LAB: ADC - IR reflective sensor

Date: 2023-11-13

Author/Partner:

Github: repository link

Demo Video: Youtube link

PDF version:

Introduction

Create a simple program that uses ADCs to use analog sensors. For this lab, we will use two IR reflective sensors.

The ADCs are triggered by a timer at the given sampling rate.

This lab will be extended to Project: Line Tracing Car

You must submit

• LAB Report (*.md & *.pdf)

• Zip source files(main*.c, ecRCC.h, ecGPIO.h, ecSysTick.c etc...).

  • Only the source files. Do not submit project files

Requirement

Hardware

• MCU

  • NUCLEO-F411RE

• Actuator/Sensor/Others:

  • IR Reflective Sensor (TCRT 5000) x2

Software

• Keil uVision, CMSIS, EC_HAL library

Problem 0: STM-Arduino

Procedure

1. Create a new project under the directory\repos\EC\LAB\LAB_ADC

2. Follow the tutorial: ADC with photodector and sound sensor

Tutorial: arduino-stm32 Part2 | EC

Problem 1: EC library

Using HAL library

Download

• ecADC2_student.c

• ecADC2_student.h

Change the file names as

• ecADC2.c

• ecADC2.h

ecADC2.h

/////////////////////////////////////////////////////
// ADC default setting
/////////////////////////////////////////////////////

// ADC init
// Default:  one-channel mode, continuous conversion
// Default: HW trigger - TIM3 counter, 1msec
void ADC_init(PinName_t pinName);
void JADC_init(PinName_t pinName);


// Multi-Channel Scan Sequence 
void ADC_sequence(PinName_t *seqCHn, int seqCHnums); 
void JADC_sequence(PinName_t *seqCHn, int seqCHnums); 

// ADC start
void ADC_start(void);

// flag for ADC interrupt
uint32_t is_ADC_EOC(void);
uint32_t is_ADC_OVR(void);
void clear_ADC_OVR(void);

// read ADC value
uint32_t ADC_read(void);




/////////////////////////////////////////////////////
// Advanced Setting
/////////////////////////////////////////////////////
// Conversion mode change: CONT, SINGLE / Operate both ADC,JADC
void ADC_conversion(int convMode); 					
void ADC_trigger(TIM_TypeDef* TIMx, int msec, int edge);

// Private Function
void ADC_pinmap(PinName_t pinName, uint32_t *chN);

Fill-In missing code in ecADC2_student.c

You must update your header files in the directory EC\include\. and add in ecSTM32F4v2.h

ecADC2_student.c

void ADC_init(PinName_t pinName){
// ...
// ...
	// 2. Regular / Injection Group 
	//Regular: SQRx, Injection: JSQx

	// 3. Repetition: Single scan or Continuous scan conversion
	ADC1->CR2 |= ___________;      			// default : Continuous conversion mode	
	
	// 4. Single(one) Channel or Scan(multi-channel) mode  
	// Configure the sequence length		// default: one-channel length
	ADC1->SQR1 &= ___________; 				// 0000: one channel length in the regular channel conversion sequence
	
	// Configure the multiple channel sampling sequence 
	ADC1->SQR3 &= ~ADC_SQR3_SQ1;			// SQ1 clear 
	ADC1->SQR3 |= ___________; 				// Choose the first channelID to sample
	
	// Default:  Single(one-channel) Channel mode 
	ADC1->CR1 &= ___________;				// 0: One-channel mode 		
	
	// 5. Interrupt Enable
	// Enable EOC(conversion) interrupt. 
	ADC1->CR1 &= ~ADC_CR1_EOCIE;          	// Interrupt reset
	ADC1->CR1 |= ___________;           	// Interrupt enable
	
// ...
// ...
}

ecADC2_student.c

void JADC_init(PinName_t pinName){
// ...
// ...
	// 2. Injection Group 
	//    Injection: JSQx

	// 3. Repetition: Single or Continuous conversion
	ADC1->CR2 |= _____________;     		// Enable Continuous conversion mode	
	
