Schematic

I started building a schematic for the smartwatch. It is my first time using KiCad, so I watched basic tutorials on YouTube about the interface. The symbols for the sensors and microcontroller are not listed on the basic KiCad symbol list and I had to find them separately on the manufacturer’s page and SnapMagic for free.

How I Built the Schematic

At first, I had no idea on how to connect the raw sensors to the microcontroller because I only worked with sensor modules that had other electrical components on it before. Therefore, I looked through the datasheet and there were example circuits, which I followed. Most sensors use I2C communication and it requires resistors between the serial clock and data lines to the power and a capacitor between ground and power to stabilize the power as well. Then, instead of connecting all the wires, I placed labels in order to make the schematic clean to look at. Before I am finished with the schematic, I ran Electrical Rules Checker and fixed errors that showed up.

Next Step

The next step would be to use the schematic to layout the PCB. I am planning to get a hot plate and solder paste, so that I can solder SMD components onto the PCB by myself. It is a long journey, but I am hoping to finish the project with progress made each day. Comment below if you have any questions!