D1 Mini X-Pad Shield

The first prototype used whatever buttons I have at hand at the moment — they weren't very good. Now the buttons I ordered for it arrived, so I assembled a second prototype. Unfortunately, the buttons I ordered are too big, so I had to wrap their legs under them. But it works and doesn't look too bad.

The PCB arrived from OSHPark, and it works. You can order it at: https://oshpark.com/shared_projects/J8a9MVbO

I'm not happy with the buttons -- I used some cheap SMD buttons that I had on hand, but they are not really designed for being pushed directly by fingers. I might try gluing something on top of them, so they work better.

I used a chip socket for the chip, and the whole thing is rather high. In the future, I would probably use a different chip, in SMD version, and maybe even put it on the bottom.

All in all, it works well enough and I'm quite happy with it.

need an easy way to add user input capabilities to my D1 Mini boards. A joystick and some buttons would be probably the most versatile approach -- I could also use an encoder, like I did for #Nano TTY, however, that works well for menus, but not so good for games, and I want to try making some games too in the future. So I need something roughly like a game pad. A 4-way joystick, at least two buttons (accept and back), possibly a third button for start/settings, and possibly the fire button on the joystick. That's eight buttons together. Since the ESP8266 doesn't have a lot of GPIO pins, I will probably use a port expander -- this way I can just connect it to the I²C bus.

Next, I need to choose the layout for this shield. Using a standard D1 Mini shield shape doesn't seem like a good idea, because I want to be able to stack this with the display and led matrix shields. I could probably use the "double" shield for this, but it would be better if the buttons and joystick were accessible even if it's not the top shield.

I considered several options:

I even considered more exotic solutions, like putting all the buttons on the sides of the board, so that they are accessible -- but that's hard to do with the joystick, and makes it too easy to press the reset button accidentally.

I finally decided to use the last design on that image above. Yes, it's going to be problematic with the double shield -- but that can be worked around by making one of the stacks higher.

I couldn't sleep last night, so I got up and designed the PCB for this in Fritzing. I'm going to use the good old PCF874 port expander, even though it's a bit dated and weird to use -- but at least it's easy to get. Routing everything properly on such a small board was a bit tricky, but finally I even managed to add the footprints for the I²C pullup resistors and the address selection jumpers. I'm pretty happy with how it came out:One trick I had to do -- I put the joystick up-side-down. It won't affect anything, but it makes it easier to route the ground pin for it. Now just waiting for the PCB.