SG90 Servo

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In many computers the current is not enough to drive the servo!!!

If it does not work, keeps disconnecting, or rebooting the ESP the power is not sufficent and you need a capacitor ot an extra power supply.

See the last section below (SG90 Servo#Power Issues) and the video for details how to do this.

Schematic - Connecting the SG90[edit]



Code Examples ESP8266[edit]

Basic control[edit]

Assuming the servo is connected to Pin 5.

 1 from machine import Pin,PWM
 2 from time import sleep
 4 servoPin = Pin(5, Pin.OUT)
 5 pwm =  PWM(servoPin, freq=50)
 6 pwm.deinit() # workaround to reset PWM
 7 pwm = PWM(servoPin, freq=50)
 9 val = 50
11 while True:
12   pwm.duty(val)
13   val = val + 1
14   if val>100:
15     val = 50
16   print(val)
17   sleep(0.05)

Controlling the servo with a Poti[edit]

A0 is the analog input with 10 bit resolution. It reads the analog value every second and print it to the console and sets the servo based on the analog input.

 1 from machine import Pin, ADC, PWM
 2 from time import sleep
 4 analogPin = ADC(0)
 5 servoPin = Pin(5, Pin.OUT)
 6 pwm =  PWM(servoPin, freq=50)
 7 pwm.deinit()
 8 pwm = PWM(servoPin, freq=50)
10 while True:
11   analogVal =
12   pwm.duty(int(analogVal/10))
13   print(analogVal)
14   sleep(1)

Related Tutorial Videos[edit]

PWM Output: connecting a servo and and LED[edit]

Power Issues[edit]

When connecting the servo to the ESP32 or ESP8266 it may not work at all, may restart at random times, or may move to a wrong angle. This is typically a power issue. The ESP-board is and the USB-output of the computer does not provide enough power. There are two fixes: adding a big capacitor (e.g. electrolytic capacitor Elko 2000 uF) or adding an external power source (e.g. USB-Power). The external power source is the better solution.

Have a look at the video for details.

Adding a Capacitor[edit]


Connecting an external Power Source[edit]

PowerUSB.JPG PowerUSB-module.JPG