MicroPython projects

note: my TTY is /dev/tty.usbserial-0001, on Mac you can find yours with ls /dev/tty.*.

Erase & Flash ESP board

Use esptool to erase and flash the ESP32.

esptool.py -p /dev/tty.usbserial-0001 -c esp32 -b 115200 erase_flash

esptool.py -c esp32 -p /dev/tty.usbserial-0001 -b 115200 write_flash -z 0x1000 esp32spiram-idf4-20210202-v1.14.bin

Download latest version of MicroPython

Letterbox

Create a letterbox/secrets.json using letterbox/secrets.json.example as a template.

Refer to device pinout / schematics diagrams for pin details and update these settings in main.py.

LORA_CS = const(18)
LORA_SCK = const(5)
LORA_MOSI = const(27)
LORA_MISO = const(19)
LORA_IRQ = const(26)
LORA_RST = const(14)
LORA_DATARATE = "SF7BW125"

Transfer files using adafruit-ampy.

ampy -p /dev/tty.usbserial-0001 put letterbox/boot.py
ampy -p /dev/tty.usbserial-0001 put letterbox/main.py
ampy -p /dev/tty.usbserial-0001 put letterbox/ulora.py
ampy -p /dev/tty.usbserial-0001 put letterbox/ulora_encryption.py
ampy -p /dev/tty.usbserial-0001 put letterbox/ttn
ampy -p /dev/tty.usbserial-0001 put letterbox/secrets.json

Watch output

screen /dev/tty.usbserial-0001 115200

Decode payload in The Things Network Console

function Decoder(bytes, port) {
  // Decode an uplink message from a buffer
  // (array) of bytes to an object of fields.
  var decoded = {};

  // Decode bytes to int
  var testShort = (bytes[1] << 8) | bytes[0];

  // Decode int 
  decoded.short = testShort;

  return decoded;
}

Credits

Bridge The Things Network to local MQTT broker

Add to Mosquitto mosquitto.conf

# Bridge to The Things Network
connection bridge-ttn
address us-west.thethings.network:8883
remote_username APP_ID
remote_password ACCESS_KEYS
bridge_cafile /mosquitto/config/certs/ttn-ca.pem
bridge_insecure false
topic # both 0 ttn/ massassauga/devices/

ttn-ca.pem - Credits

Add Home Assistant binary sensor

Add to Home Assistant configuration.yaml

 - platform: mqtt
   unique_id: 01234567-89ab-cdef-0123-456789abcdef
   name: "Letterbox Sensor"
   state_topic: "ttn/letterbox/up"
   value_template: "{{ value_json['payload_fields']['short'] }}"
   payload_on: 1
   payload_off: 0
   off_delay: 10
   icon: "mdi:mailbox"
   force_update: true

gregology / micropython