BOM Finalization (mostly)

UPS Module

continuing from the last journal, I started off with the Waveshare UPS HAT (B) designed for dual 18650 Li-ion batteries since it has usb output and i2c battery monitoring but it used pogo pins to clip into the RPi for power delivery which wouldn’t work with the K2B, then i switched to the (D) model briefly it used a single 21700 cell but it only outputs ~4A while charging actively and would drop as the battery depletes which would cause problems with my estimated power draw. I settled on the UPS HAT (E) running on 4 21700 Li-ions and had 6A output clearing the draw estimate with a margin so its my final pick. I also realized that all the boards only have one shared USB output port which means I will have to use a USB hub since I cant use that USB port.

Battery sourcing

I literally couldn’t find any listings on Amazon for the right 21700 battery or on AliExpress either… the only place I could find one has them at $9.00 a piece but if I can get this done on time it will still be on sale for ~$6.00 on the 18650 Battery Store (which has more than just 18650s )

OLED wiring (not published/done)

I originally planned to get a USB I2C adapter since the GPIO is unconfirmed :/ but I found the official pinout on their info PDF also confirmed there were the right pins for the OLED I already have (ideaspark SSD1306) that accepts 3.3-5V so no mismatch risk!

Budget

so far the price I have is at about $120 in unpurchased parts ($200 if i didnt own alot of the parts )

Fan

I was going to use a fan I already have but the fan uses 12V which would run horribly on the 5V rail

unresolved stuffs

• mounting material?? ( like plastic PLA boards i have already or 3D printing)
• cable management (idk if its going to be enough of a problem?)
• thats about it