Problem: Have a visual indication from a couple of sensors always visible
Sure, I have them on a Lovelace panel but, I'd like them to be visible without opening a browser or turning on a tablet/phone etc.Solution: D1 mini with a couple of RGB LEDs attached!
In this first integration, the two RGB LED's are mounted in a project box under the IR receiver of my 'Media Centre PC'.
It was powered by a separate 5v USB Phone charger but, as my Media PC only goes to sleep (the IR receiver is USB powered all the time) - let's use that instead.
Here's a brief guide to making your own Home Assistant "Black Box". I've also included the ESPHome yaml at the end.
1. Time to get the Soldering Iron out and package the whole thing on some VERO (Strip-board)
2. Re-Build on VERO-board and test. 
3. Trim VERO board to be as small as possible to fit the inside the case.
4. Using the incoming USB connector, solder the 5V & GND to the back of the cable socket.
5. Hot Glue some foam and secure the D1 Mini to the host board.
6. Drill out and mount the LEDs in some plastic and hot glue to host board.
7. Test again, put everything back together and put back on the shelf...
Now that everything is setup, tested and working you can make your own automation(s) for colour, brightness, etc...
My LEDs switch between Red & Green. Left indicates my home alarm status and the right one shows another binary sensor. However, you can have them show any colour for different states, controlled by your own automations.
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ESPHome Code:
esphome:
name: black_box1
platform: ESP8266
board: d1_mini
wifi:
ssid: !secret ssid
password: !secret wifi_password
# Enable logging
logger:
# Enable Home Assistant API
api:
ota:
light:
- platform: rgb
name: "Left LED"
id: left_led
red: left_red
green: left_green
blue: left_blue
restore_mode: ALWAYS_OFF
- platform: rgb
name: "Right LED"
id: right_led
red: right_red
green: right_green
blue: right_blue
restore_mode: ALWAYS_OFF
output:
- platform: esp8266_pwm
id: left_red
pin: D1
inverted: true
- platform: esp8266_pwm
id: left_green
pin: D2
inverted: true
- platform: esp8266_pwm
id: left_blue
pin: D3
inverted: true
- platform: esp8266_pwm
id: right_red
pin: D5
inverted: true
# frequency: 1hz # -- *** Use to make 'RED' flash when on ***
- platform: esp8266_pwm
id: right_green
pin: D6
inverted: true
- platform: esp8266_pwm
id: right_blue
pin: D7
inverted: true
