Using Shift Registers With The Arduino Lab 7 Procedure Read

Using Shift Registers With The Arduinolab 7aprocedure Read The Sect

Using Shift Registers with the Arduino Lab 7a: Procedure: · Read the section: 1. Chapter 12: Building and Testing a Hardware-Debounce Button Interrupt Circuit . Construct the breadboard circuit and implement the program presented as in Chapter 12 (pp.). Lab 7b: Procedure: . Read the section: 3. Chapter 7: Shifting Serial Data from the Arduino . Construct the breadboard circuit and implement the program presented as Bar Graph Distance Control in Chapter 7 (pp.). Lab 7c: Procedure: Applying the principles in Lab 7a and 7b, design the following circuit and code: . Modify the Bar Graph Distance Control circuit and program to using a photoresistor input instead of an IR distance sensor in Chapter 3 (pp. 56- 59). Modify the program to represent an illumination LED bar graph circuit. In other words, when the photoresistor detects maximum light, all of the eight LEDS light. As you dim the amount to the photoresistor, the LEDS start to turn off from right to left. . Send your code file (.ino) of the lab completed and operational as well for credit. Analysis/Discussion: . Explain what you did in the program to reverse the display of the bar graph, making the bar graph illuminate with the LEDS on and turning off as you dimmed the light. . The 74HC595 shift register is essential converting 3 inputs to 8 outputs. In your own words, how does this work? With your answers, please submit your code, a video of your circuit and any computer screenshots during its operation. Please include your Grantham ID number in the video to show your work.

Paper For Above instruction

Introduction

The utilization of shift registers, particularly the 74HC595, in conjunction with Arduino microcontrollers, provides a robust means of expanding output capabilities without requiring additional microcontroller pins. This paper explores the practical application of shift registers within various laboratory exercises, emphasizing circuit construction, programming, and the underlying principles that govern their operation. Specifically, it discusses the development of a hardware debounce circuit, serial data shifting for a bar graph display, and an innovative light-based LED array controlled by a photoresistor sensor. A comprehensive analysis of programming techniques for display reversal and an explanation of the shift register's function are included to deepen understanding.

Construction of Hardware Debounce Circuit and Interrupts

The initial laboratory exercise involved building a hardware debounce circuit for a momentary push button using a 74HC14 hex inverter Schmitt trigger in conjunction with Arduino. The purpose was to eliminate contact bounce that causes multiple signals from a single press. During construction, the circuit was assembled on a breadboard following schematics from Chapter 12. The microcontroller program incorporated an interrupt service routine that triggered on button press, demonstrating how hardware debouncing can complement software strategies for reliable input detection. The importance of stable signals in responsive systems is highlighted.

Serial Data Shifting and Bar Graph Control

The second exercise revolved around serial data transmission from an Arduino to multiple LEDs via a shift register, specifically the 74HC595. The circuit connected the data, clock, and latch pins of the shift register to the Arduino. The implemented program utilized serial shifting commands to control a series of LEDs, creating a bar graph that visually represented distance measurements or other analog inputs. The code carefully managed timing and latch controls to accurately reflect sensor inputs or user commands, illustrating how shift registers efficiently expand output lines.

Design and Modification of Light-Responsive LED Bar Graph

Building upon the previous exercises, the third task required integrating a photoresistor to replace the IR distance sensor in controlling an LED bar graph. The program was modified to read analog values from the photoresistor, which varied according to ambient light intensity. When maximum light was detected, all LEDs lit, indicating full brightness. Conversely, as light dimmed, LEDs turned off sequentially from right to left, creating a dynamic, dimmable illumination display. The programming logic inverted the usual control scheme by reversing the LED order, providing visual feedback correlated with ambient light levels.

Programming Reversal of Display and Shift Register Functionality

The program responsible for controlling the LED display employed bit manipulation techniques to reverse the order of LED activation. Specifically, it used bitwise operations such as shifting and reversing bits within a byte to invert the display pattern. This approach ensured that higher analog readings resulted in all LEDs lit, and lower readings caused LEDs to turn off from right to left, contrary to the default left-to-right sequencing.

The 74HC595 shift register effectively converts a few microcontroller pins into multiple outputs by serially receiving data and transforming it into parallel outputs. Internally, the shift register contains a cascade of flip-flops that store serial data bits, shifting them upon each clock pulse. When the latch pin is activated, these stored bits are presented simultaneously on the output pins, thereby controlling multiple LEDs with minimal microcontroller connections.

Analysis of Shift Register Operation

In essence, the 74HC595 functions as a serial-in, parallel-out memory device. It accepts serial data through the data pin, which is shifted into internal flip-flops with each clock pulse. Once the desired pattern is loaded, activating the latch pin updates the outputs instantly. This process allows operators to control multiple outputs with just three pins, significantly simplifying circuit complexity and wiring.

The internal architecture of the 74HC595 includes a series of connected flip-flops that pass data along with each clock pulse. The serial data aligns with the output bits after a series of shifts, enabling synchronized control over all connected LEDs or other devices. This mechanism underscores its utility in expandability and efficient control schemes in microcontroller-based projects.

Conclusion

Applying shift registers like the 74HC595 in Arduino projects demonstrates their versatility and efficiency in expanding output capacity, supporting complex visual indicators, and managing multiple inputs with limited microcontroller pins. Through constructing debounce circuits, controlling LED bar graphs, and integrating sensors like photoresistors, users gain practical insights into embedded system design. The programming techniques for display inversion and the internal logic of the shift register highlight fundamental digital electronics principles, reinforcing their importance in modern hardware development.

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