Bino Pi and Gimble

Updates since 27 AUG 2025

- replaced J8 and J9 (LEFT_ENABLE and RIGHT_ENABLE) with jumpers
- changed SW1 symbol and footprint
- changed USB Micro symbol and footprint
- added ESD protection to micro USB
- replaced boot switch to boot button
- added crystal capacitor calculations
- added grounded mounting holes
- changed all 0402 to 0603 for hand-soldering
- "Do not populate" for J3, J11
- changed J11 pinout for better trace routing
- changed J2 and J4 to horizontal connectors
- finished PCB design
- changed and added numerous printed parts
- ordered and assembled board
- verified built-in LED working
- verified laser circuit working
- verified HSE crystal circuit working

Issues

- AMS1117-5.0 was initially dead; replaced
- USB micro B had two pins shorted; lifted GND pad when trying to remove

Changes to v1.1

- STEP and DIRECTION Test Points pins are incorrect on A1 and A2
- BOOT0 had a 100nF capacitor to GND instead of pull-down resistor; this caused floating issues when programming

To do:

- test pin functions on bluepill as specified:
- end stop interrupts
- UART Tx and Rx from pi 5
- YAW/PITCH motor function
- RIGHT/LEFT motor function
- dual-camera stuff with pi 5

27 AUG 2025

Since last update:

• Added 2 test points: PITCH_STEP, YAW_STEP
• Added comments about STEP pins in schematic
• Changed PITCH_END, LEFT_END, RIGHT_END, LASER, SPARE_IN0, SPARE_IN1, SPARE_OUT0, SPARE_OUT1 pins due to external interrupt needs
• Changed focus motor drive calculations due to Adafruit motors are 1/16 ratio
• Created UART transmit codes
• Tested PWM for PA8 (PITCH_STEP) and PB0 (YAW_STEP); calculated prescaler, period counter, and pulse values
• Calculated estimated max current draw of system
• Updated Bino Pi Reference Sheet, schematic

Future Plans:

Short Term:

• Get timing interrupt to work
• Create 6 sequences for focus motor stepping: 1-phase full step CW & CCW, 2-phase full step CW & CCW, half-step CW & CCW
• Test UART and transmit codes (TX from MCU to Analog Discovery 3 working; need to test RX on MCU)
• Test endstop interrupts
• Test laser output circuit using 2N3904; determine experimental current consumption

Long Term:

• Submit PCB for fabrication
• Adjust bottom assembly mounting for PCBA
• Verify operation of PCBA
• Conduct dual-camera operations with OpenCV in Python

30 JUL 2025

Working on Bino Pi Gimble Control PCB.

Future Plans:

• Submit PCB for fabrication
• Redesign bottom assembly mounting with PCBA
• Verify operation of PCBA for all peripherals
• Enable UART communication between Pi 5 and STM32F103C8T6
• Conduct dual-camera operations with OpenCV in Python