Fan and temperature unit
From uCtrl.net
 |  I am moving to a new location, and therefor terminating the Rack box project, my plan is to build an even bigger system based on slot-in cards in a full size rack. I'll keep you posted. Feel tree to leave a comment if you have any question. |
Contents |
Information
FTU regulates the temperature in the Rack box. The module is equipped with a LM35 temperature sensor, installed in the top of the Rack box were it's warmest. A 80x80mm fan is also mounted at the top of the box. The air intake is at the bottom and sucks air from outside the entire closet. This gives good air circulation in the Rack box. The fan is controlled using PWM, giving the fan variable speed. It's divided into three levels: 1: 1/3, 2: 2/3, 3: full. The temperature sensor is a LM35.
When actual temperature is equal to the fan temperature the fan will start on level 1, if this persists for more then 30 seconds the fan will go to level 2. If actual temperature should rise above the fan temperature the fan is set to level 3, which is the maximum. If actual temperature is equal to the alarm temperature for more then 30 seconds the alarm will be triggered. The fan can be overridden with a manual switch, or from the external input (computer). When overridden the fan level is increased by 2 levels, meaning if 0 then 2, or if 1 or 2 then 3.
Two temperatures are stored in EEPROM, fan and alarm temperature. When stored in EEPROM the unit will remember these values even trough a power loss, the values are saved about five minutes after they are changed. In this period, when the values are changed but not stored, a "E" is displayed in the right corner if the LCD display. Fan and alarm temperature can be adjusted using the (on)-off-(on) switches, one degree at the time.
I/O
Inputs
- PB3 Fan set temp +
- PB4 Fan set temp -
- PB6 Alarm set temp +
- PB7 Alarm set temp -
- PB5 Override fan switch
- PC0 Temperature (Analog)
Outputs
- PD0 LCD1
- PD1 LCD2
- PD2 LCD3
- PD3 LCD4
- PD6 LCD5
- PD7 LCD6
- PB0 Lifesignal (to MSMU2)
- PB1 Fan
- PB2 Temp alarm (to SLCU)
D-Sub 9-pin
- 0V
- +5V
- Lifesignal
- Fan
- Temp alarm
- LCD background light switch
- Override fan switch
Switches and LEDs
Switches
- (on)-off-(on), fan temp +/-
- (on)-off-(on), alarm temp +/-
- on-off, override fan
- on-off, background light LCD display
LEDs
- Green, Lifesignal
- Green with lens, fan active
- Red with lens, temp alarm
LCD Display
1234567890123456 25C F:30C A:30C* Fan & Temp Unit! SW v.2.0 JensenCorp.no System start =)
Images
 1. test |
 Casing complete |
 Switches and LEDs |
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 LCD display simulated |
 Assembly |
 Fan intake Rack box |
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 Fan Rack box |
 Fan regulator |
FTU installed in the Rack box |
Schematic drawing
Source code
The program is written in basic, using Bascom-AVR.
'-------------------------------------------------------------- ' Thomas Jensen '-------------------------------------------------------------- ' file: AVR_FTU_v_2.0 ' date: 15/03/2007 '-------------------------------------------------------------- $regfile = "M8def.dat" $crystal = 1000000 Config Watchdog = 1024 Config Portb.0 = Output Config Portb.1 = Output Config Portb.2 = Output Config Portb.3 = Input Config Portb.4 = Input Config Portb.5 = Input Config Portb.6 = Input Config Portb.7 = Input Dim Lifesignal As Integer Dim W As Word , Volt As Word , Temp As Word Dim C_vifte1 As Byte , C_vifte2 As Byte , Set_fan As Byte Dim C_alarm1 As Byte , C_alarm2 As Byte , Set_alarm As Byte Dim Alarmled As Integer , Cls_timer As Integer , Alarm_timer As Integer Dim Eeprom_save As Integer , Eeprom_fan As Eram Byte , Eeprom_alarm As Eram Byte Dim Alarm_timer2 As Integer , Fan_speed As Byte , Temp_timer As Byte Dim Fan_delay As Integer , Fan_delay2 