⚠️ This repository is deprecated and no longer maintained. The recommended alternative is BresserWeatherSensorTTN which provides a much cleaner design (separation between Weather Sensor and TTN code) and allows to share a RFM95W/SX1276 radio transceiver between weather data reception (FSK mode) and TTN communication (LoRaWAN mode). It also provides better power management (ESP32 deep sleep) with fast TTN re-joining after wake-up (by using ESP32 RTC RAM).
Bresser 5-in-1/6-in-1 868 MHz Weather Sensor Radio Receiver based on CC1101, ESP8266/ESP32 and RFM95W - provides data via LoRaWAN to The Things Network
Based on:
- Bresser5in1-CC1101 by Sean Siford
- RadioLib by Jan Gromeš
- MCCI LoRaWAN LMIC library by Thomas Telkamp and Matthijs Kooijman / Terry Moore, MCCI
- Lora-Serialization by Joscha Feth
The Bresser 5-in-1 Weather Stations seem to use two different protocols. Select the appropriate decoder by (un-)commenting #define BRESSER_6_IN_1 in the source code.
| Model | Decoder Function |
|---|---|
| 7002510..12 | decodeBresser5In1Payload() |
| 7002585 | decodeBresser6In1Payload() |
Wiring:
| ESP32 | Misc | CC1101 | RFM95W | |
|---|---|---|---|---|
| Name | Pin# | Func. | ||
| 3V3 | 1 | Vcc | VIN | |
| GND | 2 | GND | GND | |
| GPIO23/MOSI2 | 3 | MOSI | MOSI | |
| GPIO18/SCK2 | 4 | SCK | SCK | |
| GPIO19/MISO2 | 5 | MISO | MISO | |
| GPIO04 | 6 | GDO2 | ||
| GPIO26 | 7 | GDO0 | ||
| GPIO15 | 8 | CS | ||
| GPIO27 | CS | |||
| GPIO21 | G0 | |||
| GPIO33 | G1 | |||
| GPIO25 | G2 | |||
| GPIO32 | RST | |||
| GPIO12 | SENSOR_DECOK[¹] | |||
| GPIO13 | TTN_TXCOMP[²] |
[¹]: SENSOR_DECOK: Weather Sensor Message Decoding o.k.
[²]: TTN_RXCOMP: The Things Network Transmisson Completed
You might want to connect an LED (with a resistor to GND) to those pins.
A buffer capacitor of ~10µF across the supply pins of the RFM95W module is recomended.
Texas Instruments CC1101 Product Page
Note: CC1101 Module Connector Pitch is 2.0mm!!!
Unlike most modules/breakout boards, most (if not all) CC1101 modules sold on common e-commerce platforms have a pitch (distance between pins) of 2.0mm. To connect it to breadboards or jumper wires with 2.54mm/100mil pitch (standard), the following options exist:
- solder wires directly to the module
- use a 2.0mm pin header and make/buy jumper wires with 2.54mm at one end and 2.0mm at the other (e.g. Adafruit Female-Female 2.54 to 2.0mm Jumper Wires)
- use a 2.0mm to 2.54 adapter PCB
Note 2: Make sure to use the 868MHz version!
The LoRa transceiver and antenna must be selected according to the Frequency Plans by Country.
Note:
In a 868MHz LoRaWAN region, the RFM95W could probably can be used to receive the weather sensor data. Thus, the transceiver module would be switched between FSK mode for sensor data reception and LoRaWAN mode for the uplink to The Things Network.
The required antenna depends on the signal path between weather sensor and CC1101 receiver or RFM95W transceiver and LoRaWAN gateway, respectively. Some options are:
- wire antenna
- spring antenna (helical wire coil)
- rubber antenna
See Adafruit Tutorial - Antenna Options for wire antenna lengths and uFL connector soldering.
The Data Alliance website helped to sort out my RF connector confusion:
Applications of MHF Connectors & Cables
The MHF series of RF micro-connectors (mating heights listed below are the maximum):
- MHF1 (also known as MHF) has a Mating Height of 2.5mm
- MHF2 has a Mating Height of 2.1mm
- MHF3 has a Mating Height of 1.6mm
- MHF4 has a Mating Height of 1.2mm
MHF3 connector is compatible with a W.FL connector while MHF2 connector is equivalent of U.FL connector. The MHF4 cable connector is the smallest while MHF1 connector is the largest which is comparable to a U.FL connector.
Personally I prefer the SMA connector over the uFL connector - but be aware of the (usual) male/female connector types and the normal/reverse polarity types. See SMA vs RP-SMA what is the difference? by Digikey.
Note: Depending on your region, both the CC1101 weather sensor receiver and the RFM95W Lora Transceiver might use the same frequency. In this case, please keep some distance (min. ~20cm) between the antennas to avoid overloading of the receiver.
Software for Arduino ESP32/ESP8266: Bresser_WeatherStation_CC1101_TTN.ino
The payload data structure is encoded into bytes using a modified version of Lora-Serialization.
Note: writeRawFloat() is missing in the default Arduino library version!
Note2: writeUint32() has been added to the customized version.
Decode payload (a sequence of bytes) into data structures which are readable/suitable for further processing: paste ttn_decoder.js as "Custom Javascript formatter" to "Payload Formatters" -> "Uplink" on The Things Network Console.
How to receive and decode the payload with an MQTT client - see https://www.thethingsnetwork.org/forum/t/some-clarity-on-mqtt-topics/44226/2
V3 topic:
v3/<ttn app id><at symbol>ttn/devices/<ttn device id>/up
v3 message key field jsonpaths:
<ttn device id> = .end_device_ids.device_id
<ttn app id> = .end_device_ids.application_ids.application_id // (not including the <at symbol>ttn in the topic)
<payload> = .uplink_message.frm_payload
JSON-Path with Uplink-Decoder (see ttn_decoder.js)
.uplink_message.decoded_payload.bytes.<variable>