TECHNICAL SUPPORT
Published 2026-02-26
Recently, I have seen many friends making some small inventions, small productions, or engaging in robot maker education. I found that everyone gets a little worried when they encounter gadgets that require precise control of angles, such as steering a car or making a robot wave. When searching forservos online, the most popular one is microservo9g sg90, but many people are still confused about how to choose and use it. In fact, this small steering gear is the key to many creative projects. Today we will talk about it and help you take this first step steadily.
You may see this little guy frequently on video websites or maker forums. It is indeed a star in the DIY circle. The reason is simple. It is small in size and weighs only 9 grams. It is very lightweight and is especially suitable for use in projects that require weight, such as mini robots, drone gimbals or model cars. Moreover, it is affordable, and if it breaks down or you want to upgrade, you don’t have to worry about replacing it with a new one. For novices who have just started to use servos, the cost of trial and error is very low, so they can play around with confidence.
More importantly, it has interfaces and control methods that have almost become industry standards. This means that you can easily connect it to mainstream control boards such as Raspberry Pi and micro:bit on the market. No complex driver circuit is required, and you can make it move with just a few lines of simple code. This plug-and-play feature allows you to focus more on realizing creative functions instead of worrying about how to connect the hardware, which greatly lowers the entry barrier.
If you search on Amazon, you will find that there are a wide variety of servos called SG90 with various prices. This makes it easy for people to be spoiled for choice, and you may accidentally buy an unreliable one. First of all, you have to look at one key point: whether it is genuine or a brand product with stable quality. The original SG90 has good quality control, tight gear engagement, small gap, and accurate rotation. You can read more pictures and comments in the product reviews. If someone says that the teeth are broken after just two days of use or the angle is completely wrong, then you have to be careful.
You can pay attention to the accessories of the steering gear. Reliable sellers usually come with a package of different styles of steering wheels (small parts fixed on the output shaft of the steering gear), which allows you to connect various connecting rods or brackets, and also comes with screws for installation. In addition, the length of the wire and whether the interface is standard are also worth noting. If these details are clearly displayed in the product details, it usually means that the seller is more professional and the product is relatively reliable, making it easier to buy and use.
After you get the servo, how do you make it start to move at your command? It's actually easier than you think. Usually SG90 has three wires: the brown wire is usually the ground wire, the red wire is connected to the power supply (usually 5V), and the orange wire is the signal wire, which is used to receive instructions from the control board. You only need to connect it to your or similar development board according to this rule, for example, connect the signal line to pin 9, and then upload a simple program, and it will automatically rotate to the specified angle.
The software part is equally uncomplicated. For example, by calling the official Servo library, you only need two or three lines of code to control the servo. For example, the command ".write(90);" tells the servo to turn to the 90-degree position. You can think of it as a precise rotary switch. By changing the angle value in the brackets, you can turn it to any position between 0 degrees and 180 degrees. It may only take ten minutes to go from "not knowing how to connect" to "the rudder is moving". The sense of accomplishment brought by this kind of instant feedback is where the fun of hands-on creation lies.
Many people excitedly connected the servo to the line, only to find that it either didn't move, shook constantly, or moved weakly. In all likelihood, there was a problem with the power supply. Although the SG9G is small, it is a motor after all, and it requires a lot of current at the moment of startup. If you directly use the 5V pin on the board to power it, especially if you bring several servos at the same time, the onboard voltage regulator chip will easily be overwhelmed, causing a voltage drop, and the servos will not work properly.
The most direct way to solve this problem is to use external power supply. You can prepare a separate 5V power supply, such as several dry batteries or a lithium battery, and connect the positive and negative poles of the power supply to the red and brown wires of the servo respectively. At the same time, connect the GND of the control board and the GND of the power supply together to ensure a common ground. In this way, the signal is provided by the control board and the power is provided by the external power supply. Each performs its own duties, and the steering gear can work stably and powerfully. Remember, only by giving the servo a "fed" environment can your project run stably.
Sometimes you will find that when the servo jumps directly from one angle to another, the movement seems very stiff, as if it was jerked. For example, if you want to be a robot and slowly turn its head, this stiff movement will not appear natural enough. How to make it turn around smoothly like a real person? A little trick here is to add some more steps in the middle instead of doing it in one step.
In the code, you can use a loop to increase the angle of the servo little by little. For example, when going from 0 degrees to 180 degrees, you can make it increase by 1 degree every 15 milliseconds instead of jumping directly from 0 to 180 degrees. In this way, the servo will turn at a relatively smooth speed. By adjusting the delay time, you can control how fast it rotates. The gentle rotation of many robot heads and the slow return of the model car's direction are all achieved using this simple "stepping" method. Once you learn this, your works will be much more refined in terms of movement details.
Once you have mastered the control of a single servo, you can start to think about combining it with your creative ideas to make more interesting things. The most common way to play is to use two servos to build a simple two-degree-of-freedom gimbal. One controls the left and right swing, and the other controls the up and down pitch. This way the camera or small sensor can scan around. It is very interesting to use it on a small surveillance or line-finding car. You can also use it on a robotic arm, using a servo for each joint to achieve the simple function of grabbing and carrying things by combining movements at different angles.
These projects may sound complicated, but there are actually a large number of open source tutorials on the Internet that you can refer to. Many enthusiastic makers will share their drawings and codes. You only need to download them, use 3D printing or laser cutting to make structural parts, then install the servo, upload the code, and your ideas will become reality step by step. From controlling one servo to coordinating multiple servos to work together, the process of exploration itself is full of fun and challenges. Are you ready to come up with your next interesting idea?
Okay, let’s talk about the micro servo 9g sg90 today. I wonder if you have any small projects on hand that you are conceiving and plan to use it to implement? Welcome to share your thoughts or ask your questions in the comment area. Let’s communicate and collide together. Maybe there will be more interesting inspirations. If you think this article is helpful to you, don’t forget to like it and share it with more friends who also like to create!
Update Time：2026-02-26
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