micro:climate Kit Experiment Guide

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Contributors: D___Run___, bboyho
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Experiment 5: Reading the Wind Direction and Speed

Introduction

The winds are a-blowin'! The question is, which direction and how hard? In this experiment you will assemble, hook up and program your weather:bit to read the weather meters --- more specifically, the wind anemometer (wind speed) and directional vane. We will again use the micro:bit's LED array to display the wind speed or the direction.

Parts Needed

You will need the following parts:

  • 1x micro:bit Board (Not Included with Kit)
  • 1x Micro-b USB Cable (Not Included with Kit)
  • 1x weather:bit carrier board
  • 1x Weather Meter

Didn't get the kit? Have no fear! Here are the parts you will need to complete this experiment. You may not need everything though depending on what you have. Add it to your cart, read through the guide, and adjust the cart as necessary.

Weather Meters

Weather Meters

SEN-08942
$76.95
26
micro:bit Board

micro:bit Board

DEV-14208
$14.95
7
SparkFun weather:bit

SparkFun weather:bit

DEV-14214
$15.95
USB Micro-B Cable - 6"

USB Micro-B Cable - 6"

CAB-13244
$1.95
3

Suggested Reading

Introducing the Weather Meter (Anemometer and Vane)

The anemometer on the weather meter is the propeller-looking thing that got lost in a ping-pong ball factory.

Anemometer

It has three cups that catch the wind, which then cause it to spin. As the head spins, a magnet at the center of the hub travels over a reed switch that closes the circuit to the pin that the sensor is connected to for a brief moment. The faster the wind is, the faster the anemometer spins and the faster and more often the reed switch is triggered.

We count the number of times that the reed switch is triggered every second, and we can calculate the wind speed from that (1 click per second is roughly 1.5mph).

We did the hard work on this one in terms of simplifying all of this for you. All you need to know is that an anemometer is a wind-speed sensor.

The wind vane is the arrow-looking thing that spins.

Wind Vane

When the wind blows, it catches the vane, which points in the direction that the wind is coming from. As the vane moves around, it closes a series of switches inside, which produce a different resistance at 16 different locations around the hub. Each direction has a specific value that we have mapped to the cardinal directions once you have it set in the location you want it. While the datasheet lists 16 directional degrees, we have simplified the makeCode extension such that the Wind Direction block will return eight directions (N,NE,E,SE,S,SW,W,NE) as a string. Feel free to modify your own code blocks to return all 16!

Hardware Hookup

To help you out in the assembly of your weather meter we have created this step by step assembly guide.

Weather Meter Hookup Guide

July 20, 2017

How to assemble your very own weather meter!

Note: Once you have assembled your weather meter we highly recommend labeling the two cables for the wind and rain sensors. This will make your life much easier in the long run!

Once you have completed the assembly of the weather meter, find the cable for the wind sensors and plug it into the RJ-11 connector on the weather:bit labeled "wind".

wind

With that you are ready to roll!

Running Your Script

Please open a browser window and navigate to https://makecode.microbit.org/. This should open the MakeCode environment that you used to install the weather:bit extension in.

Code to Note

Code to Note Exp 5

Start Wind Monitoring

The Start Wind Monitoring block starts all of the necessary processes to use the wind sensors that plug into the weather:bit. This block show be placed in the On Start block as it only needs to be called once at the very beginning of the program.

Show Number

The Show Number block displays/scrolls whatever number is placed inside of it across the LED array. We use it to display the wind speed in this example.

Wind Speed

The Wind Speed block is a variable block that returns the calculated wind speed from the anemometer. It is updated every 2 seconds!

Show String

The Show String block is similar to the Show Number block in that it displays/scrolls whatever string that it is passed. In this case we use it to display the wind direction.

Wind Direction

Last but not least, the Wind Direction block is a variable block that returns a string value of a cardinal direction that the wind vane is pointing.

What You Should See

Once you power up the micro:bit, spin the anemometer with your hand or place it in front of a fan. The speed in miles per hour should start to scroll across the LED array. If you press the A button on your micro:bit, it will change the readout to print the direction the vane is pointing as the direction the wind is coming from.

Note: Be sure to set your vane so that N on the micro:bit reading is true north for this reading to be accurate.

Exp5_FinalAssembly

Troubleshooting

  • odd readings --- Make sure your wiring is correct, make sure the correct sensors are plugged into the correct RJ11 jack.

  • What is north? --- The directions produced by the weather:bit are based off of readings from the vane, you have to personally line up the orientation of your vane to north.

  • It still doesn't work --- Drop us a line, we would love to help you figure it out!