TECHNICAL SUPPORT
Published 2026-03-19
Have you also encountered this situation? I want to add aservoto my little invention so that it can rotate, but I’m still confused after watching those complicated control principle videos for a long time. Don't worry, today we will talk about the microcontroller control of the steering gear and explain it in the simplest way.
The steering gear is, to put it bluntly, a very obedient little motor. You tell it which angle to turn to, and it will turn to that position obediently without being lazy. There is a little secret inside it, which is that it is equipped with something called a potentiometer, which is like an angle detector and keeps an eye on the position of the output shaft.
When you give it a command, its internal circuit will compare the current position with the position you requested. If it is not at the place, it will drive the motor to rotate, and stop when it is. The whole process is like directing a blind man to get a cup. You shout "click left" and "click forward" until he touches the cup.
The microcontroller is like a messenger, responsible for translating the angle you want theservoto turn into a language that theservocan understand. This language is called PWM, which is a pulse width modulation signal. Simply put, information is transmitted through the high-level duration of a pulse.
Usually this pulse is sent every 20 milliseconds, and the length of high level determines the angle of rotation of the servo. For example, 1.5 milliseconds corresponds to the middle position, 0.5 milliseconds corresponds to the far left, and 2.5 milliseconds corresponds to the far right. You only need to adjust this time in the program to accurately control the servo.
To play with a servo, you need a few things on hand. The microcontroller is the brain. It is recommended to use this entry-friendly board. There is a lot of information online, and it is easy to find answers to questions. As for servos, small servos like the SG90 are cheap and sturdy, and are most suitable for practicing.
️ Pay special attention to the power supply. When the servo is started, the current is quite large. If the microcontroller is directly used for power supply, it will be easy to restart the board. It is best to use a separate battery to power the servo, or add a large capacitor to stabilize the voltage. The wiring is also simple, just connect the signal line to the microcontroller, and connect the power and ground wires.
Writing a program is actually not as mysterious as you think. For example, it has a convenient way to implement specific functions. For example, by directly using the ready-made Servo library, you can easily run the servo with just three lines of code.
Specifically, the first line of code#
If you want it to rotate, use the .write(90) command to make it rotate to a 90-degree position. If you want to manually generate a PWM signal by yourself, it is actually not difficult. You only need to accurately calculate the time, use and cooperate with each other to achieve the goal. The key point is to accurately control the width of that pulse.
The biggest headache for novices on the road is that the steering gear keeps shaking, as if they have Parkinson's disease. This is most likely caused by the power supply. If the current cannot be supplied, the servo will twitch. First check the power supply and add a large capacitor to the power line. Generally, a capacitor of 470 microfarad or above will be effective.
If it still shakes, the signal line may be interfered with. Don't let the signal wires get tangled with the power wires and keep them as short as possible. It is also possible that the control signal in the program is not stable. Check whether the pulse period is strictly controlled at about 20 milliseconds. If these details are taken care of, the servo will be reliable.
There are many types of servos on the market, and choosing the wrong one means digging a hole for yourself. Let’s look at the torque first. This is an indicator of the strength of the steering gear. The unit is kg·cm. If your project requires turning multiple things, use a servo with as much torque as possible. It is safer to leave some margin.
Let's take a closer look at the size and weight. For small projects, a 9-gram servo is sufficient; if the project is slightly larger, a 20-kg metal servo will be needed. In addition, there are differences between digital servos and analog servos. Digital servos have the advantages of fast response and high accuracy, but they are relatively power-consuming. Choosing a servo is like choosing a tool. Only the right one is the most ideal. Don’t buy cheap servos from other brands, otherwise problems will occur at critical moments, which will cause trouble.
The choice of steering gear needs to be treated with caution and cannot be done blindly. Just like choosing the best tool among many, you need to consider many factors. Don’t choose an off-brand servo just because it’s cheap. After all, quality is the key. Digital servos have fast response and high accuracy, which have obvious advantages in some scenarios that require high accuracy. However, the power consumption feature also needs to be considered when using it. For projects of different sizes, it is necessary to accurately select the appropriate weight and size of the servo according to the actual situation. For small projects, use 9-gram servos, and for large projects, use 20-kilogram metal servos. This can ensure the smooth progress of the entire project and avoid affecting the progress due to servo problems.
Have you ever encountered any weird problems while playing with the servo? Welcome to share your experience in the comment area, and let's discuss solutions together. If you find the article useful, don’t forget to like it and share it with friends who need it!
Update Time：2026-03-19
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