Wedding Card

| Links: Youtube | Instructions | Github | Webpage

Wedding Card

Low cost wedding invites with a cheap RISC-V microcontroller that has LED POV display, RGB, IR receiver, Li-Ion and charger via USB-C !

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.

Schematics originally based on Christmas LED ball .

Full schematics and firmware is available on my github page.

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

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. :)