	// 4. Single Channel or Scan mode
	//  - Single Channel: scan mode, right alignment	
	ADC1->CR1 |= _____________;			// 1: Scan mode enable 
	ADC1->CR2 &= _____________;   			// 0: Right alignment	

	// Configure the injected channel sequence length
	ADC1->JSQR &= _____________; 			// 00: conversion in the inject channel

	// Configure the injected channel sequence 
	ADC1->JSQR &= ~ADC_JSQR_JSQ1;			// SQ1 clear bits
	ADC1->JSQR |= _____________; 			// Choose the channel to convert firstly

	// 5. Interrupt Enable
	// Enable JEOC(conversion) interrupt.
	ADC1->CR1 &= ~ADC_CR1_JEOCIE;   		// JEOC interrupt reset
	ADC1->CR1 |= _____________;			// JEOC interrupt enable
		
// ...
// ...
}

Example Code

Check your library files by running the following examples.

Example 1: One Analog sensor (ADC)

• Single-Channel, Continuous Scan

• 1msec ADC triggering with TIM3

#include "ecSTM32F4v2.h"
// #include "ecADC.h"


//IR parameter//
uint32_t value;

void setup(void);
	
int main(void) { 
	
	// Initialiization --------------------------------------------------------
	setup();
	
	// Inifinite Loop ----------------------------------------------------------
	while(1){
		printf("value = %d \r\n",value);
		printf("\r\n");
		delay_ms(1000);
	}
}

// Initialiization 
void setup(void)
{	
	RCC_PLL_init();		// System Clock = 84MHz
	UART2_init();		// UART2 Init
	SysTick_init();		// SysTick Init
	ADC_init(PB_0);		// Default: HW triggered by TIM3 counter @ 1msec
}

// ADC Interrupt
void ADC_IRQHandler(void){
    if(is_ADC_OVR())
		clear_ADC_OVR();

	if(is_ADC_EOC())
		value = ADC_read();
}

Example 2: Multiple Analog sensors (JADC)

• Multi-Channel(2 channels), Continuous Scan

• 1msec ADC triggering with TIM3

• (ADC) Channel Sequence: SQ1=ADC_CH_8(PB_0) to SQ2=ADC_CH_9(PB_1)

• (JADC): Channel Sequence: JSQ1=ADC_CH_8(PB_0)(PB_0) to JSQ1=ADC_CH_9(PB_1)

Use JADC instead of ADC for multiple-channel ADC

JADC

JADC: Has its own data register for each ADC channels

#include "ecSTM32F4v2.h"
// #include "ecADC.h"

//IR parameter//
uint32_t value1, value2;
PinName_t seqCHn[2] = {PB_0, PB_1};

void setup(void);

int main(void) { 
	// Initialiization --------------------------------------------------------
	setup();
	
	// Inifinite Loop ----------------------------------------------------------
	while(1){
		printf("value1 = %d \r\n",value1);
		printf("value2 = %d \r\n",value2);
		printf("\r\n");
		
		delay_ms(1000);
	}
}

// Initialiization 
void setup(void)
{	
	RCC_PLL_init();                 // System Clock = 84MHz
	UART2_init();			// UART2 Init
	SysTick_init();			// SysTick Init
	
	// ADC Init  Default: HW triggered by TIM3 counter @ 1msec
	JADC_init(PB_0);
	JADC_init(PB_1);

	// ADC channel sequence setting
	JADC_sequence(seqCHn, 2);
}


void ADC_IRQHandler(void){
	if(is_ADC_OVR())
		clear_ADC_OVR();
	
	if(is_ADC_JEOC()){		// after finishing sequence
		value1 = JADC_read(1);
		value2 = JADC_read(2);
	}
}

ADC

ADC: Shares the same data register from multiple channels

#include "ecSTM32F4v2.h"
// #include "ecADC.h"

//IR parameter//
uint32_t value1, value2;
int flag = 0;
PinName_t seqCHn[2] = {PB_0, PB_1};

void setup(void);

int main(void) { 
	// Initialiization --------------------------------------------------------
	setup();
	
