Connecting SlimmeLezer P1 Reader with ADA P1 Bridge (>1.5.4v) – Guide

This guide is for those who already have a working SlimmeLezer (an ESPHome-based P1/DSMR reader) and want to use the ADA P1 Bridge so that it works not from its own P1 port, but from the raw telegram published over the network by the SlimmeLezer.

The goal is simple:

• SlimmeLezer reads from the electricity meter.

• It serves the raw DSMR telegram over HTTP.

• ADA Bridge polls this URL and processes it just like it would if it came from its own P1 port (JSON, rules, MQTT).

If you follow these steps, you get a stable "P1-port-less" ADA Bridge that works well even when only a SlimmeLezer fits next to the meter.

1) What do you need?

Hardware / network:

1. A working SlimmeLezer with ESPHome firmware (typically an ESP8266 D1 Mini).

2. An ADA P1 Bridge configured on Wi-Fi.

3. Both devices must be on the same local network (same router / Wi-Fi, no guest network, no separate VLAN).

Software:

1. ESPHome (Home Assistant ESPHome addon or standalone).

2. The SlimmeLezer YAML configuration.

2) Full example SlimmeLezer YAML (copy-paste base)

If you don't have a SlimmeLezer yet, or want to unify the current one, this is a well-tested complete config. Put this into ESPHome as a new device and then adjust it to your own values (PIN, board, sensors).

Important: you will also need a secrets.yaml file (shown at the end).

substitutions: device_name: slimmelezer device_description: "DIY P1 module to read your smart meter" esphome: name: ${device_name} comment: "${device_description}" name_add_mac_suffix: false project: name: zuidwijk.slimmelezer version: "1.0" on_boot: then: - if: condition: lambda: return id(has_key); then: - lambda: |- std::string key(id(stored_decryption_key), 32); id(dsmr_instance).set_decryption_key(key); else: - logger.log: level: info format: "Not using decryption key. If you need to set a key use Home Assistant service 'ESPHome: ${device_name}_set_dsmr_key'" esp8266: board: d1_mini restore_from_flash: true wifi: networks: - ssid: !secret wifi_ssid password: !secret wifi_password ap: ssid: ${device_name} ap_timeout: 15s captive_portal: logger: baud_rate: 0 api: services: - service: set_dsmr_key variables: private_key: string then: - logger.log: format: "Setting private key %s. Set to empty string to disable" args: [private_key.c_str()] - globals.set: id: has_key value: !lambda "return private_key.length() == 32;" - lambda: |- if (private_key.length() == 32) private_key.copy(id(stored_decryption_key), 32); id(dsmr_instance).set_decryption_key(private_key); ota: - platform: esphome web_server: port: 80 version: 3 uart: id: p1_uart baud_rate: 115200 rx_pin: D7 rx_buffer_size: 4000 globals: - id: has_key type: bool restore_value: yes initial_value: "false" - id: stored_decryption_key type: char[32] restore_value: yes dsmr: id: dsmr_instance uart_id: p1_uart max_telegram_length: 4000 sensor: - platform: dsmr energy_delivered_lux: name: "Energy Consumed Luxembourg" state_class: total_increasing energy_delivered_tariff1: name: "Energy Consumed Tariff 1" state_class: total_increasing energy_delivered_tariff2: name: "Energy Consumed Tariff 2" state_class: total_increasing energy_returned_lux: name: "Energy Produced Luxembourg" state_class: total_increasing energy_returned_tariff1: name: "Energy Produced Tariff 1" state_class: total_increasing energy_returned_tariff2: name: "Energy Produced Tariff 2" state_class: total_increasing power_delivered: name: "Power Consumed" accuracy_decimals: 3 power_returned: name: "Power Produced" accuracy_decimals: 3 electricity_failures: name: "Electricity Failures" icon: mdi:alert electricity_long_failures: name: "Long Electricity Failures" icon: mdi:alert voltage_l1: name: "Voltage Phase 1" voltage_l2: name: "Voltage Phase 2" voltage_l3: name: "Voltage Phase 3" current_l1: name: "Current Phase 1" current_l2: name: "Current Phase 2" current_l3: name: "Current Phase 3" power_delivered_l1: name: "Power Consumed Phase 1" accuracy_decimals: 3 power_delivered_l2: name: "Power Consumed Phase 2" accuracy_decimals: 3 power_delivered_l3: name: "Power Consumed Phase 3" accuracy_decimals: 3 power_returned_l1: name: "Power Produced Phase 1" accuracy_decimals: 3 power_returned_l2: name: "Power Produced Phase 2" accuracy_decimals: 3 power_returned_l3: name: "Power Produced Phase 3" accuracy_decimals: 3 gas_delivered: name: "Gas Consumed" state_class: total_increasing gas_delivered_be: name: "Gas Consumed Belgium" state_class: total_increasing - platform: uptime name: "SlimmeLezer Uptime" - platform: wifi_signal name: "SlimmeLezer Wi‑Fi Signal" update_interval: 60s text_sensor: - platform: dsmr identification: name: "DSMR Identification" p1_version: name: "DSMR Version" p1_version_be: name: "DSMR Version Belgium" telegram: id: telegram_raw name: "Raw DSMR Telegram" - platform: wifi_info ip_address: name: "SlimmeLezer IP Address" ssid: name: "SlimmeLezer Wi‑Fi SSID" bssid: name: "SlimmeLezer Wi‑Fi BSSID" - platform: version name: "ESPHome Version" hide_timestamp: true

