Advanced users • GPIO headers on bottom, again

Hi,

I know this has been asked before, but none of the previous answers have worked for me, so I figured it couldn't hurt to ask again: I'm trying to use a Pi 4 B with its GPIO header plugged into a socket on a custom board. For that, I need the GPIO header on the bottom, but all the Pis in question only come with headers pre-assembled on the "wrong" side.

I tried desoldering the GPIO header and putting a new one in. It's a massacre, and I'm concerned about the mechanical stress on the pads and traces, and the high temperature and/or soldering time needed specifically for the GND pins. It kind of worked, but I also destroyed some traces on one of the boards, and overall it's not pretty. Some peripherals have also just stopped working after a while. It seems unlikely, but I fear that this might be related to the heat, so I'm trying to just avoid desoldering the original header.

Here are some other options I've already considered or tried:

• I can't use any of the Pi Zeros. Mostly due to lack of 5GHz WiFi (I need it, I tried). Also potentially not enough RAM and peripherals (USB, Ethernet).
• I don't want to plug my custom board in at the top (HAT style). The custom board is larger than the Pi, and it would be very awkward.
• I'm trying to avoid running a cable (or similar) from the Pi to my socket. Wouldn't hold the Pi in place. Might also degrade signal integrity for some faster signals (SPI).
• I'm considering just using something other than a Pi. I previously used an ESP32, but the code has outgrown that.

I'm at a point where I'm considering just keeping the original GPIO header, and soldering some clipped right-angle pins to the "stumps" of their pins on the bottom. I've also read about cup-style pogo pins that I could maybe solder individually to the bottom, but I don't want their "pogo-ness".

Any other ideas?

Statistics: Posted by alemariusnexus — Mon Jan 13, 2025 4:52 pm — Replies 5 — Views 71

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