Final Project: Light Source & Object Proximity Detector System

DCS Course
A comprehensive embedded system and PC interface for detecting light sources and object proximity using an MSP430 MCU.

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🛠 Hardware Architecture

• Layering: BSP → HAL → API/APP → main (FSM, interrupt-driven)
• I/O: UART 9600 bps
• Display: LCD 16×2
• Sensors: HC-SR04 (Ultrasonic) + two LDRs (Light Dependent Resistors)
• Motor: SG90 servo motor

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📍 Pin Out

Pin	Function	Description
P1.0	Analog Input (A0)	LDR1 Signal
P1.1	UART	RXD
P1.2	UART	TXD
P1.3	Analog Input (A3)	LDR2 Signal
P1.4	Digital Output	LCD Data D4
P1.5	Digital Output	LCD Data D5
P1.6	Digital Output	LCD Data D6
P1.7	Digital Output	LCD Data D7
P2.0	Digital Input	PB0 (LDR Calibration Button)
P2.1	Digital Output	LCD Control Signal (E)
P2.2	Timer A1 CCR1	Ultrasonic Sensor Output (ECHO)
P2.3	Digital Output	LCD Control Signal (RS)
P2.4	Timer A1 CCR2	PWM Out (Servo Motor Control)
P2.5	Digital Output	LCD Control Signal (RW)
P2.6	Timer A0 CCR1	Ultrasonic Sensor Input (TRIG)
P2.7	Digital Input	PB1

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📂 Source Index

MCU (C)

• Headers: app.h, api.h, halGPIO.h, bsp_msp430x2xx.h
• Sources: bsp.c, halGPIO.c, api.c, main.c

PC (Python)

• Main Entry: main.py
• Modules: comm/, gui/, processing/, visualization/

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🧠 MCU Subsystem Details

1. Headers

• app.h: Constants & memory map (Flash addresses, sizes), Enums (FSM states, ScanMode, FileType), FileEntry structure, extern shared states.
• api.h: APP/API prototypes for detectors, measurements, file system operations, and calibration sequences.
• halGPIO.h: HAL prototypes for LCD, UART, ADC, Timers, PWM, Ultrasonic, Flash, circular RX buffer, and LPM helpers.
• bsp_msp430x2xx.h: BSP pin mapping, general macros, Timer/ADC/UART defines, and ISR vectors.

2. C Sources

bsp.c (Board Support Package)

Low-level board bring-up and system helpers:

• GPIOconfig, Timers_Init, ADC_config, UART_init
• LPM and global IRQ utilities (enterLPM, enable_interrupts)

halGPIO.c (Hardware Abstraction Layer)

Direct hardware layer and ISRs:

• LCD: lcd_init, lcd_cmd, lcd_data, lcd_puts
• UART: UART_send_char, UartBuffer_Init/Put/Get
• Timers/Ultrasonic: Blocking delays, Ultrasonic_Start_Measurement
• PWM/Servo: pwmOutServoConfig, Set_Angle_PWM
• ADC: ADC_Enable, ADC_sample, channel configs
• Flash: Timing, erase/write operations
• ISRs: Buttons (PBs_handler), Timers (Timer_1_ISR, Timer0_A0_ISR_Handler), ADC (ADC_ISR)

api.c (APP/API Layer)

High-level logic, runtime FSMs, Flash filesystem, scripts, and scanning:

• Scans & Sensing: servo_scan, object_detector, telemeter, light_detector, light_object_detector
• LDR Calibration: run_calibration_sequence, write_all_calib_to_flash, send_calib_arr
• Filesystem: FileSystem_Init, Handle_UploadFile_Start, Handle_Upload_Byte, script interpreters (parse_and_execute_line)

main.c (Entry Point)

Initialize layers, run RX loop, decode UART commands, and dispatch FSMs.

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💻 PC Subsystem (Python)

The PC-side provides a PySimpleGUI desktop application to control all modes, run calibration, manage files, process sensor data, and plot polar maps.

Key Functionalities:

• Serial Management: UART communication wrapped in serial_manager.py.
• GUI Modules: Isolated event loops for Objects, Telemeter, Lights, Combined, and File modes.
• Processing: Signal smoothing, valley/peak detection, filtering, and crosstalk cleaning (process_light_scan_data).
• Data Visualization: Matplotlib polar plots for detected objects and light sources.
• File Upload Protocol: Handles MCU handshake, checksum generation, and 64-byte chunked flashing.

Script Opcodes:

Command	Hex	Command	Hex
inc_lcd	0x01	dec_lcd	0x02
rra_lcd	0x03	set_delay	0x04
clear_lcd	0x05	servo_deg	0x06
servo_scan	0x07	sleep	0x08

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🔌 UART Protocol Quick Reference

Control Markers:

• Start-of-Script = 0xCC
• Telemetry Header = 0xFE
• End/Sleep = 0x7F
• End-of-Scan = FF FF FF

Handshakes & Commands:

• Handshake: 'P' → MCU replies 'A'
• Objects: 'S' → stream of (2B distance + 1B angle) per step; end marker FF FF FF
• Lights: 'K' → stream of (LDR1_lo, LDR1_hi, LDR2_lo, LDR2_hi, angle)
• Combined: 'X' → stream of (2B distance, 2B LDR1, 2B LDR2, 1B angle); end marker FF FF FF
• Telemeter: 'T' + angle byte → MCU returns (2B distance + 1B angle)
• Files:
  • 'L' (List), 'U' (Upload), 'R' (Run script), 'V' (LCD view mode), 'D' (Delete FS)
• Calibration: 'J' (Guided LDR capture), 'Z' (Read back compressed array)

Note: Endianness is Little-Endian (first Low-Byte, second High-byte).

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👥 Authors

• Arkady Gerasimuk
• Adi Shlomo