Pinebook SDIO gpio control using SD card slot blog post

[machinehum]

This is a really cool idea, thanks for sharing.

The last post people are talking about issues with the current solution - I want to start a little opensource project designing a breakout for this, I can label all the pins and incorporate whatever else would be useful, LEDs, sensors, headers, etc...

Seeed can manufacture PCBs that are 0.6mm & 0.8mm, I believe a post above said they must not be thicker than 0.75mm, but the height of a uSD card is ~1mm - would the 0.6mm or 0.8mm be best?


I can also send out some free board for people. They'll be dirt cheep.

Let me know if anyone is interested in helping out (feedback, suggestions, etc...) we can set up a time on the IRC

~wlkr

I'm definitely interested in providing input !  

I think .8mm  would be pressing it;  but, really,  the best way to spec the end of the board is that it should look and be precisely identical (exactly) with a micro SD card !  --not thicker,  not thinner;

Also, it needs to be able to activate the spring latch correctly of a push-push slot like the one in the Pinebook.

The Sparkfun board works but is sloppy in both regards to the above two requirements.  The other brand does not work at all because its too thick to enter the slot... it won't even enter the slot of a carrier outside the Pinebook !

The wikipedia says they're 1mm thick? So I'm not sure why the 1mm thick PCB didn't work at all. It's possible they didn't pull the solder mask back far enough, so the FR4 is 1mm + solder mask > 1mm - is it close? or completely out to lunch?

It's difficult to get PCB's to an "exact" thickness, typically you just get whatever your CM offer.

Spring latch should be easy to do.

Do you have any other input? or is  a pure breakout good enough? I think it would be cool to get an STM32 or ATMEGA onboard as well, then you could piggyback of their peripherals and communicate over SPI. I think the key would be to keep it really small, so you can bring it around.