Sound reacting skull. Reacts to claps, shouts and other noises you make. It responds by lighting up in different colors and talking with its mouth furiously.

Demo video of the actual project:

https://www.youtube.com/shorts/iANHCO4711A

Supplies

You will need 3D printer to print your model. I used P1S printer and JEYO PLA matte white for this project.

You will also need some electronic parts and bolts.

I used M3 bolts. If you design your bolt holes tight enough, the bolts will cut into the plastic and you don't need nuts to attach the bolts. You will also need to do some soldering.

Electronics:

LED strips. I used couple WS2812B led strips with different led spacings
Wemos D1 mini or some other micro controller. I used fastled library to program the LEDs
SG90 Micro servo for operating the jaw
Microphone Amplifier Module MAX446
LM2596S DC-DC DC adjustable step-down power supply module to lower voltage to 5V
9V battery and 9 battery cable
Powerswitch
button with pulldown resistors (optional, I didnt end up using that)

Step 1: Modeling a Skull

I used fusion360 forms to create a skull with reference image. You can find many good reference images from google. Just scale it to your liking before starting to model. At this step I did make a small mistake on underestimating how much space the electronic parts would need. I ended up designing a small storage box as an extension of the skull to fit all the electronics into.

Printing part was not as easy as you would expect. Having some details on the Z axis probably caused some problems with quality, but with changing print orientation the results ended up being ok.

Step 2: Soldering

There is quite bit of soldering you have to do.Luckily the connections are pretty simple. I made the mistake of having too little installation space on the 3D printed skull and bad planning of wire routes. As a result of having too little installation space I did break up soldering connections MANY times. So you should do some space planning before commiting on the design. I wanted to make really minimalistic design but that's really hard if you dont have custom PCB.

At least I got my soldering tuned in with this project. I'm not that experienced with soldering after all

After all soldering is done you should upload test program to Wemos D1 mini and see if everything works properly

Step 3: The Assembly

The assembly for me was HARD. No wasted space and I had to re-design some parts since original desin left no space for electronics. In the end the results came up pretty fine. The last layer is 9V battery for easy battery change and the power switch is hidden nicely behind the skull.

Step 4: Final Product

The end product is a nice sound reacting skull. There was so much that went into this project that it's almost exhausting trying to even summarize the project. All and all it was a fun challenge. I had no experience in fusion360 forms, servos nor with the amplifier module...I learned a lot in this project. Hope you enjoy this as well.