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Micropython and ESP32 blink an led

by shedboy71

In this example we will use Micropython on an ESP32, the tool I will use is called uPyCraft which makes the task easy

You will need to download the tool first, the latest version I have seen is available from – https://git.oschina.net/dfrobot/upycraft/raw/master/uPyCraft_V0.27.exe.

Start the tool and connect your ESP32 board

Open up the Tools and set the Serial port for your ESP32 board
Open up the Tools and set the ESP32 board in the board menu

Parts List

1 x ESP32 board
1 x LED
1 x 470 ohm resistor
1 x breadboard
Connecting wire

 

Schematic

esp32 and led layout

esp32 and led layout

 

Code

Insert the code below into the editor and click on the DownloadRun button

import time
from machine import Pin
led=Pin(15,Pin.OUT)

while True:
led.value(1)
time.sleep(0.5)
led.value(0)
time.sleep(0.5)

Links

Official DOIT ESP32 Development Board WiFi+Bluetooth Ultra-Low Power Consumption Dual Core

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Tutorials

A basic ESP32 Web server example

by shedboy71

In this example we will create a basic web server with an ESP32, we will then serve a we page with an on and off button which will switch an LED on and off

Parts Required

1x ESP32 Dev Module (Lolin32)
1x LED
1x Breadboard
1x 470 Ohm Resistor
Jumper wires

Layout

This was the best ESP32 fritzing part I could find

esp32 and led layout

esp32 and led layout

Code

Adding support for ESP32 boards – showed how to add support to the Arduino IDE

#include <WiFi.h>

// Replace with your network credentials
const char* ssid     = "iainhendry";
const char* password = "iain061271";

WiFiServer server(80);

const int led =  15;      // the number of the LED pin

// Client variables 
char linebuf[80];
int charcount=0;

void setup() 
{
  // initialize the LED as an output:
  pinMode(led, OUTPUT);
  //Initialize serial and wait for port to open:
  Serial.begin(115200);
  while(!Serial) {
  }
  
  // We start by connecting to a WiFi network
  Serial.println();
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);
  
  WiFi.begin(ssid, password);
  
  // attempt to connect to Wifi network:
  while(WiFi.status() != WL_CONNECTED) 
  {
    // Connect to WPA/WPA2 network.
    delay(500);
    Serial.print(".");
  }
  Serial.println("");
  Serial.println("WiFi connected");
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP()); 
  server.begin();
}

void loop() 
{
  // listen for incoming clients
  WiFiClient client = server.available();
  if (client) 
  {
    Serial.println("New client");
    memset(linebuf,0,sizeof(linebuf));
    charcount=0;
    // an http request ends with a blank line
    boolean currentLineIsBlank = true;
    while (client.connected()) 
    {
      if (client.available()) 
      {
        char c = client.read();
        Serial.write(c);
        //read char by char HTTP request
        linebuf[charcount]=c;
        if (charcount<sizeof(linebuf)-1) charcount++;

        if (c == '\n' && currentLineIsBlank) 
        {
          // send a standard http response header
          client.println("HTTP/1.1 200 OK");
          client.println("Content-Type: text/html");
          client.println("Connection: close");  // the connection will be closed after completion of the response
          client.println();
          client.println("<!DOCTYPE HTML><html><head>");
          client.println("<meta name=\"viewport\" content=\"width=device-width, initial-scale=1\"></head>");
          client.println("<h1>ESP32 - Web Server example</h1>");
          client.println("<p>LED <a href=\"on\"><button>ON</button></a> <a href=\"off\"><button>OFF</button></a></p>");
          client.println("</html>");
          break;
        }
        if (c == '\n') 
        {
          // you're starting a new line
          currentLineIsBlank = true;
          if (strstr(linebuf,"GET /on") > 0)
          {
            Serial.println("LED ON");
            digitalWrite(led, HIGH);
          }
          else if (strstr(linebuf,"GET /off") > 0)
          {
            Serial.println("LED OFF");
            digitalWrite(led, LOW);
          }

