PCB

In the process of designing the PCB, there have been some key features for the project. One of those key features was making important pins for the microcontroller accessible such as swdclk, and swdio. These pins are used for compiling the microcontroller . If these pins had no access, the device could not be compiled therefore it would not work. Like swdclk and swdio pins, the device should have accessible Vdd and ground pins, for compiling the code and for powering the device at daily usage. For this device compile pins (Vdd, ground, swdclk, and swdio pins) and power pins (Vdd and ground pins) have been placed separately on the PCB. This is because of the placement of the coin cell battery holder. Coin cell battery holder has been placed at the top of the PCB for the user to access it more easily and change the battery when it dries out, and compile pins have been placed at the bottom of the PCB for a more compact look and easy access while compiling the code into the PCB.

One of the key points while designing a PCB is that in wiring stage connecting the components with copper lines 90 degrees angles had to be avoided and instead 45 degrees of two turns have been used .The reason for avoiding 90 degrees turns is that sharp turns are difficult to keep the line width stable and differences in the width of the trace can affect the voltage level getting across the line. At the manufacturing stage, it has been more difficult for the factories to produce a long trace with a low width level and for that long traces are supported with a high width level in case of a trace detach.

It is aimed to make the most space-effective antenna for the PCB. As an antenna embedded antenna has been chosen because of its compact design and effectiveness. Embedded antennas are not effective at long-range transmissions but for the purpose of the device, only shorth range transmissions are expected. The downside of these types of antennas is that they get affected from the noise of the components. To prevent this from happening, a ground charged area has been placed between components and the embedded antenna.