BBQKees Electronics offers two types of products to interface with the EMS bus: Gateways and interface boards.
Interface boards are only a pure hardware board that translate the EMS bus signal to a UART serial port signal and vice versa. You need to connect a microcontroller to these boards and install or write your own software to interact with the EMS bus.
Gateways are a complete plug and play package that you can connect to the bus via just one cable or two wires and they provide an easy to use web, MQTT or HTTP interface to communicate with your home automation.
EMS interface board
EMS Gateway
Choosing between a Gateway and an interface board
If you want to have all your boiler and thermostat data into your home automation like Home Assistant, Domoticz etc with only one cable and with only minimal configuration, then pick a Gateway. If you like to play around with electronics, solder stuff and mess around with Dupont wires, or you want it a bit cheaper but less nice, you can choose one of the interface boards.
Like mentioned above the interface boards are just a piece of hardware. It comes with no microcontroller or software.
Choosing between Gateway models
At this moment two Gateways models are available:
- Gateway S3 = WiFi only model
- Gateway E32 V2 = WiFi + LAN interface model
Although the hardware is a bit different, all models have the identical feature set in the firmware.
The S3 is the basic EMS Gateway.|
The E32 V2 has, aside from WiFi, a RJ45 Ethernet/LAN port for wired networking.
All models are based on the ESP32 range from Espressif. All three have a large 8MB of PSRAM and 16MB of Flash.
The Gateway S3 is based on the ESP32-S3 microcontroller. The E32 V2 has the ‘regular’ ESP32 because that version still supports hardware Ethernet interfaces. This was stripped out of the ESP32-S3.
All models perform equally. And all have the exact same EMS bus connection and configuration options (Except for the wired networking feature of course).
If you have LAN near the boiler or heat pump the E32 V2 would be the best choice. The LAN connection is rock solid.
If you don’t have LAN available near the boiler or heat pump, but only WiFi, the S3 is a good fit, but the E32 V2 also has the same WiFi performance as the S3.
Before purchase please check if you have WiFi coverage near the boiler or heat pump, or WiFi coverage at the place where you would like to install the Gateway if it is outside of the room of the heat source.
Another consideration is the size of the Gateway. The E32 V2 is double the size of the S3 and S3-LR. If you don’t have a lot of room the E32 V2 may be a bit large.
Feature comparison
Below a comparison of the key features and the differences.
| Feature | S3 | S3-LR | E32 V2 |
| Availability | Available | Discontinued | Available |
| WiFI 2.4 GHz | Yes | Yes (with high gain antenna) | Yes |
| LAN RJ45 | No | No | Yes |
| EMS bus service jack | Yes | Yes | Yes |
| EMS bus screw terminal | Yes | Yes | Yes |
| USB-C programming port | Yes | Yes | Yes |
| External power supply 12V DC | Yes | Yes | Yes |
| Optional DS18B20 sensors | Yes | Yes | Yes |
| Wall mountable | Yes with optional wall mount | Yes with optional wall mount | Yes, screw holes on the rear side |
| Processor architecture | ESP32-S3 | ESP32-S3 | ESP32 |
| RAM memory | 8MB PSRAM | 8MB PSRAM | 8MB PSRAM (firmware uses currently 4MB, but hardware has 8MB). |
| Flash memory storage | 16MB | 16MB | 16MB |
| CE certified | Yes | Yes | Yes |
| Dimensions (excluding external connectors) | L: 90 mm W: 50 mm H: 24 mm | L: 90 mm W: 50 mm H: 24 mm | L: 125 mm W: 85 mm H: 27 mm |
| Enclosure construction | Very strong grey ABS plastic with UL 94 V-0 fire retardant class | Very strong grey ABS plastic with UL 94 V-0 fire retardant class | Very strong white ABS plastic with UL 94 V-0 fire retardant class |