I want to move the MAC address outside the script so that it can be entered after flashing the ESP32.

[kenshinnmt]

My ESPHome setup is working fine, but I’d like to set the MAC address manually after MQTT connection instead of hardcoding it. I’ve tried checking the docs but haven’t had success. Any help would be appreciated. Thanks!

substitutions:
  name: phuccao280
  device_description: "JK-BMS - Bluetooth"
  external_components_source: github://syssi/esphome-jk-bms@main
  mac_address: C8:47:80:16:9D:B7
  protocol_version: JK02_32S

[syssi]

This project uses the ble_client component for BLE connections. This is a ESPHome core component. Long story short: It's super complicated to apply a different MAC address at runtime. What's the reason for looking for dynamic configuration here?

[kenshinnmt]

I'm glad you replied to me so soon. I use the connection to a BMS for some acquaintances of mine, and I often change the BMS. I want to simplify the connection process to the BMS. If it's hardcoded, I'd have to flash the code every time I change it. That's why I want to externalize it, so I can input the MAC address after successfully connecting to HA.

[syssi]

You could do something like this:

substitutions:
  name: jk-bms
  device_description: "Monitor and control a JK-BMS via bluetooth"
  external_components_source: github://syssi/esphome-jk-bms@main
  protocol_version: JK02_24S

globals:
  - id: current_mac
    type: std::string
    initial_value: '"00:00:00:00:00:00"'

esphome:
  name: ${name}
  comment: ${device_description}
  min_version: 2024.6.0
  project:
    name: "syssi.esphome-jk-bms"
    version: 2.2.0

esp32:
  board: wemos_d1_mini32
  framework:
    type: esp-idf

external_components:
  - source: ${external_components_source}
    refresh: 0s

wifi:
  ssid: !secret wifi_ssid
  password: !secret wifi_password

ota:
  platform: esphome
  on_begin:
    then:
      - switch.turn_off: ble_client_switch0
      - logger.log: "BLE connection suspended for OTA update"

logger:
  level: DEBUG
  logs:
    esp32_ble_tracker: INFO
    esp32_ble_client: INFO

# If you don't use Home Assistant please remove this `api` section and uncomment the `mqtt` component!
api:
  reboot_timeout: 0

web_server:

esp32_ble_tracker:
  scan_parameters:
    active: false

ble_client:
  - mac_address: "00:00:00:00:00:00"
    id: client0

jk_bms_ble:
  - ble_client_id: client0
    protocol_version: ${protocol_version}
    throttle: 5s
    id: bms0

binary_sensor:
  - platform: jk_bms_ble
    balancing:
      name: "${name} balancing"
    charging:
      name: "${name} charging"
    discharging:
      name: "${name} discharging"
    heating:
      name: "${name} heating"
    online_status:
      name: "${name} online status"

button:
  - platform: template
    name: "BLE Reconnect"
    id: reconnect_button
    on_press:
      then:
        - ble_client.disconnect:
            id: client0
        - delay: 1s
        - lambda: |-
            std::string new_mac = id(mac_input).state;
            ESP_LOGI("ble", "Reconnecting to: %s", new_mac.c_str());

            if (new_mac.length() != 17) {
              ESP_LOGE("ble", "Invalid MAC format: %s", new_mac.c_str());
              return;
            }

            uint8_t mac_bytes[6];
            bool valid = true;

            for (int i = 0; i < 6; i++) {
              if (i * 3 + 1 >= new_mac.length()) {
                valid = false;
                break;
              }
              std::string byte_str = new_mac.substr(i * 3, 2);
              uint8_t val = 0;
              for (char c : byte_str) {
                val <<= 4;
                if (c >= '0' && c <= '9') {
                  val |= c - '0';
                } else if (c >= 'A' && c <= 'F') {
                  val |= c - 'A' + 10;
                } else if (c >= 'a' && c <= 'f') {
                  val |= c - 'a' + 10;
                } else {
                  valid = false;
                  break;
                }
              }
              if (!valid) break;
              mac_bytes[i] = val;
            }

            if (!valid) {
              ESP_LOGE("ble", "Failed to parse MAC: %s", new_mac.c_str());
              return;
            }

            id(current_mac) = new_mac;
            uint64_t mac_uint64 = 0;
            for (int i = 0; i < 6; i++) {
              mac_uint64 = (mac_uint64 << 8) | mac_bytes[i];
            }
            id(client0).set_address(mac_uint64);

            ESP_LOGI("ble", "MAC updated, attempting connection...");
        - delay: 500ms
        - ble_client.connect:
            id: client0

sensor:
  - platform: jk_bms_ble
    jk_bms_ble_id: bms0
    total_voltage:
      name: "${name} total voltage"
    current:
      name: "${name} current"

switch:
  - platform: ble_client
    ble_client_id: client0
    id: ble_client_switch0
    name: "${name} enable bluetooth connection"

text:
  - platform: template
    name: "BLE Target MAC"
    id: mac_input
    initial_value: "aa:bb:cc:dd:ee:ff"
    mode: text
    entity_category: config
    optimistic: true
    min_length: 17
    max_length: 17
    on_value:
      then:
        - lambda: |-
            ESP_LOGI("ble", "New target MAC entered: %s", x.c_str());

text_sensor:
  - platform: template
    name: "Current BLE MAC"
    id: current_mac_display
    update_interval: 5s
    lambda: |-
      return id(current_mac);

It's not recommended and I don't want to invest additional time to improve the feature. ;-)

[kenshinnmt]

Thanks for taking the time to reply and share the sample code — I really appreciate it. I’ll test it out in my setup and will let you know how it goes. Once again, many thanks!