Programming with ESP32 Lolin D32

Purchasing

This video does a good job explaining which ESP32 to buy: https://www.youtube.com/watch?v=mnoZYlyebBc&t=602s. For prototyping, I’m picking the Lolin D32 because of its low power draw and use in breadboarding https://docs.google.com/spreadsheets/d/1Mu-bNwpnkiNUiM7f2dx8-gPnIAFMibsC2hMlWhIHbPQ/edit

Install

1. Download Arduino IDE: https://www.arduino.cc/en/software
2. Go to File>Preferences and drop https://dl.espressif.com/dl/package_esp32_index.json into libraries
3. Go to board manager, type in ESP 32, and install
4. Download CH340 Driver: https://learn.sparkfun.com/tutorials/how-to-install-ch340-drivers/
5. Get a 100uF capacitor and connect from EN to ground pin https://randomnerdtutorials.com/solved-failed-to-connect-to-esp32-timed-out-waiting-for-packet-header/
6. Test out a variety of usb cables until one works (the shorter the better)

Testing

1. go to Tools > board > ESP32 Arduino > select the Lolin D32 Board
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2. select the Tools > Port > whichever COM port is available
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3. upload a blank sketch (File > New)
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4. Try uploading the SimpleTime sketch
   • Open: File > Examples > ESP32 > Time > Simple Time
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5. Put in your Wifi/password
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6. Put in your GMT offset
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7. Upload
8. Go to Tools > Serial Monitor
9. Tada

Pins

Check out this spreadsheet for what pins to use https://drive.google.com/file/d/1gbKM7DA7PI7s1-ne_VomcjOrb0bE2TPZ/view. This video helps explain it https://www.youtube.com/watch?v=LY-1DHTxRAk.

I2C (SDA/SCL)

For I2C connections, SDA pins of the microcontroller connect to SDA pins on the sensor, and likewise SCL connects to SCL. On the ESP32:

• SDA: GPIO21
• SCL: GPIO 22

Programming

Asyncrhonous Webserver

This website is a treasure trove of good info on programming with the ESP32 https://randomnerdtutorials.com/getting-started-with-esp32/. However, if you want to control things from your computer/phone or see sensor input, here’s the steps:

1. Download the AsyncTSP library: https://github.com/me-no-dev/AsyncTCP
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2. Download the ESPAsyncWebServer: https://github.com/me-no-dev/ESPAsyncWebServer
3. Unzip both files
4. Drag into your Arduino Library Folder.
   • In my case, my Arduino folder was in my Documents folder, so the path was: C:\Users\Username\Documents\Arduino\libraries, but your path might be slightly different depending on where it’s located.
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Troubleshooting

Com port not showing up

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  1. open up device manager and check with ESP32 plugged in
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  1. Now check without ESP32 but micro USB cable left in computer. If you don’t notice a difference, try a different USB cable OR try putting your laptop in full power mode (not battery saver).
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  1. Download CH340 Driver: https://learn.sparkfun.com/tutorials/how-to-install-ch340-drivers/all
  2. Install
  3. Restart Computer
  4. Tada

     Error uploading

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  1. Try new usb cable
  2. Try putting 100 uF capacitor from the enable pin to the ground pin. This tutorial suggests a 10uF capacitor, but I’ve found a 100uF cap works better: https://randomnerdtutorials.com/solved-failed-to-connect-to-esp32-timed-out-waiting-for-packet-header/