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https://github.com/killerjulian/node-anemometer

Measuring the wind speed with an anemometer
https://github.com/killerjulian/node-anemometer

anemometer pcf8583 raspberry-pi

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Measuring the wind speed with an anemometer

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README 

        
# node-anemometer



[![NPM](https://nodei.co/npm/node-anemometer.png)](https://npmjs.org/package/node-anemometer)



## Install



```

npm install node-anemometer

```



```

yarn add node-anemometer

```



## Required hardware



**At the moment this library can only be used with an extra counter module [PCF8583](https://www.nxp.com/docs/en/data-sheet/PCF8583.pdf)**



### The circuit board



There are several ways to count the revolutions of the anemometer. The best result I got with the KY-003 board (a magnetic field sensor) and a magnet. The magnet is placed so that it triggers the sensor with each complete rotation. If you use mechanical components like reed switches, you need a debounce filter and additional hardware to avoid count many [noise values](https://ptvo.info/zigbee-configurable-firmware-features/external-sensors/pcf8583-zigbee-counter/). There are many designs of such PCBs. Here is one example: [circuit board from Horter](https://www.horter.de/doku/i2c-counter-PCF8583_db.pdf)



## System settings



[Configuring I2C on the Raspberry Pi](https://github.com/fivdi/i2c-bus/blob/HEAD/doc/raspberry-pi-i2c.md)



[Creating Multiple I2C Ports](https://www-laub--home-de.translate.goog/wiki/Raspberry_Pi_multiple_I2C_bus?_x_tr_sl=de&_x_tr_tl=en&_x_tr_hl=de&_x_tr_pto=wapp) (_for advanced people_)



## Usage



Example in TypeScript (with ES Modules):



_Examples in the calculation not adjusted to your anemometer_



```typescript

import { Anemometer, calcFactor, WindSpeed, WindSpeedUnits } from '../../dist';



const calc = (pulses: number, time: number): WindSpeed => {

  // You cannot divide by 0

  if (time <= 0) {

    return new WindSpeed(0, WindSpeedUnits.kilometersPerHour);

  }



  // More about the calculation can you find in the readme file

  const windSpeed = (pulses / 2 / time) * calcFactor(9, 1.18);



  // You must always return a class of the type WindSpeed

  return new WindSpeed(windSpeed, WindSpeedUnits.kilometersPerHour);

};



// Initialize the class for your anemometer.

// Never initialize two classes for the same address on the same bus!

// For more options on initializing the class, read the documentation

const myAnemometer = new Anemometer(calc);



async function start() {

  // Establish an i2c connection to the PCF8583 and start the reading process

  await myAnemometer.open();



  // Wait 15 seconds to have a usable average value

  setTimeout(() => {

    // '.getData()' calculates the average wind speed of the past x seconds

    const data = myAnemometer.getData(10);



    console.log(`Wind speed: ${data.rounded(2)} ${data.unit}`);



    // Herewith you can stop the reading process and close the i2c connection

    myAnemometer.close();

  }, 15000);

}



start();

```



You can find more information in the full [documentation 📖](https://killerjulian.github.io/node-anemometer/).



### Calculation



The wind speed is always calculated with the signals and the time. Often you can find information about this in the data sheet. If you can't find any, I will now describe how the calculation works.



The following basic equation applies:



![calculation](./images/calculation.svg)



**`pulses`**: Signals emitted by the anemometer. The are similar when you press a button



**`pulses per rotation`**: Is the number of signals that are output for a complete rotation



**`time`**: Is the duration (in seconds) in which the measurement was performed



**`anemometer factor`**: Mostly to find in the datasheet, but can also be calculated by yourself. More information below



![](./images/pulses.svg)



### Calculate anemometor factor



The `.calcFactor()` function computes the multiplier for the calculation of the wind speed in km/h. The radius (measured distance from the center to the edge of one of the cups) in cm and the anemometer factor. The anemometer factor is a value to compensate for the lost wind energy when turning the arms. In my case this value is `1.18`.



![](./images/anemometer.svg)



---



## Useful information and references



**👉 Special thanks to [@DasMelone](https://github.com/DasMelone) who helped me to work out this project**



- 🌟 [Measuring wind speed using Raspberry Pi](https://projects.raspberrypi.org/en/projects/build-your-own-weather-station/5)

- 🌟 [Why a debounce filter?](https://ptvo.info/zigbee-configurable-firmware-features/external-sensors/pcf8583-zigbee-counter/)

- 🌟 🇩🇪 [Setting multiple i2c buses on the Raspberry Pi](https://www.laub-home.de/wiki/Raspberry_Pi_multiple_I2C_bus)

- 🇩🇪 [Video of the calculation with an Arduino](https://www.youtube.com/watch?v=Mr05UumeQsk)

- 🇩🇪 [I2C pulse counter module by Horter](https://www.nikolaus-lueneburg.de/2019/05/i2c-impuls-counter-modul/)

- [Counting events with Arduino and PCF8583](https://tinkerman.cat/post/counting-events-with-arduino-and-pcf8583/)

- [Low Power Counters](https://hackaday.io/project/174898-esp-now-weather-station/log/184063-low-power-counters)

- [What is a Schmitt trigger?](https://en.wikipedia.org/wiki/Schmitt_trigger)

- [Datasheet anemometer](https://www.argentdata.com/files/80422_datasheet.pdf)

- [Datasheet PCF8583](https://www.nxp.com/docs/en/data-sheet/PCF8583.pdf)

- [Datasheet 74HC132](https://assets.nexperia.com/documents/data-sheet/74HC_HCT132.pdf)



_🌟 - I recommend to read this_



_🇩🇪 - Content that is only available in German_



---



## Author



👤 **KillerJulian **



- Github: [@KillerJulian](https://github.com/KillerJulian)



## 🤝 Contributing



Contributions, issues and feature requests are welcome!
Feel free to check the [issues page](https://github.com/KillerJulian/node-anemometer/issues). You can also take a look at the [contributing guide](https://github.com/KillerJulian/node-anemometer/blob/master/CONTRIBUTING.md).