TECHNICAL SUPPORT
Published 2026-02-20
Presumably many friends who are new toservos will encounter this problem: holding theservos and development board in their hands, looking at a few wires, and not knowing how to connect them. Don’t worry, this problem is actually very simple. Once you understand the logic behind it, you can solve it as easily as inserting building blocks. Today we will explain this matter thoroughly, so that you can get started immediately when you see theservo.
When you get a servo, the most troublesome thing is the three wires sticking out of it. Generally speaking, these three wires have standard color distinctions: the brown (or black) wire is the negative pole, which is the ground wire; the red wire is the positive pole of the power supply; and the orange (or yellow, white) wire is the signal wire. This is like a well-established rule that almost all servos follow. As long as you remember the formula "brown, negative, red, positive and orange signals", you can identify the responsibilities of each wire at a glance and lay a solid foundation for the next connection. If you are not sure, you can test it again with a multimeter to make sure everything is safe.
Although there are many interfaces on the development board, not just any one can directly control the servo. The signal line of the servo needs to be connected to the pin on the development board that can output a PWM (pulse width modulation) signal. You can understand PWM as a special "switch" language that tells the servo to which angle to turn by quickly changing the duration of the high level. Most development boards, such as Uno, will mark "~" symbols next to certain digital pins. These are PWM pins. Finding them means finding the correct channel to "talk" to the steering gear.
This issue is very critical, and many people fail to debug it for the first time. The steering gear requires relatively large current when rotating, especially when starting with load. If you only use the 5V output port of the development board to power the servo, it is likely that the development board will restart due to insufficient current, or the servo will be weak, shake, or not rotate. ️ A reliable method is to connect the power cord and ground wire of the servo directly to an external power source, such as a battery pack or a specialized voltage stabilizing module. At the same time, connect the ground wire of the development board and the external power supply together so that they share the same voltage reference point so that the signal can be transmitted stably.
Now let's do it in practice, assuming you are using Uno and a most common SG90 9g servo. ️ The first step is to see clearly the color of the servo cable: brown, red, orange. ️ In the second step, connect the brown ground wire to the GND (ground) pin of the development board. ️ Step 3: Connect the red power wire to the positive terminal of the external 5V power supply, and connect the negative terminal of the external power supply to the GND of the development board. ️ Step 4, connect the orange signal wire to a PWM pin of the development board, such as pin 9. In this way, the hardware connections are all completed. Is it easier than you think? The whole process is to find the correct wires, find the right pins, and get the power supply.
Once the hardware is connected, it is only half the battle; code is still needed to direct it. Open your IDE and enter a simple servo test program. First, you need to include the# library at the beginning of the code, and then create a servo object, such asServo ;;. Insetup()function, use.(9);to bind the servo object to the pin 9 you connected. Finally, inloop()function, use instructions like.write(0);and.write(90);to make the servo swing between different angles. If after uploading the code, the servo rotates obediently, congratulations, the connection is completely correct!
Sometimes you will find that although it is clearly written as 90 degrees, the position of the servo seems to be a little off. This is usually caused by two reasons. First, the potentiometer of the steering gear itself has a slight error, which is determined by the mechanical characteristics. The second is some cheap servos, the angle range corresponding to their PWM signal is slightly different from the standard library. The calibration method is also very straightforward, you can achieve it by fine-tuning the pulse width in the code. For example, instead of using thewrite()function directly, you can use the()function to try different pulse width values (for example, from 544 to 2400 microseconds) to find the accurate pulse width corresponding to 0 degrees and 180 degrees, so that the servo can be directed where to hit.
After seeing this, I believe you have fully grasped the essence of the connection between the servo and the development board. I don’t know if you are going to use the servo to make an interesting robot car or to control a robotic arm in actual operation? Welcome to share your creative projects in the comment area and exchange experiences together! If you think this article is helpful to you, don’t forget to like it and share it with more friends.
Update Time：2026-02-20
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