1. ReTemp : REMOTETEMPERATURECONTROLLER Group Members: Kenny Chung Chung Wai kxc5979@rit.edu Amish Rughoonundon axr0284@rit.edu Instructor: Dr. Roy Czernikowski Description: Hardware Interface: User Interface: RIT Computer Engineering Senior Design Project Fall 2004 Software: Retemp allows an individual to control the temperature of a house or a room. The internet is used as a medium to permit a user to remotely change the current temperature of a building as well as observe the current indoor and outdoor temperature. The heating and cooling devices are controlled by the Motorola 68HC12 micro-controller, which communicates with the PC using an RS-232 cable. Hardware Schematics: Heating System Cooling System Sensing System Cost Analysis : Java Interface HC12 Micro-controller Lamp control state The login page of the user interface is accessed at http://retemp.rh.rit.edu. After the proper username and password have been validated, the temperature controller is displayed. It consists of 2 parts: Main controller: The user can adjust the current indoor temperature in degree Celsius or Fahrenheit Scheduler: The scheduler window is opened using the Open Temperature Scheduler button. This allows the user to set two different schedule as well as clear any schedule previously set. Equal stateFan control state If the wanted temperature is higher than the current temperature, the lamp will increase the temperature until the wanted temperature plus one degree is reached. The lamp will then turn off and let the cold seep in cooling the temperature to the wanted level. If the wanted temperature is lower than the current temperature, the fan will decrease the temperature until the wanted temperature plus one degree is reached and then turn off to allow the cold to seep in cooling the temperature to the wanted level. This is shown in figure 1 If the wanted temperature is higher than the current temperature, the lamp will increase the temperature until the wanted temperature minus one degree is reached. The lamp will then turn off and let the heat seep in heating the temperature to the wanted level. If the wanted temperature is lower than the current temperature, the fan will decrease the temperature until the wanted temperature plus one degree is reached and then turn off to allow the cold to seep in cooling the temperature to the wanted level. This is shown in figure 2 If the wanted temperature is higher than the current temperature, the lamp will increase the temperature until the wanted temperature minus one degree is reached. The lamp will then turn off and let the heat seep in heating the temperature to the wanted level. If the wanted temperature is lower than the current temperature, the fan will decrease the temperature until the wanted temperature minus one degree is reached and then turn off to allow the heat to seep in heating the temperature to the wanted level. This is shown in figure 3 Wanted temperature Wanted temperature plus one Wanted temperature minus one Test lower limit Turn off lamp and fans Test Higher limit Turn on lamp Turn on fans Wanted temperature Wanted temperature plus one Wanted temperature minus 1 Turn off lamp and fans Turn on fans Turn on lamp Wanted temperature Wanted temperature plus one Wanted temperature minus one Test lower limit Turn on fans Test Higher limit Turn off lamp and fans Turn on lamp Figure 1: Lamp control stateFigure 2: Equal control stateFigure 3: Fan control state The heating system consists of a light bulb triggered by the Port 0 through the Solid State Relay The cooling system consists of two fans, one extracting the hot air and one blowing cold air in. The sensing system consists of three linear thermistors: two are placed indoor to measure the average temperature, one is placed outdoor to measure the outside temperature.