	// Inifinite Loop ----------------------------------------------------------
	while(1){
		printf("value1 = %d \r\n",value1);
		printf("value2 = %d \r\n",value2);
		printf("\r\n");
		
		delay_ms(1000);
	}
}

// Initialiization 
void setup(void)
{	
	RCC_PLL_init();                         // System Clock = 84MHz
	UART2_init();				// UART2 Init
	SysTick_init();				// SysTick Init
	
	// ADC Init  Default: HW triggered by TIM3 counter @ 1msec
	ADC_init(PB_0);
	ADC_init(PB_1);

	// ADC channel sequence setting
	ADC_sequence(seqCHn, 2);
}


void ADC_IRQHandler(void){
	if(is_ADC_OVR())
		clear_ADC_OVR();
	
	if(is_ADC_EOC()){		// after finishing sequence
		if (flag==0)
			value1 = ADC_read();  
		else if (flag==1)
			value2 = ADC_read();
			
		flag =! flag;		// flag toggle
	}
}

Problem 2: Measurement from multiple analog sensors

IR Reflective Sensors (TCRT 5000)

First, download and read IR Reflective Sensor(TCRT 5000): Spec Sheet

TCRT5000 and TCRT5000L are reflective sensors that include an infrared emitter and phototransistor in a leaded package which blocks visible light.

image

The HC-SR04 Ultrasonic Range Sensor Features:

• Input Voltage : 5V

• Detector type: phototransistor

• Operating range within > 20 % relative collector current: 0.2 mm to 15 mm

• Emitter wavelength: 950 nm

APPLICATIONS

• Position sensor for shaft encoder

• Detection of reflective material such as paper, IBM cards, magnetic tapes etc.

• Limit switch for mechanical motions in VCR

Procedure

1. Create a new project under the directory \repos\EC\LAB\LAB_ADC

• The project name is “LAB_ADC_IR”

• Create a new source file named as “LAB_ADC_IR.c”

You MUST write your name on the source file inside the comment section.

2. Update and use ecSTM32F411.h. This header should be defined as explained in

Configuration

Type	Port - Pin	Configuration
System Clock		PLL 84MHz
GPIO	PB_0 PB_1	Analog Mode No Pull-up Pull-down
ADC (JADC)	PB_0: ADC1_CH8 (1st channel) PB_1: ADC1_CH9 (2nd channel)	ADC Clock Prescaler /8 12-bit resolution, right alignment Continuous Conversion mode Scan mode: Two channels in regular group External Trigger (Timer3 Trigger) @ 1kHz Trigger Detection on Rising Edge
TIM3		Up-Counter, Counter CLK 1kHz OC1M(Output Compare 1 Mode) : PWM mode 1 Master Mode Selection: (Trigger) OC1REF

Line Tracing

line

• Create a logic to trace a dark line on white background surface for your RC car.

• Use 2 IR reflective sensors to detect if the black line is in between the sensors. It should display whether the system needs to move Left or Right to keep the line between sensors.

• Set the ADC sampling rate trigger to be 1KHz

• Determine the threshold value to differentiate dark and white surface of the object.

• Display (1) and (2) on serial monitor of Tera-Term. Print the values every second.

  ​ (1) reflection value of IR1 and IR2

  ​ (2) print ‘GO LEFT’ or ‘GO ‘RIGHT’

Display Example

image

Circuit Diagram

You need to include the circuit diagram

image

Discussion

1. How would you change the code if you need to use 3 Analog sensors?

Answer discussion questions

1. Which registers should be modified if you need to use Injection Groups instead of regular groups for 2 analog sensors?

   Answer discussion questions

Code

Your code goes here: ADD Code LINK such as github

Explain your source code with necessary comments.

// YOUR MAIN CODE ONLY
// YOUR CODE

Results

Experiment images and results

Show experiment images /results

Add demo video link

Reference

Complete list of all references used (github, blog, paper, etc)

Troubleshooting

(Option) You can write Troubleshooting section