TECHNICAL SUPPORT
Published 2026-03-08
Have you ever encountered such a situation - you happily installed theservoon your robot or car, only to find that it either kept shaking, or could not turn in place, or even stopped at all? In fact, many times, the problem does not lie in your code, but that the littleservois not selected correctly. There are so many "emax microservo" on the market. They all look similar, but they are very different in use. Today we are going to talk about how to choose and how to use this little thing to make your work a success.
Choosing a servo is like choosing a heart for a robot. If it's too weak, it can't run; if it's too strong, it can't fit. You first need to figure out how much effort your project requires. For example, making a manipulator to grab a small object requires completely different torque than adjusting the camera angle of a drone. In emax's micro servo series, classic models like the ES08A have a torque of about 1.8kg, which is enough for most lightweight models and robot arms.
Next is the size and weight. Micro means tiny, but there are still subtle differences between different models. You have to get a ruler and measure the space you have set aside. Don't underestimate the gap of a few millimeters. If it can't fit in, you will have to redesign the bracket, which will be too much trouble. There is also the shape of the fixed ears, whether it is unilateral or bilateral, whether it is a round hole or a long hole, these details will affect the convenience of your installation.
The shaking is most likely caused by insufficient power supply. When the servo is started and locked, the instantaneous current will surge very high. If the output of your battery or voltage stabilizing module cannot keep up, once the voltage drops, the internal circuit of the servo will be confused, which will be manifested by the constant shaking of the servo. You can try to use a better power supply, or connect a large capacitor in parallel to the servo power line, which can often solve the problem.
Of course, it is also possible that the signal is interfered with. Especially when the servo cable is relatively long and tied together with the motor cable, the electromagnetic interference generated by the motor will be transmitted to the servo signal cable. Try running the signal wire separately, or use a shielded wire. If it still shakes, you need to check whether the installation of the servo plate is smooth and whether there is any lag. Too much resistance will cause the servo to be positioned inaccurately, and adjustment back and forth will cause jitter.
If you want the servo to turn accurately, the first step is to calibrate the neutral point. There is a slight difference in accuracy between emax's analog servos and digital servos. Digital servos process signals at a higher frequency and can theoretically stop at a designated position more accurately. But when you actually use it, you will find that the response of the digital servo is faster and more responsive.
The adjustment accuracy mainly depends on the PWM signal sent by your control board. You have to make sure that the signal's pulse width range matches the servo's travel. For example, the standard servo generally has a range of 0.5ms to 2.5ms corresponding to 0 to 180 degrees, but some emax models may not have the standard 180 degree stroke. You can find the data sheet of the specific model from the official website, find the precise pulse width range, and then set it in your code, so that the servo can exert its best accuracy and hit wherever it is pointed.
This depends on your project budget and performance requirements. Analog servos are cheap and simple in structure, and are completely sufficient for less complex applications such as remote control car steering and simple robot joints. Its working principle is to continuously receive signals and then adjust quickly, which is simple and crude.
But if you have requirements for response speed, such as making a small bionic robot, or need the servo to make small adjustments frequently and quickly, then digital servo is a better choice. There is a small chip inside it that can process signals at a higher frequency, start faster, and brake more stably. The price is that it is a little more expensive, and it consumes a little more power than an analog servo when in standby. So, just look at the food, choose analog for beginners, and pursue performance and numbers.
Although the servo is small, it is also a precision component. If you want it to survive for a long time, you must pay attention to a few points. The first thing is not to let it stall for a long time, that is, to send a signal to it to turn to a certain position, but it is stuck by the mechanical structure and cannot turn. At this time, the motor is still working hard and the current is huge. The internal gears and motor will overheat and burn out soon. Therefore, when designing the structure, be sure to ensure that the steering gear is smooth within its travel range.
The second is regular cleaning. When dirt, sand and other dirt get in, it will accelerate the wear of the gears, make the false position larger and larger, and eventually the accuracy will be lost. If your work often runs outdoors, consider adding a dust cover to the servo. There are also screws connecting the servo plate. Tighten them but not too hard to prevent them from slipping. After each game, check the wires to see if they are worn or damaged. These little habits can help you save a lot of money on new servos.
The most common pitfall is that the screws are tightened incorrectly. The screws that fix the servo should not be too long. If they are too long, they will penetrate the motor or gear inside and cause them to be scrapped. Be sure to use the screws included in the package, or measure the depth accurately. Another pitfall is that the servo plate is installed backwards. Before powering on to determine the neutral position, I installed the servo plate based on feeling. After powering on, I found that it was not in the center at all. To adjust it, I had to remove it, which was time-consuming and labor-intensive.
The correct approach is to first connect the servo to the receiver or controller, turn it on to the neutral position (usually 90 degrees), and then install the servo plate. At this time, connect the rocker arm or bracket you made to ensure that the range of movement is symmetrical. Also, be sure to confirm the positive and negative poles before wiring, red is positive and black is negative, and the signal wire is usually white or yellow. If the connection is reversed, the servo will immediately smoke, and the tuition is not cheap.
Having said all that, I wonder what interesting things you plan to use the servo for in your project at hand? Is it a robotic arm, a six-legged robot, or some other new trick? Welcome to chat about your thoughts in the comment area, and don’t forget to share this article with friends who play models together, so that everyone can avoid detours!
Update Time：2026-03-08
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