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前言

材料：树莓派 摄像头 SG90舵机两个 PCA9685拓展板 led小灯 蜂鸣器模块

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一、树莓派引脚介绍

树莓派引脚对照表

可以看到一共有三种定义方式 分别是Wiring Pi编码，BCM编码和BOARD物理引脚编码。

1.1引脚设置

在最开始终端输入

sudo raspi-config 

进入设置 后找到

Interfacing Options 

进入 找到

Remote GPIO 

开启GPIO

二、代码书写

2.1引入库

在最开始导入库

import RPi.GPIO as GPIO #1导入引脚库 GPIO.setmode(GPIO.BOARD) # 2定义引脚方式 此处为BOARD编码 GPIO.setup(channel, GPIO.OUT) # 3建立通道 该函数需要两个参数 第一个为引脚编号 第二个为模式定义 #此处为输出 GPIO.output(7, True)#4 驱动通道 GPIO.cleanup()#5清除 释放资源 

2.2示例代码点亮led 响蜂鸣器

#导入gpio模块 调用引脚 import RPi.GPIO as GPIO #初始化引脚模式为BOARD 屏蔽警告 GPIO.setmode(GPIO.BOARD) GPIO.setwarnings(False) #引脚定义 蜂鸣器接的35引脚 led接的37引脚 beep=35 led=37 GPIO.setup(beep,GPIO.OUT)#设置gpio模式为输出 GPIO.setup(led,GPIO.OUT) GPIO.output(led,GPIO.HIGH)#开灯 GPIO.output(led,GPIO.LOW)#关灯 GPIO.output(beep,GPIO.HIGH)#蜂鸣器响 GPIO.output(beep,GPIO.LOW)#蜂鸣器关 

