I’ve always been a bit disappointed with the original rain sensor for HomeMatic, so I decided to explore alternatives. After some research, I stumbled upon the optical rain sensor from Hydreon in the USA. This sensor uses the same principle as those in cars for automatic windshield wipers, which immediately piqued my interest.
1. Key Features of the Optical Rain Sensor
- Detects individual raindrops, providing immediate rain detection.
- Versatile use cases, such as irrigation control or rainfall measurement.
- Adjustable settings for sensitivity and operation modes via DIP switches.
- Operates on 9-30V DC and consumes 15-55 mA depending on the state.
- Built-in relay for up to 24V and 1A, with an operating temperature range of -40°C to +60°C.
2. Cost Breakdown
- Sensor: $59.00 (approx. 58.54 EUR)
- Shipping: $19.90 (approx. 19.90 EUR)
- German VAT: 11.23 EUR
- Credit card transaction fees: 1.02 EUR
- Total: ~70.79 EUR
3. Ordering and Delivery
I ordered the sensor directly from Hydreon’s website using a credit card. Shipping via USPS First Class International took about two weeks, with a significant delay due to customs in Germany. The package arrived in excellent condition, and the sensor itself looked very robust.
4. Initial Impressions
Unboxing the sensor revealed a sturdy design, with a protective dome that should withstand hail. The mounting bracket is more than sufficient for the sensor’s weight. The internal electronics also look well-built, with clean soldering and no signs of inferior components.
5. Installation and Testing
I connected the sensor to a 12V power supply and integrated it with a HomeMatic HM-SwI-3-FM module for testing. While the module doesn’t fit inside the sensor housing, I’ve temporarily placed it in the garage with long cables. The sensor detected rain consistently, even during a heavy downpour shortly after installation.
6. Long-Term Plans
Eventually, I plan to integrate this setup into my outdoor control system, using a single power supply for the sensor, HomeMatic module, and other components. I’ll also need to create a watertight enclosure for everything.
7. Final Thoughts
This sensor has exceeded my expectations so far. Its reliability and robust design make it a great addition to any smart home setup. If you’re looking for a dependable rain sensor, I highly recommend giving this one a try!
If anyone has questions or tips, feel free to share them below. Happy tinkering! 