AP

WiFi should be using 20 MHz bandwidth.

Flash multiple devices

esphome -s devicename livingroom -s upper_devicename Livingroom run --device 10.0.50.81 d1_bme280.yml
esphome -s devicename bedroom -s upper_devicename Bedroom run --device 10.0.50.84 d1_bme280.yml
esphome -s devicename hallway -s upper_devicename Hallway run --device 10.0.50.85 d1_bme280.yml

Secrets

secrets.yaml

---

wifi_ssid: ""
wifi_password: ""