Cat Napping

{Introduction }

Lychee the cat loves the sun and wants to know if your home has a good sunbathing spot. Are you up for the challenge?

{Setting logging to false on start}

First, we want to make sure we know when our micro:bit is collecting data. To do this, let’s create a boolean variable and use it to track when the micro:bit is logging data. We’ll start with the logging variable set to false.

► In the ||variables:Variables|| category, click on Make a Variable... and make a variable named logging.
► From the ||variables:Variables|| category, grab the ||variables:set [logging] to [0]|| block and snap it into the empty ||basic:on start|| container.
► From the ||logic:Logic|| category, grab a ||logic:<false>|| argument and snap it in to replace the ||variables:[0]|| value in your ||variables:set [logging] to [0]|| statement.

let logging = false
logging = false

{Toggle logging on A press}

Let’s give Lychee some control over when she wants to start and stop logging data on the micro:bit.

► From the ||input:Input|| category, grab a ||input:on button [A] pressed|| container and drag it into your workspace. Then, grab a ||variables:set [logging] to [0]|| block from ||variables:Varables|| and snap it inside of your ||input:on button [A] pressed|| container.
► From the ||logic:Logic|| category, grab a ||logic:<not []>|| argument and snap it in to replace the 0 argument. Go back to the ||variables:Variables|| category, grab a ||variables:logging|| variable and snap it in to replace the empty ||logic:<>|| in the ||logic:not <>|| statement.

✋🛑 Take a moment to help Lychee answer the following question: What is happening every time she presses the A button?

let logging = false
input.onButtonPressed(Button.A, function () {
    logging = !(logging)
})

{Visual logging indicators}

It would help to know when the micro:bit is logging data and when it isn’t. For this step, we will be building out a visual indicator using an if then / else statement.

► From the ||logic:Logic|| category, grab an ||logic:if <true> then / else|| statement and snap it in at the bottom of your ||input:on button [A] pressed|| container.
► From ||variables:Variables||, grab a ||variables:logging|| variable and snap it in to replace the ||logic:<true>|| condition in your ||logic:if then / else|| statement.

let logging = false
input.onButtonPressed(Button.A, function () {
    logging = !(logging)
    if (logging) {
    } else {
    }
})

{Set the indicator icon}

► Let’s display an image when the micro:bit is logging data. From the ||basic:Basic|| category, grab a ||basic:show icon [ ]|| block and snap it into the empty top container of your ||logic:if then / else|| statement.
► Set it to show the “target” icon (it looks like an empty sun - scroll down to find it!). This will show whenever your micro:bit is collecting data.
💡 In the show icon dropdown menu options, you can hover to see what each design is called.

let logging = false
input.onButtonPressed(Button.A, function () {
    logging = !(logging)
    if (logging) {
        basic.showIcon(IconNames.Target)
    } else {
    }
})

{Auditory logging indicators}

Let’s now add an auditory indicator that your micro:bit is logging data!

► From the ||music:Music|| category, grab a ||music:play sound [dadadum] [in background]|| block and snap it into the bottom of the top container of your ||logic:if then / else|| statement.
► Click on the [dadadum] dropdown and select nyan, then set the playback mode to ||music:[until done]||. Your block should now say ||music:play melody [nyan] [until done]||.

let logging = false
input.onButtonPressed(Button.A, function () {
    logging = !(logging)
    if (logging) {
        basic.showIcon(IconNames.Target)
        music.play(music.builtInPlayableMelody(Melodies.Nyan), music.PlaybackMode.UntilDone)
    } else {
    }
})

{Logging off indicator}

► Let’s clear the board when the micro:bit is not logging data. From the ||basic:Basic|| category, grab a ||basic:clear screen|| block and snap it into the empty bottom container of your ||logic:if then / else|| statement.

let logging = false
input.onButtonPressed(Button.A, function () {
    logging = !(logging)
    if (logging) {
        basic.showIcon(IconNames.Target)
        music.play(music.builtInPlayableMelody(Melodies.Nyan), music.PlaybackMode.UntilDone)
    } else {
        basic.clearScreen()
    }
})

{Time interval for data logging}

Let’s set up the data logging for Lychee! In order to get Lychee a good amount of data without running out of memory, we should collect one data point for her every minute.

► From the ||loops:Loops|| category, grab a ||loops:every [500] ms|| container and add it to your workspace.
► Click on the the 500 dropdown and select 1 minute.
💡 1 minute is equivalent to 60000ms, which is what the number will automatically change to.

loops.everyInterval(60000, function () {
})

{Setting up a logging variable}

Now, let’s use an if then statement to track when the micro:bit is logging data.

► From the ||logic:Logic|| category, grab a ||logic:if <true> then|| statement and snap it into your ||loops:every [600000] ms|| container.
► From the ||variables:Variables|| category, drag out a ||variables:logging|| variable and snap it in to replace the ||logic:<true>|| argument in the ||logic:if <true> then|| statement.

let logging = false
loops.everyInterval(60000, function () {
    if (logging) {
    }
})

{Setting up logging - Part 1}

Lychee loves her sun spots because they provide a nice, sunny and warm place to nap. So, we’ll need to measure the temperature and light in different places around the house.

► From the ||datalogger:Data Logger|| category, grab a ||datalogger:log data [column [""] value [0]] +|| block and snap it inside the ||logic:if [logging] then|| statement.
► Click on the "" after the word column and type in “temp“.
► From the ||input:Input|| category, select the ||input:temperature (°C)|| parameter and drag it in to replace the 0 after the word value.

let logging = false
loops.everyInterval(60000, function () {
    if (logging) {
        //@highlight
        datalogger.log(
            datalogger.createCV("temp", input.temperature())
        )
    }
})

{Setting up logging - Part 2}

► On the right of the ||input:temperature (°C)|| input that you just snapped in, there is a ➕ button. Click on it. You should now see a new row that says ||datalogger:column [""] value [0]||.
► Click on the empty "" after the word column and type in “light“.
► From the ||input:Input|| category, select the ||input:light level|| parameter and drag it in to replace the 0 parameter after the word value.

let logging = false
loops.everyInterval(60000, function () {
    if (logging) {
        //@highlight
        datalogger.log(
            datalogger.createCV("temp", input.temperature()),
            datalogger.createCV("light", input.lightLevel())
        )
    }
})

{Time to log data! }

You did it! If you have a micro:bit V2 (the one with the shiny gold logo at the top), download this code and try it out!

► Find a sun spot in your house and press the A button to start logging data - your display should show an icon and play a sound to indicate that you are logging data.
► After some time (we recommend at least an hour), press the A button again to stop logging data - your display should clear to indicate that you are not logging data.

{Reviewing your data }

Now that you have logged some data, plug your micro:bit into a laptop or desktop computer. The micro:bit will appear like a USB drive called MICROBIT. Look in there and you’ll see a file called MY_DATA:

Double-click on MY_DATA to open it in a web browser and you’ll see a table with your data:

{Lychee’s preferences }

Does your home have a good sunbathing spot for Lychee? Compare the light and temperature levels you record for different areas around your house! The sunniest and warmest spots will likely be her favorite ☀️😻

//

datalogger