RANLWE01 -- Rain Gauge (LoRaWAN)
Product Description
The Aqua-Scope rain gauge with LoRaWAN Class A connectivity measures precipitation using a tipping bucket mechanism with an accuracy of 0.5 mm water column at 15-minute intervals, as well as temperature. A heavy rain alarm is triggered immediately when the value exceeds 15 l/h (configurable).
The system is fully open source (available at github.com/aqua-scope/lorain).
Key Features:
- Tipping bucket principle, 0.5 mm resolution
- Heavy rain alarm at > 15 l/h (configurable)
- LoRaWAN Class A (EU868)
- 2 x AAA batteries (VARTA, approx. 2 years lifespan)
- Automatic network connection and reconnection
- Low battery warning via radio
- Protection rating: IP55
Starting and Placement
- Open the dome by turning counterclockwise.
- Remove the electronics box via two clip mechanisms.
- Insert two AAA batteries -- the LoRaWAN connection attempt starts immediately.
- Red/green LED indicates the JOIN process.
- The button can be operated with a screwdriver or paperclip.
- Reinsert the electronics box.
- Place the sensor on a level surface -- use the spirit level (sight glass) in the base for alignment.
- Secure with three wood screws and wall plugs (prevents wind damage).
See LoRaWAN Connection for network setup.
Incorrect alignment leads to inaccurate or missing measurements. Use the built-in spirit level in the base.
Rapid, consecutive button presses may cause duty cycle restrictions to delay transmission.
Sensor Values
Measurement Behavior:
- Every 15 minutes, the corresponding rainfall amount is transmitted (when it is raining)
- Every 6 hours, a zero reading if no rain was detected
- Temperature is included in all messages (rough estimate from uncalibrated NTC sensor)
- Resolution: minimum 0.5 mm water column
- Measurement is only accurate at the sensor location (adjacent areas vary)
- Heavy rain alarm is sent immediately when the threshold is exceeded
Threshold: Default 15 l/h (configurable via parameter 3)
General Information on Rainfall Measurement
- Measurement units: Millimeters of water column OR liters per square meter (1 l/m2 = 1 mm)
- Snow: 1 mm water column corresponds to approx. 1 cm snow depth
- Professional standard: 200+ mm opening (GB/T 21978.2-2014)
- This sensor: 130 mm opening -- smaller footprint, sufficient accuracy
LoRaWAN Communication
See LoRaWAN Connection for setup, keys, JOIN/Rejoin, and the complete Daisychain Protocol.
Supported Sensor Types
| ID | Sensor | Unit | Description |
|---|---|---|---|
0x01 | Temperature | 1/10 °C | Uncalibrated NTC sensor (two's complement) |
0x03 | Operating Time | Days | Since last restart |
0x81 | Rainfall | 0.5 mm steps | Tipping events since last report |
Alarm Types
| ID | Alarm | Value |
|---|---|---|
| 3 (0x03) | Heavy Rain | Current rainfall amount |
| 12 (0x0c) | Low Battery | -- |
Configuration Parameters
| No. | Parameter | Default | Description |
|---|---|---|---|
| 2 | Heartbeat Interval | 24 | Measurement cycles before mandatory report (24 x 15 min = 6 h) |
| 3 | Heavy Rain Threshold | 120 | Seconds per 0.5 mm (120 = 15 l/h) |
| 4 | Measurement Interval | 900 | Seconds (= 15 min), range: 10--60000 |
| 5 | Temperature Calibration | 100 | Linear correction value |
Scope of Delivery
- Rain gauge (main unit)
- 3 x mounting screws + wall plugs
- 2 x AAA batteries (VARTA)
Technical Specifications
| Parameter | Value |
|---|---|
| SKU | RANLWE01 |
| Platform | STM32WLE5CCU6 in RAK 3172 module |
| LoRa | P2P, SF9, Coding 4/5 |
| LoRaWAN | EU868, range > 2 km at 22 dB |
| Rain Resolution | 0.5 mm / 0.5 l/m3 |
| Measurement Period | 15 minutes |
| Temperature Accuracy | +/- 3 °C |
| Temperature Range | -25 °C to +50 °C |
| Status Report | Every 6 hours (when no rain) |
| Heavy Rain Alarm | From 15 l/h (configurable) |
| Controls | 3-color LED, single button |
| Batteries | 2 x AAA, 2.2--3.6 V |
| Protection Rating | IP55 |
| Operating Temperature | -20 °C to +50 °C |
| Storage/Transport Temperature | -65 °C to +125 °C |
| Relative Humidity | 0--90 % |
| Dimensions (device) | 132 x 132 x 139 mm |
| Dimensions (packaging) | 140 x 140 x 150 mm |
| Weight | 219 g |
| Radio Emissions (LoRa) | 868--869 MHz, 4 dBm (2.5 mW) |