# Servo SG90 (180° / 360°)

![pic_70](images/servo/servo_intro.jpg)
## Introduction
The SG90 servo motor is a tiny and lightweight motor which can perform different angle adjustment (180° servo) or rotation control (360° servo).
<P>


## The principle
The Servo motor operate base on the PWM signal, the action of servo motor will following the input signal's duty cycle.<BR>
The SG90 designed duty cycle (pulse length) is 500µs to 2500µs, during this range, the duty cycle will be representing different meaning.
![pic_90](images/servo/servo_pwm.png)

<HR>

### 180° Servo

For 180° Servo, the duty cycle will represent to the position<BR>

|Duty cycle(us)|Degree|
|--|--|
|500|0°|
|833|30°|
|1166|60°|
|1500|90°|
|1832|120°|
|2165|150°|
|2500|180°|

![pic_70](images/servo/180servoMove.gif)

<HR>

### 360° Servo

For 360° Servo, the duty cycle range is different, and the meaning represent to direction and speed<BR>

|Duty cycle(us)|Direction|Speed|
|--|--|--|
|1000|clockwise|100%|
|1166|clockwise|60%|
|1333|clockwise|30%|
|1500|N/A|stop|
|1666|anti-clockwise|30%|
|1832|anti-clockwise|60%|
|2000|anti-clockwise|100%|

![pic_50](images/servo/360servoMove.gif)


## Specification
* Operating voltage: 4.8V (~5V) 
* Weight: 9g
* Operating speed: 0.1 sec / 60 degree
* Stall torque: 1.8 kgfcm
* Interface: PWM signal
* PWM period: 20ms(50Hz)
* Duty cycle: 500µs ~ 2400µs 
* Operation degree: 0~180° (180° Servo) / N/A (360° Servo)
* Temperature range: 0 ~ 55°C 


## Pinout Diagram

|Pin|Function|
|--|--|
|G|Ground|
|V|Voltage Supply|
|S|Input (PWM signal with duty cycle)|

## Outlook and Dimension
![pic_100](images/servo/servo_dim.png)

Size: 32mm\*12mm\*32mm

## Determine the type of servo (180°/360°)
Look at the side that have cable pull out, checking there have a variable resistor or not. <P>
If have "green variable resistor", that is 180° servo.

![pic_50](images/servo/servo_180.jpg)

 Otherwise, that is 360° servo.

![pic_50](images/servo/servo_360.jpg)



## Quick to Start/Sample

* Connect the sensor to development board (direct plugin or using wire)
![auto_fit](images/servo/servo_connect.png)<P>

* Open Makecode, using the [https://github.com/smarthon/pxt-smarthome](https://github.com/smarthon/pxt-smarthome) PXT <P>
![auto_fit](images/button/button_pxt.png)<P>

<H3>The extension contain two functions that provide convenience to set the specific position or rotation.</H3><P>

For 180° Servo, you may control that turn to specific degree position

* Use the `Turn 180° Servo to 135 degree at P1` to make it to turn to 135° position
![auto_fit](images/servo/servo_180_1.png)


For 360° Servo, you may control that turning in specific direction and the rotation speed

* Use the `Turn 360° Servo with clockwise direction speed Level 3 at P1` to make it rotate at max speed and clockwise direction.
![auto_fit](images/servo/servo_360_1.png)

## Result
If you using 180° servo with the corresponding program, after the button A is pressed, the servo will turn to the 135° position.
![pic_90](images/servo/servo_result_1.jpg)

If you using 360° servo with the corresponding program, after the button B is pressed, the servo will keep rotate in clockwise direction with max speed.
![auto_fit](images/servo/servo_result_2.gif)


## Datasheet
[SG90](https://content.instructables.com/ORIG/FA2/O1SS/J7ARLNBW/FA2O1SSJ7ARLNBW.pdf)