New card idea

Guys,

MrsCrossRoads was doing some work with Raspberry Pi’s recently, with no good way to connect to the headers on them. There are Pi shields out there, but they cover up the internal connecters, so she wanted a shield that left those accessible and only broke out the male pins, 13x2 on one board, and 20x2 on another.

I came up with this, with no real pin names as the signals have different names/functions between boards.
Left some terminals on the side to use as extra power & Gnd distribution points, but without being connected to any of the header pins.

Then it occurred to me this could be used with a Mega too, so I labelled the bottom so it could be plugged onto a Mega’s 18x2 header, with the extra 2x2 pins off to the right of the 5V/D20, D21 side of the board to not intefere with the Analog header.

Install a female long tail header and plug onto a Mega. Same connector with board flipped over and the female headers plug onto a Pi. Put on male headers and use a 2x20 ribbon cable and extend the header away from the Pi. Plug a male-male header into the Mega and do the same. Mount the screw terminals top or bottom as needed.

What do you think? Print these out & lay them back to back to see the effect.

RaspPiScrewShieldTop.pdf (30.8 KB)

RaspPiScrewShieldBottom.pdf (19 KB)

I don't have a Mega or a Pie but if it's for Mrs. Crossroads; you had better do a good job of it or else you may not see for a few days and may have to make your own sandwiches ;)

Where's my "Two Pin GND Test Point" and can't we put a led on there for something?

Otherwise sounds like a great idea.

Looks good.

Is it Raspberry Pi for Teens? ;)

I have a few break out board designs some are here:- http://www.thebox.myzen.co.uk/Raspberry/Breakout.html

http://www.thebox.myzen.co.uk/Raspberry/Buffer_Board.html

And this is interesting about the output

http://www.thebox.myzen.co.uk/Raspberry/Understanding_Outputs.html

Ok, I’ll add a place to connect a ground probe.

GM, I have to wait till I get home to see your sites, too hard to read on a smartphone.

I am probably wrong, I cannot get the images straight in my mind for the Mega: But, you may want to double check that GND is definitely on the left side with +5V on the right for the daughter card.

I like the convertible idea.

What are the As and Bs on the side terminals for?

Can connect one side to 3.3V, the other to 5V, both to the same.
Pi headers vary from board to board apparently, so I didn’t connect what would be the power terminals on the side to any of the 2x18/2x20 pins. Run a wire from the appropriate screw header out to A or B as needed.

Print out and put the two images back to back. I had myself convinced last night I had it correct. The unmarked Mega pins should hang off the Mega board near the D21, 20, 19 header.

Is there any need to have mounting holes on the out side corners for standoffs? 4-40 or 6-32
Could have them in center, between the terminal strips

Edit:

Can connect one side to 3.3V, the other to 5V, both to the same.

Maybe have two pin jumpers that can simply be shorted to achieve the desired voltage needed.

Will look at mounting holes. I think in the center would interfere with wires that get routed to those screw terminals.

Voltage jumpers - only 5V/Gnd is available from Mega, on the "end" pins. I could add some holes to make those connections easy. 3.3V/Gnd from the Rasp Pi, on varying pins.