Design Sketch 

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Embedded Program

  • The tracking system has an adaptive duty cycle to be efficient.
  • When the measurement is not needed, the system will go to its sleep mode.
    • In the sleep mode, the sensor (accelerometer) will be in the standby mode which is best status to save power. The Atmega328 will go to its sleep mode with only a “watchdog” timer on in order to calculate time for the duty cycle.
  • The GPRS shield will be turned on only when a message needs to be sent out because the shield consumes a lot of power (1W) when working.
  • To change the duty cycle is based on the standard deviation of the measured tilt degrees which is influenced by the wind speed.
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Power Supply System

The power supply system consist of a 7.2 V flexible solar panel, 5V Regulator/Charger Module w Li-Ion Battery, connected to the rest of our communication system (Arduino, accelerometer, and GPRS shield). The solar panel will connect to the charging circuits which will output to the Li-Ion battery and the communication system. The module provides a regulated 5V DC (300mA) output via screw terminals to power the communication system.

Design Overview

Current design consists of four parts:
  • System Management: Used to combine the system monitoring and communications.  
  • System Monitoring: Monitors the current state of the critical stop sign.  Based upon the tilt of the sign.
  • Communications: Used to send out alerts to the end-users which will reduce response time to a broken sign.
  • Power: Harvest energy (solar), Store excess energy, and supply energy to monitoring/management system.

Final Project Design Sketch

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