Question: how is your PCB/circuit?

Question

Question: how is your PCB/circuit?

ianliu opened this issue 2 years ago · comments

Hi Riskable,

First I would like to say: MOTHER F*#$%! GENIUS design! Congrats!

Second, how is your circuit implemented? Do you need a matrix of analog pins for this keyboard to work? Is it even possible to make an analog matrix?

How do you measure each key? Is there a coil under each key?

Thanks!

Ian Liu Rodrigues commented 2 years ago

Thanks!

Russ Nelson · Answer 1 · Thu Jan 27 2022 11:21:57 GMT+0800 (China Standard Time)

There is no Matrix unless you use Reed switches. If you use hall effect sensors, there is one for key, and you need one bit of IO per key.

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On Wed, Jan 26, 2022, 18:47 Ian Liu Rodrigues ***@***.***> wrote: Hi Riskable, First I would like to say: MOTHER F*#$%! GENIUS design! Congrats! Second, how is your circuit implemented? Do you need a matrix of analog pins for this keyboard to work? Is it even possible to make an analog matrix? How do you measure each key? Is there a coil under each key? Thanks! — Reply to this email directly, view it on GitHub <#5>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAI2PAWUX4PVZE234QX5NKLUYCB2JANCNFSM5M4M554A> . Triage notifications on the go with GitHub Mobile for iOS <https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android <https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>. You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

The Surgeon · Answer 2 · Fri Jan 28 2022 04:35:51 GMT+0800 (China Standard Time)

Any idea what hall effect sensors would be good to use? I looked at the kicad repo and there doesn't seem to be any recommendations.

Russ Nelson · Answer 3 · Fri Jan 28 2022 06:37:00 GMT+0800 (China Standard Time)

https://www.amazon.com/gp/product/B09PG3PGH6/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1

The Surgeon · Answer 4 · Fri Jan 28 2022 09:25:30 GMT+0800 (China Standard Time)

@RussNelson Any clues on SMDs, like in the example board repo?

Riskable · Answer 5 · Tue Feb 08 2022 04:57:43 GMT+0800 (China Standard Time)

For my boards I've mostly been using OH49E-S hall effect sensors. They're cheap and readily available.

Also note that I'm making a tutorial series talking about how to make your own analog keyboard PCB (parts 1 and 2 are up): https://youtu.be/TfKz_FbZWLQ

Udi Finkelstein · Answer 6 · Wed Feb 16 2022 15:22:42 GMT+0800 (China Standard Time)

Looking at https://github.com/riskable/void_switch_kicad/blob/main/symbols/49e.kicad_sym I see you also found:

https://lcsc.com/product-detail/Magnetic-Sensors_GoChip-Elec-Tech-Shanghai-GH39FKSW_C266230.html
It seems to be ~30% cheaper, at 0.1306$/unit (150PCS) vs 0.1984$/unit (100PCS).

Comparing the datasheet, it seems to have a compatible pinout, but it is slightly less sensitive (1.8mv/GS vs 2mV/GS for OH49E-S), and typically consume 6mA vs 4.2mA for the OH49E-S, which might be an issue in a keyboard with close to 100 switches, esp. if you want to power it from USB.

Do you have any actual experience with this part?

Riskable · Answer 7 · Sat Mar 19 2022 04:39:44 GMT+0800 (China Standard Time)

@udif Yes, I swap out OH49E-S for GH39FKSW based on what's available all the time. My firmware doesn't really care much about the sensitivity and both are approximately using the same amount of power when powered at 3.3V.