Ikea KRINGSYNT led string mod

Base for housing esp32-c3 super micro, push button, bc139 transistor to drive led string in the lantern using Home Assistant and esphome

BOM: 

• led string 2m operating on 2AA batteries (you need just leds not the batteries)
• some resistors (1k for the base, “some value” for limit the led string current)
• BC139 transistor 
• standard micro switch / push button , the longer shaft will be better but you can print extension (4mm cylinder with brim available in Prusa slicer shapes) to work around it (standard one will be tricky to push throught lantern and 3d print.
• Esp32-c3 super micro, but

To make it work you should create two 4mm holes in the lantern. One for the led string, other for manually operate the leds.

The wiring is simple. 

• Pin 10 goes to ground through push button.
• Base of the transistor connects to the pin 3 through 1k resistor
• Emmitor connects to ground
• the led string connects to 5v pin using some resistors and to Collector of the transistor

simplified example of esphome yml script.

esphome:
  name: lantern
  platformio_options:
    board_build.flash_mode: dio
    platform_packages:
      - toolchain-riscv32-esp @ 8.4.0+2021r2-patch5
  comment: "Lantern"
esp32:
  board: esp32-c3-devkitm-1
  variant: esp32c3
  framework:
    type: arduino
    version: 2.0.5
    platform_version: 5.2.0
switch:
  - platform: gpio
    pin:
      number: 3
      inverted: FALSE
      mode: OUTPUT
    id: led
    name: "Led"
    restore_mode: ALWAYS_OFF
binary_sensor:
  - platform: gpio
    pin:
      number: 10
      mode: INPUT_PULLUP
      inverted: TRUE
    id: manual
    name: "Manual"
    on_press:
      - switch.toggle: led
    internal: true