Hi folks, planning on building a raspberry pi zero hardware interposer for the picocalc, for sure I think i can get the display working via fbtft, the keyboard, and likely the pwm audio, everything else though is a mixed bag, if I get a pcb rolled, who here can help push this across the line? basically need TF slot support, power managment stuff, and generally just roll this all up into a nice install script. whos in?
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TF will probably be as easy as the LCD. As for power management, a bit of modification to the keyboard firmware should let you access the power button input for software shutdown as well as command the axp chip to cut off power.
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How will you house it.
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I’m pretty sure it can all still fit in the case. I haven’t received my picocalc yet, but I can certainly fit one…
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I checked against the cad files, shouldn’t be an issue
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somebody made this GitHub - bablokb/pcb-pico-pi-base: An Interface PCB to use Pi-Hats with a Pi-Pico(w)
electrically, it seems complete, minus a buck boost to take 3.3v to 5v for running a pi
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dont have my pico calc yet, can someone check the vbus pin and see if it produces v5 without a pico present?
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From what I’m seeing in the schematics it seems VBUS_IN will be 5v only when USB-C is plugged in, and otherwise it’s battery voltage (or maybe 0v?!?)…
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That’s what I’m thinking, if that’s the case this just got way easier to make this work
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With no batteries or Pico in the main board, applying 5V with USB-C over a tested functional power supply, I read 0V between VBUS (the socket meant for the Pico’s pin 40) and GND (socket for pin 38).
Sorry for the weird angle etc.; it’s hard to take a picture while holding two probes.
I encourage someone else to take the same measurement to ensure it’s not just me. I also can’t test with battery power yet.
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thanks for looking into this, i wonder if the power circuit has to be latched on to send power
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alright, here is the first board version, just the display, the spi stuff for the keyboard, and pwm audio, nothing else, gonna fire off one to pcbway, will update with results in a week or so
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Great work! Will it fit in the existing case? Is the pico facing out or tucked in reverse?
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I suppose it could go on either side, depends how you solder the header
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It looks like you are planning on having the HDMI and USB interfaces exposed to the outside edge?
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eventually, this is just to see if i can get the basics working, if I can pull this off, i will definitely make an updated design and back shell to make everything pretty so folks can get at the ports
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I would be interested in this would love some Pi zero power under the hood. Once you have the board i would like to order for sure.
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Another cool idea is to use pogo pins for the zero so that other boards could be swapped in.
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Just curious if this will work
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