TECHNICAL SUPPORT
Published 2026-03-04
It's really annoying to see yourservospinning all the time. This is usually not because it has "convulsions", but because something is wrong in some link. Don't worry, let's talk today about how to find out and solve this problem step by step like a veteran.
The first reaction of many friends is "Is theservobroken?" In fact, the probability of the servo itself burning out is lower than we thought. The most common situation is that it receives the wrong instructions or the working conditions are wrong, causing it to spin "at a loss".
For example, I met a friend who makes a smart car. His servo always vibrates slightly when it is stationary, and occasionally it will turn on its own. At the end of the investigation, it was found that the power supply was insufficient and the voltage fluctuation caused the servo control board to reset and send an error signal. Therefore, don't rush to sentence the steering gear to "death". We have to go through it from beginning to end like a detective.
To find the "real culprit", you must learn to isolate the problem from its "accomplices." You can do a simple test: give the servo the most basic and simple test program, such as turning it to 0 degrees, stopping for one second, then turning it to 90 degrees, and stopping for one second. If the servo is obedient in this case, the problem probably lies in your complicated final program logic.
On the other hand, if the servo is "drawing" even under the simplest test program, then we have to focus on the circuit and hardware. At this time, you can touch the motor and driver chip of the servo. If it is very hot, it is likely that there is a short circuit in the circuit, or the motor is blocked and the current is too high. Using this "divide and conquer" approach can help you quickly narrow down the scope of your investigation.
This is particularly easy to overlook, but it is crucial. The commonly used analog servos and digital servos have different requirements for control signals. Many entry-level servos, such as analog servos such as SG90, usually require a 50Hz (ie, period 20ms) PWM (pulse width modulation) signal.
If the PWM frequency you set in the program is wrong, for example, set to 200Hz, the circuit inside the servo will not be able to correctly analyze the signal, and it may become confused, manifesting as constant shaking or rotation. Therefore, the first thing you should do when you get the servo is to confirm its specifications, look at the signal frequency and pulse width range it requires (usually 0.5ms to 2.5ms), and then set them accurately in the code.
This is definitely the easiest pitfall for newbies. The steering gear is a "big eater", especially at the moment of starting and loading, it requires a very large current. If your main control board (for example) directly uses its 5V pin to power the servo, once the current demand rises, the voltage will be instantly pulled down.
When the voltage is low, the main control board may be reset, or the servo control logic may be confused, causing it to rotate randomly. The performance is: the rudder has no strength to move, it gets stuck one after another, and it even starts to rotate slowly without you giving any instructions. The solution is simple:prepare a separate external power supply for the servo! Connect the servo's power wire (usually red) and ground wire (brown or black) to the external power supply, and only connect the signal wire (usually yellow or orange) to the main control board. In this way, the main control board and the servo do their own thing without interfering with each other, and the problem is usually solved.
Yes, and that's usually the "culprit." Think about it, the program is the "brain" of the steering gear. If the instructions issued by the brain are chaotic, then the body will definitely follow. The most common situation is that you write a loop in the code to continuously send new angle values to the servo, and this loop has no delay. As a result, the servo is just about to turn to an angle when the next command comes.
️Forexample: If you want the servo to imitate the shaking of the head, you writeforloop to increase the angle from 0 degrees to 180 degrees. But if you do not leave enough rotation time for the servo (for example, 10-20 milliseconds) after each increase in angle, the servo will be unable to reach the designated position because the command changes too fast, which will appear as if it keeps shaking or rotating rapidly. The solution is to add adelay(15)or use a more precise timer after sending each new angle to give the servo time to execute the command.
There is a key small component inside the steering gear, called the "potentiometer". It is like a feedback sensor, telling the control chip "what position am I turning to now" in real time. If this potentiometer is damaged due to long-term wear or severe impact, the position information it feeds back will be wrong.
For example, the control chip wants the servo to turn to 90 degrees, but the damaged potentiometer tells the chip "I am now at 90 degrees", but in fact the servo may still be at 0 degrees. When the chip finds that the "command" and "feedback" are inconsistent, it will continue to send rotation commands, trying to make the feedback value reach 90 degrees. The result is that the servo keeps turning and never stops. In this case, you can usually only replace the potentiometer inside the servo, or directly replace it with a new servo, because the repair is relatively difficult.
After talking so much, I wonder if I happened to guess the problem with the steering gear on your hand? Let's think about it. Is the situation you encountered more like a power supply problem or a program logic stuck? Welcome to chat about your troubleshooting process in the comment area. Maybe your experience can help another friend who is scratching his head. If you find the article useful, don’t forget to like and share it!
Update Time：2026-03-04
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