizing.

https://docs.easyeda.com/en/PCB/Design- ... index.html

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Re: Development board for two-key and four-key keypad enclos

by swooby on Tue Nov 23, 2021 10:13 pm

mikeysklar wrote:What kind of virtual testing for the PCB did you have in mind?

The one thing most PCB software has (this includes EasyEDA) is DRC (Design Rule Check). Which is settings for clearance, track widths and via sizing.

https://docs.easyeda.com/en/PCB/Design- ... index.html


I figured in 2021 there are virtual PCB simulators that can take a PCB design and virtually apply power to it and see if it blows up or not.
Obviously the internal SAMD21 logic would be more difficult (but not impossible) to emulate, but at least some ability to test the discrete/passive components for smoke or not.

Final version that has been sent off to jlcpcb for fab:
Screenshot 2021-11-23 175655.jpg
Screenshot 2021-11-23 175655.jpg (197.86 KiB) Viewed 95 times

Screenshot 2021-11-23 175651.jpg
Screenshot 2021-11-23 175651.jpg (230.63 KiB) Viewed 95 times

If I were to change anything else, it would be to relabel the U1, U2, U3.

Exciting stuff is about to happen! :)
Screenshot 2021-11-23 175335.jpg
Screenshot 2021-11-23 175335.jpg (55.96 KiB) Viewed 95 times


First time I have tried their assembly service.
I'll update this thread when I know how it works!

BOM1:
"LCSC Part Number","Manufacturer","Manufacture Part Number","Quoted Manufacturer","Quoted LCSC Part Number","Quantity","Unit Price","Order Price","Quantity Available","Min\Mult Order Qty","RoHS","Part Match Confidence"
"C1713","SAMSUNG","CL21A106KOQNNNE","Samsung Electro-Mechanics","C1713","1","0.0094","0.94","1462600","50\50","yes","100%"
"C1589","SAMSUNG","CL10B103KB8NNNC","Samsung Electro-Mechanics","C1589","1","0.0024","0.24","3352200","100\100","yes","100%"
"C1592","SAMSUNG","CL10A105KO8NNNC","Samsung Electro-Mechanics","C1592","4","0.0033","1.32","8203900","50\50","yes","100%"
"C84367","MDD","1N4148W","MDD(Microdiode Electronics)","C84367","2","0.009","1.8","28550","50\50","yes","100%"
"C25992","UniOhm","0603WAJ0222T5E","UNI-ROYAL(Uniroyal Elec)","C25992","1","0.0011","0.11","756300","100\100","yes","100%"
"C843670","G-Switch(品赞)","GT-TC030A-H020-L1N","G-Switch","C843670","1","0.0648","6.48","1335","5\5","yes","100%"
"C379349","Jiangsu RUNIC Tech","RS3236-3.3YF5","Jiangsu RUNIC Tech","C379349","1","0.0676","6.76","8990","5\5","yes","100%"
"C10418","ValuePro","micro USBFemale","Jing Extension of the Electronic Co.","C10418","1","0.0512","2.82","38735","5\5","yes","0%"

BOM2:
2x NEOPIXEL REVERSE MOUNT RGB LEDS: 10 pack at https://www.digikey.com/en/products/det ... 0/14302512
2x KAILH SWITCH SOCKETS FOR MX-COMP: 20 pack at https://www.digikey.com/en/products/det ... 8/13997772
1x ATSAMD21: https://www.mouser.com/ProductDetail/55 ... D21E17D-AU

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