LTR390-UV Sensor with Arduino

What you need:
1 X LTR390-UV Sensor
1 X Arduino UNO
1 X USB Cable

Pinout for LTR390-UV Ultraviolet Sensor (C):

Connection for LTR390-UV Sensor with arduino UNO:


Download code from this link:

Waveshare_UV_C is Arduino code, zip the file

Add the file to the Arduino IDE (Sketch-Include Library-Add .ZIP Library)


Choose board, COM port, upload code
After the code uploaded successfully, you can find the result in monitor:

Youtube link:

Purchase link:

Espressif ESP32-C3 Works with Arduino IDE

Install ESP32-C3 in your arduino IDE
1, click File-Preference, and copy below links to “Arduino Preferences Additional Boards Manager URLs”, then click “OK”.

2, Click Tools-Board-Boards Manager, and search ESP32, you need download 2.0.0 version, (any version over 2.0.0 is ok)

Testing ESP32-C3:
1, Connect ESP32-C3 board with Mac or PC

2, Choose Tools-Board-ESP32 Arduino-ESP32C3 Dev Module
3, Choose Port

4, Upload code: File-Examples-WiFi-WiFiScan

5, Open Serial Monitor window, then you will find the wifi names.

Purchase link:

1, ESP32-C3-DevKitC-02 Development Board with ESP32-C3-WROOM-02 module:

2, ESP32-C3-DevKitM-1 Development Board with ESP32-C3-MINI-1 module



DIYmall 4×4 Matrix Key Membrane Switch Keypad


What you need:
1 X 4×4 Membrane Switch Keypad
1 X Arduino Uno
1 X Jumper wires
1 X USB cable

4X4 Matrix Array Keypad Schematic

The wiring of 4X4 Keyboard with Arduino UNO R3 board is like the following picture:

You need install Keypad in your arduino IDE library if you not installed it before.

Click Sketch-Include Library-Manage Libraries, search “Keypad” and install it.

Open examples-Keypad and revise the code

#include <Keypad.h>

const byte ROWS = 4; //four rows
const byte COLS = 4; // four columns
char keys[ROWS][COLS] = {
{‘1′,’2′,’3’, ‘A’},
{‘4′,’5′,’6’, ‘B’},
{‘7′,’8′,’9’, ‘C’},
{‘*’,’0′,’#’, ‘D’}
byte rowPins[ROWS] = {9, 8, 7, 6}; //connect to the row pinouts of the keypad
byte colPins[COLS] = {5, 4, 3, 2}; //connect to the column pinouts of the keypad

Keypad keypad = Keypad( makeKeymap(keys), rowPins, colPins, ROWS, COLS );

void setup(){

void loop(){
char key = keypad.getKey();

if (key){

Choose board, COM port, and upload the code.


Open Serial Monitor window, and press the keyboard, the relative name of the pressed button will appear.

Here is the vedio link for your reference:


Purchase link for 4X4 Matrix Keypad:





Official website:

Nextion Editor, Nextion Editor LTS

Download link:

— If your HMI project was developed via 0.53 or prior version Nextion Editor, we recommend you to use the LTS version for project maintenance as the latest 1.63.3 version is not fully compatible with your existing source code and GUI design.

Document link:

Where to buy: