先看下ESP32开发板上哪些脚支持数模转换，途中紫色标记的ADC针脚都是支持的，在实际的使用中ADC1是最稳定的，GPIO36和GPIO39因为涉及到系统的启动问题，一般不会使用，用的比较多的是GPIO34和GPIO35。GPIO32、GPIO33、GPIO25、GPIO26也是可使用的，但是它涉及到触摸和一些其他功能，所以我们选择GPIO34和GPIO35。GPIO34和GPIO35作为普通GPIO只能输入不能输出。所以首选它作为模数转换的端口是比较合适的。
Wokwi网站上ESP32开发板是ESP32 Devkit V1版本的。
一、打开Wokwi网站，选择Micropython on ESP32开发板，添加一个滑动电位器
我们点击滑动电位器上方的问号，查看它的使用手册
wokwi-slide-potentiometer Reference | Wokwi DocsSliding variable resistor (linear potentiometer)/parts/wokwi-slide-potentiometer我们看到，滑动电位器的初始值是0，我们可以改变他的长度来调节它的大小。
关于ESP32的ADC介绍我们查看官方手册：
Quick reference for the ESP32 — MicroPython 1.19.1 documentation/en/latest/esp32/quickref.html#adc-analog-to-digital-conversion二、打印电位器ADC值
main.py
from machine import Pin,ADCfrom time import sleep_msport = ADC(Pin(34))while 1:print(port.read())sleep_ms(500)
diagram.json
{"version": 1,"author": "Anonymous maker","editor": "wokwi","parts": [{"type": "wokwi-esp32-devkit-v1","id": "esp","top": -44.67,"left": 19.33,"attrs": { "env": "micropython-0618-v1.19.1" }},{"type": "wokwi-slide-potentiometer","id": "pot1","top": 163.5,"left": -20.21,"attrs": { "travelLength": "60" }}],"connections": [[ "esp:TX0", "$serialMonitor:RX", "", [] ],[ "esp:RX0", "$serialMonitor:TX", "", [] ],[ "esp:D34", "pot1:SIG", "green", [ "h-99.9", "v10.14" ] ],[ "esp:3V3", "pot1:VCC", "green", [ "v-0.6", "h17.14", "v54.67", "h-173.33" ] ],[ "esp:GND.1", "pot1:GND", "black", [ "h0" ] ]]}
滑动电位器查看效果,我们看到输出从0到4095，默认是12位（2的12次方-1）。
也可以在线查看效果哦，点击下方链接
Wokwi Arduino and ESP32 Simulator/projects/341746287702442578
当然我们可以选择设置想要的位数，只需要加上这句话
from machine import Pin,ADCfrom time import sleep_msport = ADC(Pin(34))ADC.width(ADC.WIDTH_9BIT) # 设置输出位数while 1:print(port.read())sleep_ms(500)
三、脉宽调试
关于什么叫做脉宽调制（PWM）这里就不在说明，大家自行百度学习。
首先我们在Wokwi上选择Miropython with ESP32，打开开发网页。
同事查看ESP32 的官方文档关于PWM的描述：
Quick reference for the ESP32 — MicroPython 1.19.1 documentation/en/latest/esp32/quickref.html#adc-analog-to-digital-conversion接下来我们看代码：
main.py
# 脉宽调制例子# 通过滑动电位器产生不同的ADC值来调节LED灯的占空比# 使LED产生不同的亮度from machine import Pin,ADC,PWMfrom time import sleep_msled = PWM(Pin(25)) # 定义PWM在端口25adc = ADC(Pin(34)) # 定义ADC在端口34# LED灯的亮度不能超过1023，否则跑出异常duty must be from 0 to 1023adc.width(ADC.WIDTH_10BIT) # 设置ADC的位数为9(0-1023)while True:value = adc.read() # 读取端口34的ADC值led.duty(value) # 设置PWM波的占空比print(value) # 打印PWM波的占空比sleep_ms(300)
diagram.json
{"version": 1,"author": "Anonymous maker","editor": "wokwi","parts": [{"type": "wokwi-esp32-devkit-v1","id": "esp","top": 0,"left": 0,"attrs": { "env": "micropython-0618-v1.19.1" }},{"type": "wokwi-slide-potentiometer","id": "pot1","top": 187.5,"left": -46.63,"attrs": { "travelLength": "30" }},{"type": "wokwi-led","id": "led1","top": 48.89,"left": -134.23,"attrs": { "color": "red" }},{"type": "wokwi-resistor","id": "r1","top": 81.93,"left": -76.59,"attrs": { "value": "470" }}],"connections": [[ "esp:TX0", "$serialMonitor:RX", "", [] ],[ "esp:RX0", "$serialMonitor:TX", "", [] ],[ "esp:D25", "r1:2", "green", [ "h0" ] ],[ "r1:1", "led1:A", "green", [ "v0" ] ],[ "led1:C", "esp:GND.2", "green", [ "v0" ] ],[ "pot1:VCC", "esp:3V3", "red", [ "h-8.16", "v-26.33", "h172.71", "v-42.74" ] ],[ "pot1:GND", "esp:GND.1", "black", [ "v0" ] ],[ "pot1:SIG", "esp:D34", "green", [ "h-98.01", "v-209.46" ] ]]}
查看效果
或者通过网页查看效果
Wokwi Arduino and ESP32 Simulator/projects/341747547238302292
我们在加个蜂鸣器看个小效果哈：
蜂鸣器buzzer的使用文档见：
wokwi-buzzer Reference | Wokwi DocsA piezoelectric buzzer/parts/wokwi-buzzer
main.py
# 脉宽调制例子# 通过滑动电位器产生不同的ADC值来调节LED灯的占空比# 使LED产生不同的亮度from machine import Pin,ADC,PWMfrom time import sleep_msbuzzer = PWM(Pin(14)) #定义蜂鸣器的PWM在端口14buzzer.duty(512) # 设置蜂鸣器的占空比led = PWM(Pin(25)) # 定义PWM在端口25adc = ADC(Pin(34)) # 定义ADC在端口34# LED灯的亮度不能超过1023，否则跑出异常duty must be from 0 to 1023adc.width(ADC.WIDTH_10BIT) # 设置ADC的位数为9(0-1023)while True:value = adc.read() # 读取端口34的ADC值led.duty(value) # 设置PWM波的占空比# 此处加1是因为最小频率是1HZ,否则抛出异常freqency must be from 1Hz to 40MHzbuzzer.freq(value + 1 ) print(value) # 打印PWM波的占空比sleep_ms(300)
diagram.json
{"version": 1,"author": "Anonymous maker","editor": "wokwi","parts": [{"type": "wokwi-esp32-devkit-v1","id": "esp","top": 0,"left": 0,"attrs": { "env": "micropython-0618-v1.19.1" }},{"type": "wokwi-slide-potentiometer","id": "pot1","top": 190.76,"left": -57.51,"attrs": { "travelLength": "30" }},{"type": "wokwi-led","id": "led1","top": 48.89,"left": -134.23,"attrs": { "color": "red" }},{"type": "wokwi-resistor","id": "r1","top": 81.93,"left": -76.59,"attrs": { "value": "470" }},{"type": "wokwi-buzzer","id": "bz1","top": 28.37,"left": -228.1,"attrs": { "volume": "0.1" }}],"connections": [[ "esp:TX0", "$serialMonitor:RX", "", [] ],[ "esp:RX0", "$serialMonitor:TX", "", [] ],
查看效果：
也可用网页查看哦~~~
Wokwi Arduino and ESP32 Simulator/projects/341754674259427923
