# 3.33 Compass

## 3.33.1 Overview

The AK8975 module is adopted to read direction values. According to these values, the OLED displays different arrows.

## 3.33.2 Test Code

### 3.33.2.1 Code Flow

![6-33-2-1](./media/6-33-2-1.png)

### 3.33.2.2 Build Code

There are two ways to upload the code: directly open the code file we provide; or manually build blocks.

**Directly open the code file we provide:**

1. Click ![](./media/j68.png) and choose `Load from your computer`

![](./media/j67.png)

2. We have already downloaded the codes on computer desktop, so open the file and choose `3-33-compass.sb3`

**Manually build blocks:**

1. Build the two basic blocks:![6-1-4-1-1](./media/6-1-4-1-1.png)
2. Initialize AK8975 module and OLED display, declare a variable “direction”.

![](./media/6-33-2-2-1.png)

3. Clear the OLED, and assign the direction value of AK8975 to the variable *direction*

![](./media/6-33-2-2-2.png)

4. Add a ![j25](./media/j25.png) to determine whether 340 < direction < 360. If yes, OLED shows “↑”.

   Block condition: direction > 340 and direction < 360

![](./media/6-33-2-2-3.png)

5. Duplicate blocks and determine whether direction > 230 and direction < 250. If yes, OLED shows “→”.
6. If direction > 140 and direction < 170, OLED shows “↓”.
7. If direction > 70 and direction < 90, OLED shows “←”.

![](./media/6-33-2-2-4.png)

8. Add an OLED refresh block and add a delay of 0.5S.

**Complete Test Code**

![6-33-2-2](./media/6-33-2-2.png)

### 3.33.2.3 Test Result

After uploading code, the arrow on the OLED will nearly point to the South. Move the coding box and you will see the direction changes.