# Recording and Playback

With the built-in microphone and speaker, simple recording and playback is possible.

KOI can record a 3 second audio clip and saves the file as a wav format.

### Install an SD Card

<figure><img src="https://kittenbothk.readthedocs.io/en/latest/_images/02-12.png" alt=""><figcaption></figcaption></figure>

```
The pictures are stored onto an SD card, without an SD card, these operations would fail.
```

### Recording and playback

<figure><img src="https://kittenbothk-eng.readthedocs.io/en/latest/_images/mcbanner.png" alt=""><figcaption></figcaption></figure>

#### **Loading Extensions**

Search "KOI" in the search bar.

<figure><img src="https://kittenbothk.readthedocs.io/en/latest/_images/koi_search.png" alt=""><figcaption></figcaption></figure>

Or copy and paste the following link to the search bar.

**<https://github.com/KittenBot/pxt-koi>**

Blocks for recording and playback:

<figure><img src="https://kittenbothk.readthedocs.io/en/latest/_images/041.png" alt=""><figcaption></figcaption></figure>

### Sample Program:

{% embed url="<https://makecode.microbit.org/_Tc1EmKJ8eWuR>" %}

### Program Flow

Download the program to Micro:bit.

1. Press button A on the Micro:bit, KOI will record what you say.
2. Press button B on the Micro:bit, KOI will playback the audio file.

### Sample Code

[Recording and playback (Extension0.5.7)](https://makecode.microbit.org/_irkWewakW2Fo)

### Extension Version and Updates

There may be updates to extensions periodically, please refer to the following link to update/downgrade your extension.

[Makecode Extension Update](https://kittenbothk-eng.readthedocs.io/en/latest/Makecode/makecode_extensionUpdate.html)

### FAQ

#### 1: There is no reaction after pressing the buttons on the Micro:bit.

· A: This is because KOI has a longer boot time than Micro:bit. When the power is turned on, Micro:bit has already ran the code for KOI initialization before KOI is ready.

· Solution: Reset your Micro:bit after KOI has been turned on. (The trick is to let KOI power on completely before initialization.)

#### 2: Does KOI work with 3V input?

· A: No, KOI only works with 5V.

#### 3: Can I change the recording duration?

· A: No, because recording duration is limited by the amount of RAM that KOI has.

#### 4: Can I play mp3 files on the KOI?

· A: No, KOI can only play wav files, and file size cannot exceed 512KB.

#### 5: Can I create my own wav files to play on KOI?

· A： Yes but make sure the duration is less than 3.75 seconds with a bitrate of less than 512kbps. The file size has to be within 512KB.