1. Bluetooth Low Energy Environmental Sensor
Nicholas Bertoldi, Nathan Jones, Caleb Pratt, Scott Su
{bertoldi, jonesnl, calpratt, scottxsu} @ umich.edu
EECS 373
Design of Microprocessor-Based Systems
Bluetooth Low Energy SQUALL Goal
• Part of the Bluetooth 4.0 Specification
• Two modes of operation
• Connections
• Connectionless Broadcasts
• Lower energy usage
• Same distance as normal Bluetooth
• Lower data rate than normal Bluetooth
• Devloped at the University of Michigan’s Lab 11
• BLE Sensor Tag
• Designed to be inexpensive
• Create a sensor board for the SQUALL
• Measure temperature, humidity, light, and pressure
• Advertise sensor data
• Create an android app to monitor the sensor data
• Record the data on a webserver for later use
Introduction
Sensor Platform Android Application Server
• SQUALL board
• Custom daughter board with sensors
• Light
• Temperature and Humidity
• Pressure
• Advertises sensor data at regular intervals
• Listens for sensor data
from nearby BLEES
platforms
• Pushes sensor data
received to a server
• Supports multiple
simultaneous BLEES
platforms
• Stores all sensor data reported from the Android app for
each BLEES platform
• Creates visualizations of data vs. time
Project
Energy Reductions Energy Profile
Measurements every 10 seconds | Broadcasts every 500 ms
• 200 μA drawn on average
• 45.76 days on a 220 mAh battery
Measurements every minute | Broadcasts every second
• 133 μA drawn on average
• 69.02 days on a 220 mAh battery
Power
https://github.com/BLEES
Figure 3. Screenshot of the BLEES monitoring websiteFigure 2. Screenshot of the BLEES Android
application
Figure 1. SQUALL design
Figure 4. Oscilloscope outputs showing reduced energy consumption when
sensors are disabled between sensor readings (below) instead of running con-
tinuously (above).
Figure 5. Oscilloscope showing energy usage during a sensor polling
operation
Figure 6. Oscilloscope showing energy usage during a broadcast