使用gpio readall查看针脚名称
$ gpio readall
+-----+-----+---------+------+---+---Pi 4B--+---+------+---------+-----+-----+
| BCM | wPi | Name | Mode | V | Physical | V | Mode | Name | wPi | BCM |
+-----+-----+---------+------+---+----++----+---+------+---------+-----+-----+
| | | 3.3v | | | 1 || 2 | | | 5v | | |
| 2 | 8 | SDA.1 | IN | 1 | 3 || 4 | | | 5v | | |
| 3 | 9 | SCL.1 | IN | 1 | 5 || 6 | | | 0v | | |
| 4 | 7 | GPIO. 7 | IN | 1 | 7 || 8 | 1 | IN | TxD | 15 | 14 |
| | | 0v | | | 9 || 10 | 1 | IN | RxD | 16 | 15 |
| 17 | 0 | GPIO. 0 | IN | 0 | 11 || 12 | 0 | IN | GPIO. 1 | 1 | 18 |
| 27 | 2 | GPIO. 2 | IN | 0 | 13 || 14 | | | 0v | | |
| 22 | 3 | GPIO. 3 | IN | 0 | 15 || 16 | 0 | IN | GPIO. 4 | 4 | 23 |
| | | 3.3v | | | 17 || 18 | 0 | IN | GPIO. 5 | 5 | 24 |
| 10 | 12 | MOSI | IN | 0 | 19 || 20 | | | 0v | | |
| 9 | 13 | MISO | IN | 0 | 21 || 22 | 0 | IN | GPIO. 6 | 6 | 25 |
| 11 | 14 | SCLK | IN | 0 | 23 || 24 | 1 | IN | CE0 | 10 | 8 |
| | | 0v | | | 25 || 26 | 1 | IN | CE1 | 11 | 7 |
| 0 | 30 | SDA.0 | IN | 1 | 27 || 28 | 1 | IN | SCL.0 | 31 | 1 |
| 5 | 21 | GPIO.21 | IN | 1 | 29 || 30 | | | 0v | | |
| 6 | 22 | GPIO.22 | IN | 1 | 31 || 32 | 0 | IN | GPIO.26 | 26 | 12 |
| 13 | 23 | GPIO.23 | IN | 0 | 33 || 34 | | | 0v | | |
| 19 | 24 | GPIO.24 | IN | 0 | 35 || 36 | 0 | IN | GPIO.27 | 27 | 16 |
| 26 | 25 | GPIO.25 | IN | 0 | 37 || 38 | 0 | IN | GPIO.28 | 28 | 20 |
| | | 0v | | | 39 || 40 | 0 | IN | GPIO.29 | 29 | 21 |
+-----+-----+---------+------+---+----++----+---+------+---------+-----+-----+
| BCM | wPi | Name | Mode | V | Physical | V | Mode | Name | wPi | BCM |
+-----+-----+---------+------+---+---Pi 4B--+---+------+---------+-----+-----+
如果出现：
Oops - unable to determine board type... model: 17
使用 Python 的 RPi.GPIO 模块进行 pwm 输出
# 设置接口定义模式
GPIO.setmode(GPIO.BCM)
# 设置GPIO口
GPIO.setup(FAN_GPIO, GPIO.OUT, initial=GPIO.HIGH)
# 初始化PWM的频率，frequency=50Hz
pwm = GPIO.PWM(FAN_GPIO, 50)
# 为防止风扇卡死，开机全速运行n秒
pwm.start(100)
# 修改pwm频率
pwm.ChangeFrequency(para_freq)
# 修改pwm占空比
pwm.ChangeDutyCycle(para_duty)
# 关闭pwm
pwm.stop()
# 清理GPIO资源
GPIO.cleanup()
读取 cpu 温度
vcgencmd measure_temp
cat /sys/class/thermal/thermal_zone0/temp
def get_cpu_temp():
with open('/sys/class/thermal/thermal_zone0/temp') as f:
cpu_temp = int(f.read())
return cpu_temp
开关三极管电路
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