SWS Technical Specification and Questions

 

TECHNICAL QUESTIONS

How does the sonic anemometer work?

SKY houses a sonic anemometer in the top of the device. The SKY measures wind speed and direction based on the time of flight of sonic pulses between pairs of transducers. This allows for a high degree of accuracy especially in variable wind conditions.  For more information see Wikipedia on Sonic Anemometers.

What is the report interval for the wind sensor?

Good question! Wind speed and direction are sampled once per second. This one second reading is broadcast locally, which means within range (up to 300 feet line-of-sight) you will be able to see those rapid updates on a phone, tablet or our dedicated DISPLAY. Additionally, these one second samples are averaged on a configurable schedule (1 min, 5 min, 15 min, etc.) and viewable both locally and remotely via our app and website (or third party apps like WUnderstation from Weather Underground). We are also working on a way to see the more frequent updates remotely. Reporting intervals are a balancing act with power consumption. Each time the device 'wakes up' and reports via WiFi it uses power. So, more frequent intervals = less battery life. And visa versa.

Can I use this on a boat or other moving object?

Absolutely. Although not specifically designed for a boat, they are very portable and will send data to your phone or tablet even if you're not connected to the Internet. And SKY has a built-in compass (magnetometer) so it knows which way it's pointing. Combine that with the GPS in your phone or tablet, and SKY will report both TRUE and APPARENT wind as you move through the water.

How do I store and access data? What if I don't have internet access?

Normally, your smart weather station will collect and send data to our servers. You can access this data through our app or our website, and you can export it in a variety of ways. But your stations will also collect and store data even when they are not connected to the Internet! First, the devices themselves will store several weeks of data if left alone. Then, as soon as you're within range of a station, just start up the app and the data will be pulled in. From there, you can view or export it as usual.

How does the haptic rain sensor work?

SKY uses a patent-pending haptic rain sensor in the top of the device. Using a combination of pressure and capacitance, SKY measures and counts each falling raindrop. Algorithms exclude things that are not rain (like the rumblings of a passing train or Harley). This allows SKY to report the instant rain begins falling, the current intensity, and the total rain accumulation over time.  Accuracy compares to a large tipping bucket, but does not get fouled with leafs or bird crap. 

Does the AIR really detect lightning?

Yup. Pretty cool, huh?  The AIR actually detects cloud-to-ground AND cloud-to-cloud activity. Our sensor detects electrical transmissions from lightning activity up to 40km (approx. 25 miles) away and gives an estimate of distance. Humans can typically sense lightning only up to 25km away. The sensor algorithm is even smart enough to reject man-made signals such as microwave ovens and motors.  That said, it's important to place the AIR away from electrical disturbances for best performance. So ya, AIR can alert you when lightning is approaching way before you can hear or see it.

 

SENSOR SPECS:

 

Lightning Sensor
  • (AMS AS3935)
  • detects cloud-to-cloud and cloud-to-ground lightning strikes up to 40 km (25 miles)
  • estimates strength distance to leading edge of storm
Temperature/Humidity Sensor
  • (Silicon Labs Si7021)
  • air temperature -40° to 85 °C +/- 0.4 °C
  • relative humidity 0 to 100% +/- 4%
  • reports dew point & apparent temperature
Pressure Sensor
  • (Bosch BMP280)
  • atmospheric (barometric) pressure up to 1100 mbar +/- 1 mbar
  • reports both station pressure & mean sea level pressure
Haptic Rain Sensor
  • (WeatherFlow design)
  • detects the instant it starts to rain
  • provides hourly rate & daily accumulation
Sonic Wind Sensor
  • (WeatherFlow design)
  • continuously samples wind speed and direction 0 to 100 mph +/- 0.5 mph
  • calculates one-minute and five-minute average speed, direction & gust
Light Sensor
  • (Silicon Labs Si1132)
  • visible and infrared ambient light 1 to 128 kLUX +/- 100 mLUX
  • UV index (0-11+)
  • reports solar radiation 0 to 1900 W/m2 +/- 5%

Do the devices need to be calibrated?

No. Each sensor will be first pre-calibrated by the sensor manufacturer and then will go through calibration procedure on our production line to ensure accuracy.

How long will the battery last?

Our hardware and firmware engineers have spent months optimizing the smallest of details to ensure efficient low power consumption and each device will ship with long-lasting, primary lithium batteries, which perform better in extreme temperatures than alkaline. According to our power consumption calculations, we expect your batteries to last at least one year under normal usage conditions before needing replacement. Your mileage may vary based on how you configure your station.

Are the batteries replaceable?

Yes. The sealed battery compartment is accessible via the twist-off base. You can replace the batteries with common lithium AA batteries available everywhere. We recommend the Energizer "Ultimate Lithium" batteries or similar. The AIR takes 4 AA batteries. The SKY takes 8 AA batteries. *Subject to change.*

What smart home platform will the devices work with?

We are currently working on integrations with SmartThings, NEST, Apple HomeKit, Amazon Echo, and IFTTT. The IFTTT platform enables integration with thousands of connected devices. We intend to continue to build meaningful integrations with as many smart platforms as make sense.

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