          // you're starting a new line
          currentLineIsBlank = true;
          memset(linebuf,0,sizeof(linebuf));
          charcount=0;
        } 
        else if (c != '\r') 
        {
          // you've gotten a character on the current line
          currentLineIsBlank = false;
        }
      }
    }
    // give the web browser time to receive the data
    delay(1);

    // close the connection:
    client.stop();
    Serial.println("client disconnected");
  }
}

Testing

Open the serial monitor to get the assigned IP address, in your favourite web browser navigate to this IP address

This is my example

 

esp32 webpage

esp32 webpage

Now press the on and off button and check if the LED flashes

Links

You can pick up a module for about $8

Official DOIT ESP32 Development Board WiFi+Bluetooth Ultra-Low Power Consumption Dual Core ESP-32

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Tutorials

Basic analog test example for an ESP32 board

by shedboy71

This is a very basic example for the ESP32 board, the only reason for this is to show that unlike the ESP8266 boards the ESP32 has more than one Analog pins – in fact it has 12 analog pins

Once you have added ESP32 support to the Arduino IDE then select the Wemos Lolin 32 board and the correct port.

Code

 

int analog0;
int analog1;
int analog2;
int analogVal0 = 0;
int analogVal1 = 0; 
int analogVal2 = 0; 

void setup() 
{
Serial.begin(9600); // use the serial port to send the values back to the computer 
}

void loop()
{
analogVal0 = analogRead(analog0); // read the value from the sensor
analogVal1 = analogRead(analog1);
analogVal2 = analogRead(analog2);

Serial.println("analogVal0"); // print the value to the serial port 
Serial.println(analogVal0);
Serial.println("analogVal1"); // print the value to the serial port
Serial.println(analogVal1);
Serial.println("analogVal2"); // print the value to the serial port
Serial.println(analogVal2);
}

 

Output

Open the serial monitor and you should see something like this

analogVal0
404
analogVal1
384
analogVal2
364
analogVal0
416
analogVal1
393
analogVal2
368

 

Link

WEMOS LOLIN32 V1.0.0 Wifi Bluetooth Board ESP-32 4MB Flash

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Tutorials

Adding support for ESP32 boards

by shedboy71

This is  the github instructions, I have been looking at the ESP32 module

My ESP Arduino installation is located at J:\esp on my PC but other than changing the paths everything went as planned. The board I bought was a Lolin32 from Wemos – we'll come to that later

Tested on 64 bit Windows 10 machine (I don't have 32 Bit)

  1. Download and install the latest Arduino IDE Windows Installer from arduino.cc
  2. Download and install Git from git-scm.com
  3. Start Git GUI and run through the following steps:
    • Select Clone Existing RepositoryStep 1
    • Select source and destination
      • Source Location: https://github.com/espressif/arduino-esp32.git
      • Target Directory: C:/Users/[YOUR_USER_NAME]/Documents/Arduino/hardware/espressif/esp32
      • Change this to your Sketchbook Location if you have a different directory listed underneath the “Sketchbook location” in Arduino preferences.
      • Click Clone to start cloning the repositoryStep 2 Step 3
    • Open C:/Users/[YOUR_USER_NAME]/Documents/Arduino/hardware/espressif/esp32/tools and double-click get.exeStep 4
    • When get.exe finishes, you should see the following files in the directoryStep 5
  4. Plug your ESP32 board and wait for the drivers to install (or install manually any that might be required)
  5. Start Arduino IDE
  6. Select your board in Tools > Board menu
  7. Select the COM port that the board is attached to
  8. Compile and upload (You might need to hold the boot button while uploading)Arduino IDE Example

How to update to the latest code

  1. Start Git GUI and you should see the repository under Open Recent Repository. Click on it!Update Step 1
  2. From menu Remote select Fetch from > originUpdate Step 2
  3. Wait for git to pull any changes and close Git GUI
  4. Open C:/Users/[YOUR_USER_NAME]/Documents/Arduino/hardware/espressif/esp32/tools and double-click get.exeStep 4
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