A significantly improved version of SumoBot v1! Concise documentation intended as a project showcase for my portfolio/resume.
Notable Improvements:
- 4-layer PCB with dedicated 9V/5V planes and a solid ground plane to improve return current paths and help reduce EMI
- Decoupling & bulk capacitors placed throughout the board for improved power integrity
- STM32 MCU + STM32CubeMX + C/Cmake Firmware
- Various quality of life additions (e.g. strategy switch, remote start, on/off switch, etc.)
- Compact layout featuring 0402 surface-mount components (ft. dog-bone fanout for motor drivers for space and cost)
With the JLCPCB Stencil: $14.16 (PCB) + $21.69 (Shipping) - $5 (Coupon) = $30.85 + Tax
Without the JLCPCB Stencil: $7 (PCB) + $3.12 (Shipping) - $5 (Coupon) = $5.12 + Tax
I went with the second option and generated a stencil using the LPKF Protolaser.
I would not recommend, especially for a small PCB, because the stencil did not sit flat. Required a few manual adjustments.
Then, a reflow oven was used for SMD components:
And the remaining components were through-hole soldered.
I flipped the polarity of the XT-30 connector on the silkscreen without reverse-polarity protection:
It made a very loud sound when the bulk capacitor blew up. Lesson learned to always double check.
