Ah I see. I hadn't thought about using all the pins. This brings out 23 of them and is about the same size as the stamp: https://www.adafruit.com/product/4888

Ah I see. I hadn't thought about using all the pins. This brings out 23 of them and is about the same size as the stamp: https://www.adafruit.com/product/4888 https://www.adafruit.com/product/4888 This brings out 20 and has castellated pads: https://www.adafruit.com/product/5302 https://www.adafruit.com/product/5302 This is bigger but fancier, has a lipo charger and other stuff. I think it brings out all available pins, though the # mentioned is 21. More of an SBC than a solder-down, I guess. I have one (old version) but am trying to figure out where I left it: https://www.adafruit.com/product/5302 https://www.adafruit.com/product/5302