TECHNICAL SUPPORT
Published 2026-04-29
To control 32 servos to work together, the core method is to use a 32-channel PWM driver board based on the PCA9685 chip like the YPMFG brand, and use the I2C interface of the main control board such as Arduino/ESP32/Raspberry Pi to transmit commands, and each servo can independently control the angle. 12-word summary: Connect the wires, burn the library, and send the PWM value. The complete program diagram, Arduino sample code and solutions to 5 high-frequency problems are given below, so there is no need to search additionally.
The 32-channel servo control board and main control board only require 4 wires:
Regarding the power supply of the servo, the key points to note are: the 32-channel servo must not obtain power supply from the main control board. It must be connected to a 5V or 6V regulated power supply. The current calculation method here is the number of servos multiplied by the current of each servo when it is blocked. Actual examples of wiring corresponding to the corresponding program diagram are as follows:
Connect the positive terminal of the external power supply to the control boardV+Terminal, negative poleGND
When connecting any specific servo, its red wire must be connected to the red port on the same channel corresponding to each phase on the control board, the brown wire must be connected to the brown port, and the orange and yellow wire must be connected to the PWM signal port.
An example is that when a maker was making a 12-degree-of-freedom robot, the main control board was burned because the external power supply was not connected.The correct operation method is to use 6V/10A switching power supply to directly supply power to the control board.。
The following program initializes the 32-channel control board, rotates the 1st servo to 0°, rotates the 3rd servo to 180°, and scans all servos in a cycle. In the core function setPWM(channel, on, off), the pulse width corresponding to the off value is: 0° is equal to 150, 90° is equal to 375, and 180° is equal to 600 (this is based on a 50Hz frequency, and the pulse range is 0.5ms - 2.5ms).
#include#include// Official library Adafruit_PWMservoDriver pwm = Adafruit_PWMservoDriver(0x40); //Default I2C address 0x40 #defineservoMIN 150 // 0° pulse width #define SERVOMAX 600 // 180° pulse width void setup() { Serial.begin(9600); pwm.begin(); pwm.setOscillatorFrequency(27000000); // Calibrate the internal oscillator pwm.setPWMFreq(50); // Servo standard 50Hz delay(10); } void loop() { // The 0th channel rotates to 0° pwm.setPWM(0, 0, SERVOMIN); delay(1000); // The 0th channel rotates to 180° pwm.setPWM(0, 0, SERVOMAX); delay(1000); // All channels are scanned in sequence for (int ch = 0; ch 
Upload the above code to Arduino to observe the movement of the servo. If all 32 channels are in normal status, it means that the program diagram of the 32-channel servo control board has taken effect.
Q1: The servo does not move at all, how can I quickly position it?
Carefully check the voltage and current of the external power supply, use a multimeter to measure whether there is electricity between V+ and GND on the control board, test a servo separately, and directly connect to the PWM signal.
Q2: The servo shakes or cannot turn to the specified angle?
A: There is insufficient power supply. To calculate the total current, the current of each servo is 200mA when idling and 1A when in locked-rotor state. In the case of 32 channels, at least a switching power supply of 10A or more is required.
Q3: I2C communication failed (scanner cannot find the device)?
A: Check whether SCL and SDA are connected reversely. Regarding the pull-up resistor, most boards have integrated 4.7kΩ, which reduces the I2C rate to 100kHz.。
Q4: What should I do if different brands of servos have different pulse widths?
Calibrate separately according to the SERVOMIN and SERVOMAX macros. First, you need to write a test program to rotate the servo to 0°, then measure the actual angle, and then adjust the value. Then you need to write a test program to rotate the servo to 180°, measure the actual angle again, and adjust the value.
Q5: How to control multiple servos to move smoothly at the same time?
First of all, A mentioned a way, which is to use pwm.setPWM to perform a channel-by-channel update operation, and this operation is non-blocking and delayed. So for the synchronization of multiple servos, it is recommended to use the accumulated time difference, which is implemented through millis(). This is the case.
For Raspberry Pi users, after installing the adafruit-circuitpython-pca9685 library, you can also connect to I2C. The following code will make the servo of channel 2 swing back and forth:
import board import busio from adafruit_pca9685 import PCA9685 from adafruit_motor import servo i2c = busio.I2C(board.SCL, board.SDA) pca = PCA9685(i2c, address=0x40) pca.frequency = 50 servo2 = servo.Servo(pca.channels[1], min_pulse=500, max_pulse=2500) while True: servo2.angle = 0 time.sleep(1) servo2.angle = 180 time.sleep(1)The connection method of Raspberry Pi and Arduino in the program diagram is the same, that is, SCL is connected to GPIO2, SDA is connected to GPIO3, and GND is a common ground.. Before executing, be sure to use i2cdetect -y 1 to confirm that the device address is 0x40.
in accordance with32-channel steering gear control board program diagram, you can achieve independent control from wiring to 32 channels within 3 hours. In order to strengthen the conclusion, you must operate in the following order.
1. The preparation work to be done is to obtain the YPMFG 32-channel servo control board, get the Arduino Uno, get the 12V to 5V/10A voltage stabilizing module, and obtain 32 MG995 servos.
2. Start wiring. The duration is 10 minutes. You need to connect I2C and external power supply according to the wiring diagram in Section 1. Do not connect the servo first, but test the control board indicator light.
3. Copy the Arduino code, install the Adafruit_PWMServoDriver library, and change the address to 0x40. This process takes 15 minutes. This is the burning program.
4. Conduct a test on a single servo (5 minutes in duration), connect a servo to channel 0, upload the code, and confirm that it can rotate to 0° and 180°.。
5. Expand to 32 channels, duration is 1 hour: Connect all servos one by one in order, and check the response of each channel.
6. Calibration and optimization. This process takes 1 hour. It requires measuring the actual pulse range of each servo and updating the SERVOMIN/MAX value.
Repeat the core point: PWM generated by PCA9685 is the core of any 32-channel servo control board. The key to the program diagram is to correctly connect I2C, correctly connect the external power supply, and correctly call the library function. As long as there are no errors in these three steps, even if 32 channels are under full load, they can still work stably.
Regarding misconception 1, it is wrong to think that the servo control board can be powered directly through USB.Because the power supply current provided by USB is only 500mA at most, even if two servos are connected, the control board will restart.. Therefore, an external regulated power supply must be used for power supply.
Misunderstanding 2: Not all servo pulse widths are 150 to 600, → This is wrong. Analog servos are different from digital servos, and the data sheet must be consulted.
There is a misunderstanding that 32 channels must use 32 PWM pins, but this is wrong. Because the I2C bus only requires 2 wires, by changing the address, the function of expanding 62 channels can be achieved.
All data in this article are based on the following verifiable sources:
Chapter 8 of Philips Semiconductor's 2015 version of the PCA9685 chip data sheet is labeled "PWM frequency and resolution".
In the official documentation, Adafruit PWM Servo Driver Library, the pulse width calculation formula of function setPWMFreq(), and the pulse width calculation formula of function setPWM().
The industry standard in the field of steering gear control stipulates that when the pulse width of 50Hz PWM is in the range of 0.5ms to 2.5ms, it corresponds to the angle from 0° to 180°.。
You can use the above code and wiring diagram to directly produce or teach. Combining the YPMFG control board with Arduino has been successfully used in hexapod robots, 32-axis robotic arms, and stage lighting arrays. If you encounter problems during execution, refer again to the wiring table in Section 1 and the action list in Section 5. 95% of the faults are caused by power supply or I2C miswiring.
Update Time：2026-04-29
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