PeekAlert
A smart light-based alert system with WiFi connectivity.
Author: Nour Al Houda Mahfood
GitHub: PeekAlert Repository
Description
PeekAlert is a light-activated alert system that detects unusual lighting conditions (like someone peeking through a door or curtain) and responds by sounding a buzzer, logging the event, and displaying it on an LCD. It also offers wireless connectivity to enable remote access to logs via WiFi.
Motivation
This project is inspired by the idea of privacy and awareness in shared spaces. It provides a simple yet effective way to detect and record potential intrusions or unexpected movement using only light changes.
Architecture
The project uses two Raspberry Pi Pico 2W boards, one as the main microcontroller handling all system logic, and another as a debugger. A photoresistor (LDR) is connected to an analog pin to detect ambient light changes, triggering a buzzer when suspicious activity is detected. An LCD display, connected over SPI, shows system status and alerts, while a DS3231 RTC module communicates over I2C to timestamp events. WiFi functionality is provided through the Pico's onboard CYW43 chip.
Log
- Week 5 – 11 May: Initial testing of the photoresistor and buzzer modules, and implementing flash logging.
- Week 12 – 18 May: LCD set up using SPI, and RTC integrated.
- Week 19 – 25 May: WiFi functionality implemented for remote access to logs.
Hardware
- Raspberry Pi Pico 2W (x2) – one used as microcontroller, one as debugger
- 1.8'' SPI LCD (ST7735s, 128x160)
- DS3231 RTC module (I2C)
- Active buzzer module
- 10kΩ resistor
- Breadboards (400 + 830 points)
- White 2.54mm pin headers
- Jumper wires
- Photoresistor (LDR) sensor
- 6x6x6 push buttons (2 used)
Schematics
Bill of Materials
| Device | Usage | Price in RON |
|---|---|---|
| Raspberry Pi Pico 2W (x2) | Microcontroller + Debugger | 39.66 |
| Resistor 10KΩ | Voltage divider | 0.10 |
| Push Button (x2) | Log scroll, Sync | 0.72 |
| SPI LCD Display 1.8'' | Visuals | 28.99 |
| Active Buzzer Module | Audio alert | 4.98 |
| Jumper Wire Set | Connections | 7.99 |
| White Pin Header (x2) | For the pico | 1.98 |
| Breadboard HQ 400 Points | Prototyping | 4.56 |
| Breadboard HQ 830 Points | Prototyping | 9.98 |
| Photoresistor (LDR) | Light detection | 1.90 |
| DS3231 RTC Module | Real-time clock | 18.99 |
Software
| Library | Description | Usage |
|---|---|---|
embassy-rp | RP2350 HAL with async support | Main async runtime and peripheral control |
mipidsi | Generic TFT driver | Controls the ST7735s SPI display |
embedded-graphics | Graphics primitives for embedded displays | Drawing text and logs |
ds323x | RTC interface | Interfacing with DS3231 RTC module |
heapless | Fixed-size buffer and data structures | Flash log strings and buffers |
embassy-sync | Async mutexes and primitives | SPI/I2C bus sharing |
embassy-time | Timer and delay utilities | Timed events and log delay control |
embassy-flash | Flash memory abstraction | Persistent log storage |
embassy-net, cyw43 | WiFi/network stack for remote logging | Enables wireless access to log data |
defmt + panic-probe | Debug logging and error handling | RTT logging/debug |