摘要
使用树莓派操控PWM舵机.
平台信息
硬件信息:
- RaspberryPi zero 2w
- GPIO18:MOTOR_1
开发语言:
- Python
- Rust
依赖库:
- rppal = "0.14.1"
- anyhow = "1.0.74"
树莓派40pin的GPIO几种编号方式
[https://pinout.xyz/pinout/pin12_gpio18/]
[https://blog.csdn.net/lanchunhui/article/details/79055895]
树莓派GPIO基本分为如下的三种编码方式：物理引脚BOARD编码，BCM编码，以及 wiringPi 编码.
- BOARD编码
- BCM编码
- WiringPi编码
RPPAL库
[https://github.com/golemparts/rppal]
A Rust library that provides access to the Raspberry Pi's GPIO, I2C, PWM, SPI and UART peripherals.
实现
[https://github.com/golemparts/rppal/blob/master/examples/pwm_servo.rs]
[https://github.com/golemparts/rppal/blob/master/examples/gpio_servo_softpwm.rs]
代码
项目目录:
.
├── Cargo.lock
├── Cargo.toml
├── src
│ └── main.rs
└── target
├── aarch64-unknown-linux-musl
├── armv7-unknown-linux-gnueabihf
├── CACHEDIR.TAG
└── debug
Cargo.toml
[package]
name = "rpi_step_motor_rust"
version = "0.1.0"
edition = "2021"
# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
[dependencies]
anyhow = "1.0.74"
rppal = "0.14.1"
[target.aarch64-unknown-linux-musl]
linker = "arm-linux-musleabihf-gcc"
[target.armv7-unknown-linux-gnueabihf]
linker = "arm-linux-gnueabihf-gcc"
main.rs
/*
编译命令:
- cargo add rppal
- cargo add anyhow
- cargo run
*/
use std::error::Error;
use std::thread;
use std::time::Duration;
use rppal::gpio::Gpio;
// Gpio uses BCM pin numbering. BCM GPIO 18 is tied to physical pin 12.
const GPIO_PWM: u8 = 18;
// Servo configuration. Change these values based on your servo's verified safe
// minimum and maximum values.
// Period: 20 ms (50 Hz). Pulse width: min. 1200 µs, neutral 1500 µs, max. 1800 µs.
const PERIOD_MS: u64 = 20;
const PULSE_MIN_US: u64 = 1200;
const PULSE_NEUTRAL_US: u64 = 1500;
const PULSE_MAX_US: u64 = 1800;
fn main() -> Result<(), Box<dyn Error>> {
// Retrieve the GPIO pin and configure it as an output.
let mut pin = Gpio::new()?.get(GPIO_PWM)?.into_output();
// Enable software-based PWM with the specified period, and rotate the servo by
// setting the pulse width to its maximum value.
pin.set_pwm(
Duration::from_millis(PERIOD_MS),
Duration::from_micros(PULSE_MAX_US),
)?;
// Sleep for 500 ms while the servo moves into position.
thread::sleep(Duration::from_millis(500));
// Rotate the servo to the opposite side.
pin.set_pwm(
Duration::from_millis(PERIOD_MS),
Duration::from_micros(PULSE_MIN_US),
)?;
thread::sleep(Duration::from_millis(500));
// Rotate the servo to its neutral (center) position in small steps.
for pulse in (PULSE_MIN_US..=PULSE_NEUTRAL_US).step_by(10) {
pin.set_pwm(
Duration::from_millis(PERIOD_MS),
Duration::from_micros(pulse),
)?;
thread::sleep(Duration::from_millis(20));
}
println!("Rotate the servo done!\n");
Ok(())
// When the pin variable goes out of scope, software-based PWM is automatically disabled.
// You can manually disable PWM by calling the clear_pwm() method.
Python版本:
# -*- encoding:utf-8
from time import sleep
import RPi.GPIO as GPIO
GPIO.setmode(GPIO.BCM)#以BCM模式使用引脚
GPIO.setwarnings(False)# 去除GPIO警告
motor1_pin=18
def setServoAngle(servo, angle):#此函数将角度转换为占空比
pwm = GPIO.PWM(servo, 50)#设置pwm波为50Hz，也就是20ms一周期
pwm.start(8)#启动pwm
dutyCycle = angle / 18. + 3.#此公式由舵机调零推算得出（+3是偏移量）（占空比=%2.5+（目标角度/180°）*（%12.5-%2.5））
pwm.ChangeDutyCycle(dutyCycle)#调整pwm占空比
sleep(0.3)
pwm.stop()#关闭pwm
if __name__ == '__main__':
import sys
#servo = int(sys.argv[1])#外部输入参数
GPIO.setup(motor1_pin, GPIO.OUT)#设置指定的引脚为输出模式
while True:
setServoAngle(motor1_pin, 90)
sleep(1)
setServoAngle(motor1_pin, 0)
sleep(1)
GPIO.cleanup()#清除引脚占用
编译&运行
#配置环境
export https_proxy=http://192.168.31.94:7890 http_proxy=http://192.168.31.94:7890 all_proxy=socks5://192.168.31.94:7890
curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
source "$HOME/.cargo/env"
#编译
cargo add rppal
cargo add anyhow
cargo run
效果
