• PCB Design

    Sanjit Sarda • 09/21/2024 at 06:44 • 0 comments

    Version 1

    To design the board outline I used Illustrator. I looked up snowman designs and for some reason got hung up on designing them using 3 circles. I ended up designing a 4 layer board, and since I wanted to order it in white, this ended up becoming quite expensive and not feasible.

    Version 2

    So instead of that, I realized that making a 2-circle snowman would increase the surface area of the board, so I was able to design a 2-layer PCB out of it. After redesigning the board I also made it look a lot better than it did before(I added a top hat at a 10° angle). I rearranged the Neopixels and the rest of the components on the board(and also slanted some of the components so they looked better on the top hat lol). 

    Apart from those details, the PCB design was not too hard. I mostly used the typical application note of the datasheet for layout examples, but since I was using 0805 components(oops I forgot to mention that before), I had to improvise.

  • Schematic Design

    Sanjit Sarda • 09/21/2024 at 06:25 • 0 comments

    There were a few parts of the design.

    Attiny

    I used an ATTiny24(Equivalent to 44/84). I added a programming header, an LED for the nose, and connected it to the speaker(hopefully I can program this). The only slightly complicated part was that there were not enough pins to drive it using a differential drive(this is an idea I got from ATTiny Low Power Prank). I connected the speaker to MISO/MOSI, and then attached a connector that I could bridge with a shunt. I'm quite sure there is a better way to do this, but I am not sure what that would be.

    Charger/Power Management

    In the version without a LiPo Charger, I used a 5V linear regulator, so I can probably use any battery/power source over 5V to power it. 

    The charger version implemented(aka copied) Adafruit Powerboost 1000C. I copied their schematic and looked at the Application Notes for both the ICs to choose the values I wanted. Lets find out if this works(if I can even solder it lol).