You’ll then use that new Board Manager to import the ESP32 boards and software examples. In order to work with ESP32 boards in the Arduino IDE, you are going to need to add a new Board Manager into the IDE. This library duplicates the functionality of the original Arduino Servo library while adding a few extra features of its own. I’ve chosen to use the ESP32Servo Library by Kevin Harrington. There are many servo motor control libraries available for the ESP32, many of which emulate the Arduino Servo library while adding new functionality. Unfortunately, it won’t work with the ESP32. The Arduino IDE comes with a built-in servo motor control library, which is appropriately named “Servo”. So when selecting a PWM pin to use with your servo motor you’ll want to be sure that you don’t need one of the pins other functions in your design.Įven with that slight restriction, there are still several PWM pins available to drive servo motors, LEDs, and many other devices. One thing to note about the ESP32, however, is that many of the GPIO pins have multiple functions. In fact, the ESP32 has the capability of controlling 16 PWM outputs independently. Most microcontrollers can be used to generate PWM signals and the ESP32 is certainly no exception. If you’d like a more detailed overview of servo motor operation check out the article Using Servo Motors with the Arduino. The pulse is continually applied to the control lead on the motor, locking the shaft into the desired position. Within that period the pulse width is varied, a shorter pulse positions the servo towards the zero-degree mark while a longer one moves the motor shaft towards the 180 (or 270) degree position. The PWM signal is usually about 50Hz, which is a period of 20ms. Servo PositioningĪnalog servo motors use PWM, or Pulse Width Modulation, to control the motor shaft position. You can use jumper wires to connect this to a solderless breadboard. Most servo motor cables terminate in a 3-pin Dupont female connector. On some servo motors, this is a Black wire. Generally 5-6 volts DC, but be sure to check first. Red – The servo motor power supply input.Some models, especially 270-degree rotation servos, use a White wire for this connection. This is a logic-level signal, and most servo motors can accept 3.3-volt logic as well as 5-volt logic. Although the color-coding is not an official standard many manufacturers use the same colored wires: Most analog servo motors like the SG90 use a 3-wire color-coded cable for interfacing. The SG90, like most servo motors, can be powered from 5-6 volts, so servo motors are great for battery-powered applications. It has a “cousin”, the MG90, which has similar specifications but uses metal gears. It’s a small plastic-gear servo that has become a standard for experimenting and is also used in a lot of RC hobby applications. The inexpensive servos we use for hobbyist applications are usually analog servo motors, which are the types we will be using today.Ī very common and inexpensive servo motor is the SG90. Servo motors come in a wide range of sizes and can be controlled either with an analog PWM signal or with a digital I/O signal. There are specially modified servo motors that can rotate beyond 360-degrees, but we won’t be working with those today. Most servos are limited in rotation to either 180 or 270 degrees, with 180-degree servo motors being more common. A high gear ratio allows a small servo to have an impressive torque rating. Servo motors are geared DC motors that have an integrated servomechanism with a feedback loop to allow precise positioning of the motor shaft. Built-in WiFi and Bluetooth open the door to all sorts of remote control possibilities. The latter reason is why many people choose the ESP32 over an Arduino for controlling servo motors. It has built-in WiFi and Bluetooth capabilities.It has a lot of PWM output pins, so it can drive several servo motors.The ESP32 has I/O pins that can be used as touch switches.There are built-in sensors in the ESP32, including a hall-effect sensor.The ESP32 has analog outputs as well as analog inputs.The ESP32 has a wealth of I/O ports, more than most Arduino’s.So why use an ESP32, especially as most Arduino’s are less expensive? Depending upon your application there may be no reason, or there may be several. Arduino’s, for example, have no problem controlling servos and the Arduino IDE even comes with a built-in servo motor library and a few bits of sample code to get you started. Servos & ESP32Ĭontrolling an analog servo motor, which is the type of servo motors most commonly used by hobbyists, is a task that most microcontrollers have no problem performing. As you’ll soon see, controlling a servo motor with the ESP32 is quite similar to using an Arduino, with the added advantage of the ESP32’s wealth of ports and capabilities.
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