三完整代码 图片

#!/usr/bin/env python2 # -*- coding: utf-8 -*- """ * @par Copyright (C): 2010-2020, hunan CLB Tech * @file 50_Hand_gestures.py * @version V2.0 * @details * @par History @author: zhulin """ import cv2 import numpy as np import math import time import sys import Adafruit_PCA9685#导入PCA9685模块 #设置编码为utf-8 import importlib importlib.reload(sys) #sys.setdefaultencoding('utf8') #导入gpio模块 调用引脚 import RPi.GPIO as GPIO #初始化引脚模式为BOARD 屏蔽警告 GPIO.setmode(GPIO.BOARD) GPIO.setwarnings(False) #引脚定义 蜂鸣器接的35引脚 led接的37引脚 beep=35 led=37 GPIO.setup(beep,GPIO.OUT)#设置gpio模式为输出 GPIO.setup(led,GPIO.OUT) #初始化PCA9685和舵机 servo_pwm = Adafruit_PCA9685.PCA9685() # 实例话舵机云台 # 设置舵机初始值，可以根据自己的要求调试 servo_pwm.set_pwm_freq(60) # 设置频率为60HZ servo_pwm.set_pwm(5,0,325) # 底座舵机 servo_pwm.set_pwm(4,0,325) # 倾斜舵机 time.sleep(1) #初始化摄像头并设置阙值 cap = cv2.VideoCapture(0) cap.set(3,120) cap.set(4,160) while(1): try: #an error comes if it does not find anything in window as it cannot find contour of max area #therefore this try error statement ret, frame = cap.read() frame=cv2.flip(frame,1) kernel = np.ones((3,3),np.uint8) #define region of interest roi=frame[0:300, 0:300] cv2.rectangle(frame,(0,0),(300,300),(0,255,0),0) hsv = cv2.cvtColor(roi, cv2.COLOR_BGR2HSV) # define range of skin color in HSV lower_skin = np.array([0,20,70], dtype=np.uint8) upper_skin = np.array([20,255,255], dtype=np.uint8) #extract skin colur imagw mask = cv2.inRange(hsv, lower_skin, upper_skin) #extrapolate the hand to fill dark spots within mask = cv2.dilate(mask,kernel,iterations = 4) #blur the image mask = cv2.GaussianBlur(mask,(5,5),100) #find contours _,contours,hierarchy= cv2.findContours(mask,cv2.RETR_TREE,cv2.CHAIN_APPROX_SIMPLE) #find contour of max area(hand) cnt = max(contours, key = lambda x: cv2.contourArea(x)) #approx the contour a little epsilon = 0.0005*cv2.arcLength(cnt,True) approx= cv2.approxPolyDP(cnt,epsilon,True) #make convex hull around hand hull = cv2.convexHull(cnt) #define area of hull and area of hand areahull = cv2.contourArea(hull) areacnt = cv2.contourArea(cnt) #find the percentage of area not covered by hand in convex hull arearatio=((areahull-areacnt)/areacnt)*100 #find the defects in convex hull with respect to hand hull = cv2.convexHull(approx, returnPoints=False) defects = cv2.convexityDefects(approx, hull) # l = no. of defects l=0 #code for finding no. of defects due to fingers for i in range(defects.shape[0]): s,e,f,d = defects[i,0] start = tuple(approx[s][0]) end = tuple(approx[e][0]) far = tuple(approx[f][0]) pt= (100,180) # find length of all sides of triangle a = math.sqrt((end[0] - start[0])**2 + (end[1] - start[1])**2) b = math.sqrt((far[0] - start[0])**2 + (far[1] - start[1])**2) c = math.sqrt((end[0] - far[0])**2 + (end[1] - far[1])**2) s = (a+b+c)/2 ar = math.sqrt(s*(s-a)*(s-b)*(s-c)) #distance between point and convex hull d=(2*ar)/a # apply cosine rule here angle = math.acos((b**2 + c**2 - a**2)/(2*b*c)) * 57 # ignore angles > 90 and ignore points very close to convex hull(they generally come due to noise) if angle <= 90 and d>30: l += 1 cv2.circle(roi, far, 3, [255,0,0], -1) #draw lines around hand cv2.line(roi,start, end, [0,255,0], 2) l+=1 #print corresponding gestures which are in their ranges font = cv2.FONT_HERSHEY_SIMPLEX if l==1: if areacnt<2000: cv2.putText(frame,'Put hand in the box',(0,50), font, 2, (0,0,255), 3, cv2.LINE_AA) else: if arearatio<12: cv2.putText(frame,'0',(0,50), font, 2, (0,0,255), 3, cv2.LINE_AA) elif arearatio<17.5: cv2.putText(frame,'Best of luck',(0,50), font, 2, (0,0,255), 3, cv2.LINE_AA) else: cv2.putText(frame,'1',(0,50), font, 2, (0,0,255), 3, cv2.LINE_AA) GPIO.output(led,GPIO.HIGH)#开灯 elif l==2: cv2.putText(frame,'2',(0,50), font, 2, (0,0,255), 3, cv2.LINE_AA) GPIO.output(led,GPIO.LOW)#关灯 elif l==3: if arearatio<27: cv2.putText(frame,'3',(0,50), font, 2, (0,0,255), 3, cv2.LINE_AA) GPIO.output(beep,GPIO.HIGH)#蜂鸣器响 else: pass#屏蔽ok手势 #cv2.putText(frame,'ok',(0,50), font, 2, (0,0,255), 3, cv2.LINE_AA) elif l==4: cv2.putText(frame,'4',(0,50), font, 2, (0,0,255), 3, cv2.LINE_AA) GPIO.output(beep,GPIO.LOW)#蜂鸣器关 elif l==5: cv2.putText(frame,'5',(0,50), font, 2, (0,0,255), 3, cv2.LINE_AA) GPIO.output(led,GPIO.HIGH)#开灯 time.sleep(0.5) GPIO.output(beep,GPIO.HIGH)#蜂鸣器响 time.sleep(0.5) GPIO.output(beep,GPIO.LOW)#蜂鸣器关 time.sleep(0.5) GPIO.output(led,GPIO.LOW)#关灯 time.sleep(0.5) elif l==6: cv2.putText(frame,'reposition',(0,50), font, 2, (0,0,255), 3, cv2.LINE_AA) else : cv2.putText(frame,'reposition',(10,50), font, 2, (0,0,255), 3, cv2.LINE_AA) #show the windows cv2.imshow('mask',mask) cv2.imshow('frame',frame) except: pass k = cv2.waitKey(5) & 0xFF if k == 27: break cv2.destroyAllWindows() cap.release() 

实现功能 ：
识别手势1 伸一个指头 点亮LED 灯
识别手势2 伸两个指头 关闭LED 灯
识别手势3 伸三个指头 响蜂鸣器
识别手势4 伸四个指头 蜂鸣器关
识别手势5 伸5个指头 声光警报

成品展示：