2/A) secrets.yaml

The above config will compile only if a secrets.yaml file is present. At minimum, it must contain:

wifi_ssid: "YOUR_WIFI_NETWORK" wifi_password: "YOUR_WIFI_PASSWORD"

If your P1 port is encrypted (Belgium, Luxembourg, some Dutch meters), the key is not put here, but you set it via Home Assistant service:

• ESPHome: slimmelezer_set_dsmr_key

• private_key: "32 character key"

3) Checking the raw telegram endpoint (URL)

After the SlimmeLezer is online, the web server automatically displays the values of the text sensors.

Important compatibility note: The ADA P1 Bridge can consume not only the "plain" textual DSMR telegram but also if the endpoint returns JSON-encoded data with the telegram under a value key (e.g. {"value":"/...!XXXX"}). In this case, the Bridge automatically extracts and processes the contents of the value field. For SlimmeLezer, this is usually plain text, but if some proxy / HA sensor returns JSON, that will not be a problem either.

The URL of the telegram_raw sensor looks like this:

http://<slimmelezer_ip>/text_sensor/raw_dsmr_telegram

Example:

http://192.168.31.149/text_sensor/raw_dsmr_telegram

What should you see? A complete DSMR telegram that:

• Starts with the / character

• Contains several OBIS lines (1-0:1.8.0(...), 1-0:32.7.0(...), etc.)

• Ends with a !XXXX part (CRC)

If you see this, you can proceed with the Bridge.

4) Switching ADA P1 Bridge to URL telegram mode

The ADA P1 Bridge firmware has a dedicated endpoint for this.

4/A) Save and test the URL at once

POST request to the Bridge:

curl -X POST "http://okosvillanyora.local:8989/tg/test" \ -H "Content-Type: application/json" \ -d '{"url":"http://192.168.31.149/text_sensor/raw_dsmr_telegram"}'

Expected responses:

• {"ok":true,...} → URL saved, Bridge switched to URL mode.

• {"ok":false,"msg":"..."} → error found (see troubleshooting below).

The Bridge saves the URL in internal storage (LittleFS), so it starts with this after reboot.

4/B) Checking status

GET http://okosvillanyora.local:8989/tg/status

Here you see among others:

• using_url: true/false

• url_set: true/false

• url_masked (masked, safely)

5) How does the system work from now on?

• SlimmeLezer reads the electricity meter over P1.

• The Bridge fetches the telegram from the specified URL every 10 seconds.

• The Bridge processes it exactly as if it came directly from a serial P1 port:

  • JSON generation

  • Running rules

  • MQTT publishing

  • Web APIs

6) Troubleshooting (if something doesn’t work at first)

1) ADA says: "does not look like a telegram"

• Open the SlimmeLezer URL in a browser.

• If you don’t get a complete telegram, you are not calling the telegram_raw text_sensor.

2) Encrypted telegram (BE/LU)

• Provide the DSMR key with the HA service (set_dsmr_key).

• Without the key, the telegram will be unreadable and ADA will discard it.

3) Partial telegram / sometimes good, sometimes bad

• Set a large buffer in SlimmeLezer:

uart: rx_buffer_size: 4000 dsmr: max_telegram_length: 4000

4) IP address changes

• It is recommended to assign a fixed IP to SlimmeLezer in the router.

• If it already changed, call /tg/test again with the new address.

5) Bridge and SlimmeLezer cannot see each other

• Do not put them on a guest network.

• Make sure there is no network separation (VLAN) between them.

• Try pinging the SlimmeLezer IP from the network