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Finally fixed the bug so heres a temp journal to add in the banner so that it looks cool on the blueprint website aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa

Tried fixing the PCB

After receiving my board I rushed to plug it in but then it wouldn't connect and turned super hot. Later that day I sent it in the KiCad discord and turns out that everything was supposedly fine. A few days later after letting my intrusive thoughts win and letting the board heat up, I revised the schematics again and noticed there's a few errors. First of all I believe that I messed up the ground plane and literally encased the STM32 in 3V3 ring:

Then there's the other error of me not using the right decoupling capacitor values which should be 4.7uF.

Finally another error that completely hinders me from fixing the board is that those components are 0201 and are small and also expensive to manufacture (sorry I've learned my lesson)

I spent the entire day trying to learn how to solder 0201 as I was trying to see if I could connect a capacitor that I took from an old wifi router to the board. I tried doing this by soldering a thin copper wire (taken from a jumper cable) to the end of a capacitor and then that capacitor to ground:

Although my soldering iron kept burning the flux and I had to use nail polish remover to try and clean it because I don't have isopropyl alcohol.

After talking with @Kai Pereira, I realized that I had a lot to improve in terms of cost and component selection and that's my goal for V2, to make it as cheap as possible < 50 USD, and maybe include more features.

All this I plan to do after I finish my heatplate as I want to be able to solder everything by hand.

Rerouted PCB on single side to save costs

I had to reroute everything as the board was too expensive for double sided PCBA. So I decided to reduce the sizes down to 0201 for some components like the decoupling capacitors to try and save space and it worked. I then had enough space to move the battery charging IC to the other layer and I had to remove the JST connector and replaced it with 2 exposed pads on the bottom.

Resized Keep-out zone

I decided to resize the keep-out zone after some advice from my informatics teacher and looking online at the datasheet. It originally says to have a 6.5mm space but I don't have that much space horizontally as I do vertically so the most I could do was 4.3mm.

Before:

After:

Layout and Finish Board

I decided to finish the layout and during, I wanted to add an LED and also the debugging pins as test points on the bottom of the board.

I then started routing all of the GPIO's first, then the clocks and then the power stuff. I used .2mm traces for everything that wasn't power and .4mm traces for power.

I also had to impedance match the antenna so basing it off this datasheet:

I then added the traces and also put stitching vias on the side. I also added the keepout zone and made sure that the ground plane on either side had the right clearance.

After that I finished adding the ground pours and ran DRC to fix the remaining errors and finally got this.

After finishing the board I decided to do some renders in Blender and here are the photos.

Finish Schematic and PCB Routing

I started looking through all of the datasheets of all of the parts that I used to get the reference designs for each of the chips and then started wiring up each component.

I then ended up with this:

I still have to wire out the headers but I'm planning on doing that last after I have all the passive components in place.

Chip Selection and Schematic Start

First I'm starting to define the functionality of the board. I want it to be the size of a Raspberry Pi Pico, and I want it to have Bluetooth support as well as headers for the STM32. I also want a JST connector to charge a 1S LiPo Battery for portability so I need a battery charging IC.

Chip Selection:

• STM32WB55CG
• TPS630701RNMR (Buck-Boost Converter)
• BQ24074 (Battery Charger)

Extras:

• SPI LEDs
• USB LEDs
• Battery JST Connector
• USB-C
• Ceramic Bluetooth Antenna