CH32V003 blinky wedding card

I needed a super affordable BoM to make an electronic wedding invite. Thanks to a couple of open source projects, and CNLohrs work on the Library, the CH32V003 became a good option. Many thanks to Akshai for sending me a few dev boards and the programmer.

Schematics originally based on Christmas LED ball .

Full schematics and firmware is available on the github repo linked below.

PERSISTENCE OF VISION DISPLAY

Features

• USB C 6 pin connector with TP4057 for charging : 2 LEDs show charging status
• 3.7V battery : Li-ION chosen because the CR2032 (non rechargeable) only go up to 3V, and drop below 2.7 quite easily causing the WS2812-2020 RGB LED to glitch.
• CH32V003 processor : F4P6 variant. easy for hand soldered prototypes.
• 14 LEDs : 0805 SMD LEDs, Pink , Yellow , and White
• 1 RGB LED ; WS2812
• IR Receiver : TSOP38238
• Reed switch for timing the POV display ; replace with an Axxelerometer at the earliest
• footprints for BMP280 ( not tested yet )

Software features

• RGB LED control
• PWM fading of LEDs : controls the MOSFET to adjust brightness of all LEDs together
• IR receiver via interrupt : removed from the final version. I'll bring it back later after I add an IR transmitter. Planning to make some interactive games with this.
• Interrupt wake up and deep sleep.
• Persistence of vision display using 8 LEDs

Author links

• Jithin BP
• CSpark Research

Credits

• Fábio Souza for the CH32v003 layout for the LED christmas ball which served as a starting point for this work.
• [CNLohr] (https://github.com/cnlohr/) for the many examples on ch32v003fun from where I lifted sections for H/W interrupts (for IR), deep sleep mode and wakeup, and PWM. The datasheet was also of much help. :)