How To Control Multiple Servos With Arduino To Easily Solve The Problem Of Signal Instability And Jitter

Have fun: Easily control multipleservos and let your creativity come into play!

Many friends will encounter the same "happy trouble" when they first start using interactive devices or robots: they need to control severalservos in a project, but the interfaces on the board seem to be insufficient, or after connecting them, they find that they move stuck and do not obey instructions. Don’t worry, this is actually a hurdle that every maker goes through. Today we will talk about how to control multipleservos at the same time using Steady to make your little invention truly "alive".

Why does one board control multiple servos causing "fighting"?

This starts with the working principle of the steering gear. It has a motor inside and an adjustable resistor to detect the position. In order to accurately turn to the angle you specify, it needs to "see" the current position at all times, which actually requires a continuous pulse signal to maintain. It's more than enough to handle when you're only controlling one or two servos. But once the number increases, for example, if you want to install six joints on the robot, trouble begins. The single-threaded brain needs to continuously generate precise pulses for each servo. When there are too many tasks, it is easy to be "rushed", resulting in unstable signals and the servo will naturally shake.

Is it okay to use a steering gear library?

The built-in Servo library is indeed very convenient. You can activate a servo with just a few lines of code. For controlling two or three servos at the same time, it is fully capable in most non-professional projects. Its principle is to use the timer of the microcontroller to quietly generate pulses in the background. But here's the problem, a timer usually can only perfectly take care of 12 servos (the specific number varies from chip to chip). If the servos in your project exceed this number, or you need to use this timer to do other things (such as generating PWM wave-modulated lights), then the system will conflict. Therefore, it is okay to use it for small projects, but when there are more servos, we have to change our thinking.

What should I do if I want to control many servos at the same time?

When you find that the Servo library is not enough, or the number of servos exceeds 8 or 10, the most reliable solution is to introduce a servo control board, also called a driver board. You can think of it as a smart "setter". You only need to tell this board through two wires (I2C communication protocol): "You turn the No. 1 servo to 90 degrees and the No. 2 servo to 120 degrees." All the rest of the heavy work of generating precise pulses is completed independently by this board. In this way, you are completely liberated to process sensor data and perform logical operations, and you can easily control up to 16 servos with one board. Through cascading, the number is almost unlimited.

How to wire and set up the driver board

This little board is super easy to use. First, connect the power supply: the board generally has two larger terminals, V+ and GND, which are used to power the servo. Remember to connect an external power supply with sufficient power (such as a 5V 10A switching power supply). Do not try to take power from the 5V port, otherwise it will burn out in an instant. Then, connect the signals: SCL on the board is connected to A5 (UNO board), SDA is connected to A4, VCC (logic power supply) is connected to 5V, and GND is connected together. Finally, install the "PWM Servo" library in it, run a few lines of sample code, and your 16 servos will be able to obey each other. The whole connection is as clear as building blocks.

How to provide stable power supply to so many servos safely?

This is the most critical link in the entire project, directly related to success or failure and safety. The current of the steering gear is very large when it is started and locked. If several servos operate at the same time, the instantaneous current may be as high as more than ten amps. Remember one principle:signals and motivation should be separated. It is enough to use USB power or 9V battery power, which is responsible for the brain. The steering gear group must be powered by an independent, high-power power supply. A reliable way is to buy a 5V regulated switching power supply. The power is calculated according to the number of servos (for example, one servo is calculated as 1A, and 10 servos require 10A). Connect the positive and negative poles of the power supply to the power supply end of the board. At the same time, in order to ensure a common ground (the signal reference is consistent), connect the negative pole of the power supply to the GND. In this way, your power system is considered stable.

What are the techniques in software programming to make movements smoother?

The hardware is set up, and there are some tips on the software. For example, if you still use the Servo library to control a small number of servos, try not to let all the servos start turning at the same time. You can add a small delay in the code to let them start in sequence. This can effectively avoid restarting due to excessive starting current. If used, you can take advantage of its benefits to achieve a softer motion trajectory. For example, don't directly jump the servo from 0 degrees to 180 degrees. Instead, increase the angle little by little in the loop, and with a little delay, you can create a smooth effect like a robot slowly raising its hand and slowly turning its head, making the work look more spiritual.

I hope these sharings can help you solve the problem of controlling multiple servos. I wonder what is the most difficult servo application scenario you encounter when working on a project? Do you want to give the robot a complex walking gait, or do you want a bunch of small things to dance at the same time? Welcome to share your ideas and problems in the comment area, let’s discuss it together! If you find the content useful, don't forget to like and share it with more friends who need it.