As Integer Dim Fan_timer As Integer , Fan_timer2 As Integer Config Timer1 = Pwm , Pwm = 8 , Prescale = 1 , Compare A Pwm = Clear Up , Compare B Pwm = Clear Up Ddrb.1 = 1 Ddrb.2 = 1 Pwm1a = 255 Pwm1b = 255 Config Lcdpin = Pin , Db4 = Portd.3 , Db5 = Portd.2 , Db6 = Portd.1 , Db7 = Portd.0 , E = Portd.6 , Rs = Portd.7 Config Lcd = 16 * 2 Config Adc = Single , Prescaler = Auto , Reference = Avcc Start Adc Lifesignal = 21 Alarmled = 0 Eeprom_save = 0 C_vifte1 = 0 C_vifte2 = 0 C_alarm1 = 0 C_alarm2 = 0 Cls_timer = 50 Alarm_timer = 0 Fan_speed = 0 Fan_delay = 0 Fan_timer = 0 Temp_timer = 10 'get eeprom values Set_fan = Eeprom_fan If Set_fan > 50 Or Set_fan < 10 Then Set_fan = 30 Set_alarm = Eeprom_alarm If Set_alarm > 50 Or Set_alarm < 10 Then Set_alarm = 32 Cls Cursor Off Deflcdchar 1 , 32 , 32 , 32 , 7 , 4 , 6 , 4 , 7 'e-sign Deflcdchar 2 , 32 , 32 , 32 , 32 , 32 , 32 , 32 , 32 'blank 'slå på alarm Pwm1b = 0 Locate 1 , 1 Lcd "Fan & Temp Unit!" Locate 2 , 5 Lcd "SW v.2.0" Waitms 2000 Cls Locate 1 , 1 Lcd "JensenCorp.no" Locate 2 , 1 Lcd "System start =)" Waitms 2000 Cls Locate 1 , 5 Lcd "F:" Locate 1 , 11 Lcd "A:" Locate 2 , 1 Lcd "Fan:" Locate 1 , 1 Lcd "?C" 'slå av alarm Pwm1b = 255 Start Watchdog Main: 'cls timer If Cls_timer > 0 Then Decr Cls_timer If Cls_timer = 0 Then Cls Locate 1 , 1 Lcd Temp ; "C" Locate 1 , 5 Lcd "F:" Locate 1 , 11 Lcd "A:" Locate 2 , 1 Lcd "Fan:" Cls_timer = 50 End If 'check temp If Temp_timer > 0 Then Decr Temp_timer If Temp_timer = 0 Then W = Getadc(0) Volt = W * 5 Temp = Volt / 10 Temp_timer = 100 End If 'show set points Locate 1 , 7 Lcd Set_fan ; "C" Locate 1 , 13 Lcd Set_alarm ; "C" 'set fan If Fan_delay = 0 Then Fan_speed = 0 If Temp < Set_fan Then If Fan_delay = 0 Then Fan_speed = 0 Fan_timer = 0 End If If Temp = Set_fan And Fan_speed <> 3 Then Fan_speed = 1 Fan_delay = 600 If Fan_timer < 300 Then Incr Fan_timer If Fan_timer = 300 Then Fan_speed = 2 Fan_delay = 600 End If End If If Temp > Set_fan Then Fan_speed = 3 Fan_delay = 600 Fan_timer = 300 End If 'fan timers If Fan_delay > 0 Then Decr Fan_delay 'set fan speed If Pinb.5 = 0 Then Fan_speed = Fan_speed + 2 If Fan_speed > 3 Then Fan_speed = 3 If Fan_speed = 0 Then Pwm1a = 255 If Fan_speed = 1 Then Pwm1a = 170 If Fan_speed = 2 Then Pwm1a = 105 If Fan_speed = 3 Then Pwm1a = 0 Locate 2 , 5 Lcd Fan_speed If Pinb.5 = 0 Then Locate 2 , 7 Lcd "F" End If 'set fan temp If Pinb.3 = 1 Then C_vifte1 = 0 If Pinb.3 = 0 And C_vifte1 = 0 Then C_vifte1 = 1 Set_fan = Set_fan + 1 Eeprom_save = 3000 End If If Pinb.4 = 1 Then C_vifte2 = 0 If Pinb.4 = 0 And C_vifte2 = 0 Then C_vifte2 = 1 Set_fan = Set_fan - 1 Eeprom_save = 3000 End If 'set alarm temp If Pinb.6 = 1 Then C_alarm1 = 0 If Pinb.6 = 0 And C_alarm1 = 0 Then C_alarm1 = 1 Set_alarm = Set_alarm + 1 Eeprom_save = 3000 End If If Pinb.7 = 1 Then C_alarm2 = 0 If Pinb.7 = 0 And C_alarm2 = 0 Then C_alarm2 = 1 Set_alarm = Set_alarm - 1 Eeprom_save = 3000 End If 'set main temp_alarm If Temp >= Set_alarm And Alarm_timer < 300 Then Alarm_timer = Alarm_timer + 1 If Alarm_timer = 300 And Alarmled = 0 Then Alarmled = 6 If Temp < Set_alarm Then Alarm_timer = 0 'alarmled If Alarmled > 0 Then Alarmled = Alarmled - 1 If Alarmled = 4 Then Pwm1b = 0 If Alarmled = 1 Then Pwm1b = 255 'eeprom save If Eeprom_save > 0 Then Eeprom_save = Eeprom_save - 1 Locate 1 , 16 Lcd Chr(1) End If If Eeprom_save = 1 Then Eeprom_fan = Set_fan Eeprom_alarm = Set_alarm Locate 1 , 16 Lcd Chr(2) End If 'show timers Locate 2 , 15 Alarm_timer2 = Alarm_timer / 10 Lcd Alarm_timer2 Locate 2 , 9 Fan_delay2 = Fan_delay / 10 Lcd Fan_delay2 Locate 2 , 12 Fan_timer2 = Fan_timer / 10 Lcd Fan_timer2 'lifesignal If Lifesignal > 0 Then Lifesignal = Lifesignal - 1 If Lifesignal = 6 Then Portb.0 = 1 If Lifesignal = 1 Then Portb.0 = 0 If Lifesignal = 0 Then Lifesignal = 21 Reset Watchdog Waitms 100 Goto Main End
