# 3.13 Fan Module

## 3.13.1 Overview

The motor adopts HR1124S motor control chip that is a single channel H-bridge driver chip used in DC motors. The H-bridge drive uses PMOS and NMOS power tubes with low on-resistance, ensuring lower power loss and longer safe working time. In addition, its standby and static working current are both low, so it is commonly used in toys.

## 3.13.2 Schematic Diagram

![t108](./media/t108.png)

**Motor control logic table:**

| IO18 | IO17 |      motor state      |
| :--: | :--: | :-------------------: |
| HIGH | LOW  |    forward rotate     |
| LOW  | HIGH |    reverse rotate     |
| HIGH | HIGH | stop (a gradual stop) |
| LOW  | LOW  | brake (a brake stop)  |

## 3.13.3 Code Blocks

Blocks in ![](./media/codingBox.png):

1. ![t109](./media/t109.png) is a block included in coding box library. It controls the rotation of the motor in the coding box.

**Motor control logic table for the blocks:**

|  motor state   | value (speed) |
| :------------: | :-----------: |
| forward rotate |     1~100     |
| reverse rotate |    -1~-100    |
| stop rotating  |       0       |

## 3.13.4 Test Code

You can manually build blocks, or directly open the code file we provide: `3-13-Fan.ubp`. If you have any questions about how to open code files or upload code, please back to `1.9 Upload Code`.

**Build code blocks:**

1. In ![](./media/control.png), drag ![](./media/t1.png) and ![](./media/t2.png) to the script area, and stack them together.

![t34](./media/t34.png)

2. In ![](./media/codingBox.png), drag ![t109](./media/t109.png) and put it into![](./media/t2.png).

![t110](./media/t110.png)

3. In ![](./media/control.png), drag ![t4](./media/t4.png) block and set delay to `2000`. And put it under ![t109](./media/t109.png).

![t111](./media/t111.png)

4. Duplicate all ![t109](./media/t109.png) but modify power to `-50`.
5. Duplicate all ![t109](./media/t109.png) again but modify power to `0`.

**Complete code:**

![t112](./media/t112.png)

## 3.13.5 Test Result

Connect the coding box to the MicroBlocks via USB or Bluetooth, and click ![t59](./media/t59.png) to upload the code to the coding box. You will see the fan forward rotates for 2s and then reverses for another 2s. Then it stops rotating for 2 seconds. These actions repeat.