Specifications

ii
2.7.1 Remote Access .......................................................................................................... 45
2.7.2 TCP/IP ......................................................................................................................... 46
2.7.3 Host-to-Network Layer .............................................................................................. 46
2.7.4 Internet Layer ............................................................................................................. 47
2.7.5 Transport Layer ......................................................................................................... 47
2.7.6 Application Layer ....................................................................................................... 48
2.7.7 Microchip TCP/IP Stack ........................................................................................... 48
2.7.8 Implementation .......................................................................................................... 49
2.7.9 Microchip HTTP Server ............................................................................................ 55
2.7.10 Implementation ........................................................................................................ 55
2.8 MPFS .................................................................................................................................. 58
2.9 Mobile Web Site ................................................................................................................ 60
2.10 iPhone App ...................................................................................................................... 60
2.11 Scripting Languages ...................................................................................................... 61
2.11.1 PHP ........................................................................................................................... 61
2.11.2 CGI ............................................................................................................................ 61
2.11.3 JavaScript ................................................................................................................. 61
2.11.4 HTML ........................................................................................................................ 61
2.12 Power ............................................................................................................................... 62
2.12.1 Main Control Unit / LCD Touch Screen User Interface ..................................... 62
2.12.2 Remote Sensing Unit .............................................................................................. 62
2.13 Batteries ........................................................................................................................... 63
2.14 HVAC Environmental Factors ...................................................................................... 64
2.15 Dampers .......................................................................................................................... 65
2.16 Sensors ............................................................................................................................ 68
Section 3: Design ........................................................................................................................ 74
3.1 Software Design ............................................................................................................... 74
3.2 Wireless Communication ................................................................................................. 75
3.2.1 IEEE 802.15.4 2.4 GHz RF Transceiver Module (MRF24J40MB) .................. 75
3.2.2 IEEE 802.11b™ RF Transceiver Module (MRF24WB0MA) ............................... 78
3.3 Temperature and Relative Humidity Sensor ................................................................ 81
3.3.1 Sensirion SHT21 ....................................................................................................... 81
3.3.2 Sensirion SHT21 and the I
2
C Protocol ................................................................... 82
3.4 Evervision LCD Panel ...................................................................................................... 84
3.4.1 Environmental Conditions for Evervision LCD Panel .......................................... 86