Bonk Button
There's a meme where someone is smashing a button with some kind of annotation on it. I wanted to make that meme in real life. In particular, I wanted to make the button make the "bonk" sound effect so my D&D group could use it when someone got hit in the campaign. I did not find any videos on how to do this in a simple project, so I had to design my own solution.
Component Selection
I wanted this to be a simple project that anyone could do and that didn't take much skill to put together. Therefore, I tried to minimize the number and cost of the components. In the end, the Bill of Materials consists of only a handful of parts:
-DFPlayer Mini and SD card
-Pushbutton
-Speaker
-9V battery and connector
-Voltage regulator
-Wire/Dotterboard
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The heart of the project is the DFPlayer Mini, which is essentially the computer and amplifier for an MP3 player. It also only costs $2-$4.
Schematic and breadboard
Using the datasheet for the DFPlayer Mini, I found that I needed to use a voltage regulator in the final product because it only accepts 3.2-5VDC as input voltage. I also learned that by grounding the ADKEY_1 pin, I could play the first (and only) track that would be stored on the SD card, which would contain our sound effect.
Using this information, I created a schematic and tested the circuit on a breadboard (though I used a power supply instead of a 9V battery with a voltage regulator). To my pleasure, the circuit worked!
PCB
I designed the circuit using KiCad and designed a PCB, which I ordered 5 of from PCBway. To my surprise, the boards worked on the first try!
Skeleton assembly
With the PCBs made, I assembled a clean version of the Bonk Button. At this point, I am happy with the design for personal use, though if I want to share the design, it needs a housing, a PCB design that can fit in the housing, and a way to turn the button on and off easily.
Future goals
After testing, I would like to create PCBs to either sell or open source and I would like to design a 3d-printable cover so that the button is easier to "smash" since pressing the pushbutton is a little finicky.