seeed-studio/seeed_pca9685

Library for the Grove - 16-Channel Servo Driver(PCA9685)

Seeed PCA9685 Library

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This is the Arduino Library for Seeed's PCA9685 based products. For now, it's Grove - 16-Channel Servo Driver(PCA9685).

Usage Tips

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The PCA9685 is an I2C-bus controlled 16-channel LED controller. It can be used as RGB or RGBA LED Drivers, Servo Drivers, etc.

Please note that PCA9685 has a ALL CALL I2C-bus address 0x70, this address is for programming all the PCA9685s in the bus at the same time. This address is enabled by default and disabled after PCA9685::init() or ServoDriver::init().

Examples

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Servo

This example drives 8 servos in turns. The library provides a sub-class of class PCA9685, named ServoDriver. In that class, ServoDriver::setAngle() can be used to control a servo directly.

Led

PCA9685 can also drive leds with PWM.

Change I2C address

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The default I2C address of Grove - 16-Channel Servo Driver(PCA9685) is 0x7f. If you need to change the I2C address, there are 6 hardware address pin on the back and they are default to HIGH. Cut the line between the right two pads and solder the left two pads together to set it to LOW.

The following picture is the address table of PCA9685:

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This software is written by Jerry Yip for seeed studio and is licensed under The MIT License. Check License.txt for more information.

Contributing to this software is warmly welcomed. You can do this basically by
forking, committing modifications and then pulling requests (follow the links above
for operating guide). Adding change log and your contact into file header is encouraged.
Thanks for your contribution.

Seeed Studio is an open hardware facilitation company based in Shenzhen, China.
Benefiting from local manufacture power and convenient global logistic system,
we integrate resources to serve new era of innovation. Seeed also works with
global distributors and partners to push open hardware movement.

seeed_pca9685's Issues

Where does the magic number 2.46 come from?

How do you get the formula min = (2.46 * min_pulse_width) / 10.0 - 1?

void ServoDriver::setServoPulseRange(uint16_t min_pulse_width, uint16_t max_pulse_width, uint16_t max_servo_degree) {
    float min, max;
    min = (2.46 * min_pulse_width) / 10.0 - 1;
    max = (2.46 * max_pulse_width) / 10.0 - 1;
    _min_pulse_width = min;
    _max_pulse_width = max;
    _max_servo_degree = max_servo_degree;
}

feature request: ServoDriver class: servo.setAngle(i, angle, rotationspeed)

feature request: ServoDriver class: servo.setAngle(byte i, int angle, float rotationspeed)
i: servo channel
angle: degrees (endpoint)
rotationspeed: degrees per second

e.g.,

servo.setAngle(i, 90); // let the servo move to position 90° immediately
delay(1000);
servo.setAngle(i, 180, 10.0); // moves the servo from the current position (90°) to position 180° by a rotation speed of 10°/sec

The function must not be blocking, so that a following command can be started immediately before the further movement has been finished (simultaneous movement)

servo.setAngle(1, 180, 10.0);
servo.setAngle(2, 45, 5.0);