[Arduino Experiment Notes] Robotic Arm (1) Control the onboard LED lights to flicker

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foreword

I bought an Arduino board a long time ago, but I have been eating ashes until now. Recently, I spent time studying and found that this board is a must-have entry board for Xiaobai ( the bottom layer is highly packaged and rich in information ). Of course, although Arduino is simple, this does not affect its powerful functions. I believe that in the process of learning, you can reap the joy of creation.

I am used to recording the experiments I have done, and each chapter will introduce a kind of hardware and related functions . Combining multiple chapters is one article , and at the end of each article, a comprehensive small project will be done . It will use the knowledge learned in the previous chapters.

This is the first article , our goal is to make a robotic arm ! It's cool! So, without further ado, let's get started!

Reference ^{1 in this series}

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Introduction to Arduino

Arduino does not specifically refer to a single- chip microcomputer or a development environment , but actually refers to the entire ecosystem from software to hardware .

Arduino is developed based on Arduino IDE , the bottom layer is C language and C++ , and the hardware and code are open source . It has the characteristics of rich ecology and cross-platform .

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Arduino development board

Common development boards for Arduino include Arduino UNO , Arduino Nano , Arduino Mega 2560 , etc. This article uses the Arduino UNO R3 model development board, the important parameters are as follows:

• Chip : ATmega328P microcontroller based on Atmel
• Crystal oscillator : 16MHz
• Digital IO : 0 - 13 , output digital signal. The pin output level voltage is 5V , and the maximum output current is 40mA .
  • PWM: 3, 5, 6, 9, 10, 11 with~
  • Serial port: 0, 1
• Analog IO: A0 - A5 , with 10-bit analog-to-analog conversion channel , which is also an advantage of Arduino , with its own ADC .
• Power supply : 3.3V/5V output, the maximum output current is 150mA
• Power supply : 12V DC port power supply is recommended
• Download : Burning program
  • USB : download interface.
  • ICSP : download interface.

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Arduino IDE

Write programs in C language , and at the same time have the object-oriented thinking of C++ . Since the Arduino IDE has rich library functions and many packaged modules, it is very easy to get started. The IDE interface is as follows:

the interface is very simple, with one-click compilation and upload in the upper left corner , and a serial port debugging tool in the upper right corner .

Here is the official website link of Arduino IDE . The installation of Arduino IDE is not the focus of this article, so I won't repeat it here.

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Configure the development board and ports

Open the Arduino IDE , and then open Tools - Development Boards - Arduino AVR Boards - Arduino Uno .

Before setting the port , connect the development board with a USB data cable and connect it to the computer . Open Tools - Ports - COMx in turn . x is the port number .

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hardware introduction

LED introduction

For a detailed introduction to LED , please refer to another blog "51 MCU LED" . Because the Arduino board has a controllable LED light (silk-printed L), so this article does not need to connect an external LED to directly control it logically.

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schematic diagram

Find the silkscreen on the Arduino development board as LLFor the LEDof$L$ ,by default, the anode is connected to pin 13 of the digital IO, and the cathode is grounded (of course, the board passes through a current-limiting resistor). That is to say,We only need to control the level of pin 13 to control the LED on and off.

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Software Implementation

Programs in Arduino IDE can be written in C/C++ .

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Introduction to library functions

First, the functions in the three core libraries are introduced . Move to the official function manual for details .

• Pin output input initialization
  void pinMode(uint8_t pin, uint8_t mode)
  • pin : pin number
  • mode : pin mode
    • Output: OUTPUT
    • Input: INOUT
    • Input pull-up: INPUT_PULLUP
• digital pin write
  void digitalWrite(uint8_t pin, uint8_t val)
  • pin : pin number
  • val : level high or low
    • Low level: LOW
    • High level: HIGH
• delay function
  void delay(unsigned long ms)
  • ms : delay in milliseconds

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code

// 2022.11.12
// Author:Qiu

#define LED_L 13    // 引脚号
#define SPEED 1000  // 控制闪烁间隔1000ms

// 参数初始化，仅执行一次
void setup() {
    
    
  // 初始化数字引脚13作为输出
  pinMode(LED_L, OUTPUT);
}

// 主循环
void loop() {
    
    
  digitalWrite(LED_L, HIGH);  // 向13引脚写入高电平
  delay(SPEED);               // 等待
  digitalWrite(LED_L, LOW);   // 向13引脚写入低电平
  delay(SPEED);               // 等待
}

After the compilation is successful, upload it to the board. The experimental phenomenon is that the LED light flickers at a frequency of 1Hz.

Of course, the same implementation can be found in the examples that come with Arduino , the path is:Documentation - Examples - Basics - Blink. I suggest that you can implement it yourself first . After all, we will involve more complex applications later, and examples alone cannot meet our needs.

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Goal of the next article

We hope to control LED lights in a more advanced way , for example, add aphysical switch. See you next time!

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Summarize

Through this chapter, you have learned how to control the digital IO port to output high and low levels , and completed the LED blinking experiment with the help of the delay function .This is so important that it will be the indicator light in our future robotic arms . Please don't take this small first step lightly!

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1. Station B: Tai Chi Maker ↩︎