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IR Remote Lamp Controller
Thomas ChiaProject Description
Western Washington University2006-2007
Introduction
The IR remote control has become a family room staple since its commercial production in the
1950’s. From televisions to cable boxes, people instinctively reach for the remote for the
operation of these devices because of its added convenience and efficiency. But one device
found in the living room that is still controlled manually is the light source. Therefore the
proposed project is an IR remote lamp controller unit. A standard lamp using an incandescent
light bulb can be plugged into the unit and the unit will then plug into the wall outlet. The user
will then be able to turn the lamp on and off, control its brightness and set a sleep timer with a
standard IR remote. In the idle state the unit will display the time since it must be in plane sight
of the user. This unit should add another level of convenience to the family room that is long
overdue.
Functional Description
A preliminary sketch of the unit is shown in figure 1. As can be seen from figure 1 the unit will
at least be able to be housed in an eight-inch long, five-inch wide and four-inch tall box. As
mentioned above the lamp will plug into the unit and the unit will have a cord feeding to the AC
main. Figure 2 shows the back view of the unit showing these power cord connections. From
the IR remote, the unit will only respond to volume up/down, power, and sleep commands; all
other commands will be ignored. The unit should be placed in a location with a clear line of
sight to the user since it will display the current time when idle and can be controlled via an IR
remote.
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IR Reciever4 inches
5 inches
8 inchesFrom Lamp
2
7 Segment Display
To Wall Outlet
On/Off
Sleep FunctionBrighter/Dimmer(Hours)/(Minutes)
Figure 1. Preliminary sketch of the IR Remote Lamp Controller with maximum housing dimensions
Clock Set
Figure 2, Back view of the IR Remote Lamp Controller
Hardware Description
The project will be implemented using the MC9S12C32 microcontroller. This microcontroller
was primarily chosen because of its availability and familiarity. With 32Kbytes of flash and
2Kbytes of RAM, it should provide ample room for software development; though designing the
code for portability and efficiency will still be a top priority. The seven segment display will be
implemented using the SPI. Figure 5 shows a functional block diagram of the project.
Lamp Cord Input
To AC Main
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Figure 5. Functional block diagram
IR Receiver
As can be seen from figure 5 the IR receiver module will be connected to port T bit 0.
The output of the IR receiver module will be in digital form ready to be processed by the MCU.
There are many coding protocols for IR remote controls depending on the company. I will use
the RC5 protocol from Phillips. I chose this protocol because it is one of the older and more
widely used IR protocols. The RC5 protocol modulates a carrier frequency of 36MHZ in what is
known as bi-phase coding. Figure 6 illustrates this protocol. As can be seen, bi-phase coding
32K Flash
XTAL
2K RAM
SPI
MC9S12C128
PT1
PT0
VDDVSS
AN00-AN04
AC to DC Power Supply
IR Receiver
Dimmer Circuitry
5 Push Buttons
LED Driver
8MHz XTAL
Lamp
AC Main
PT2Zero- Crossing Detection Circuitry
7-Segment Display
Real Time Clock
Neutral
NeutralHot
HotEarth Ground
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has a constant bit length and a 50% duty cycle. The second part of the bit represents the logical
“1” or “0”. The first two bits are the start bits and are always high. The third bit is a toggle bit,
which only changes if a button was pressed and released, thus holding a key down will only
execute the command once. The next 5 bit lengths are the address and the last 6 bit lengths are
the command. I will use the TV2 address for the receiver since there is a sleep button on most
television remotes, which can be used for the sleep command for the project.
Figure 6. The RC5 protocol
Lamp Dimmer
The lamp dimmer functionality will be implemented using a triac to control the conduction angle
of the lamp. A normal lamp’s conduction angle is 180° for half of the 60Hz AC waveform, so it
conducts all the time. By making the conduction angle smaller the average power supplied is
smaller, thus the amount of light the light bulb emits will also be less. The MCU can be
synchronized to the AC line whenever the voltage a across the triac is zero. This
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synchronization will be accomplished by polling PTAD0 (which will be connected to the AC
main via a zero-detection circuit) for a voltage that falls within a specified range of zero.
Power
The MCU will be powered via the AC line though a voltage regulator circuit that will provide a
regulated 5V DC power supply. This circuit will consist of a step down transformer, bridge
rectifier, smoothing capacitors and a 5V voltage regulator IC.
The dimmer circuitry and thus the lamp will be powered directly by the AC mains. The
maximum voltage to the lamp will be a little less then the full 120VAC since it will be powered
through the traic. The max current for the MCU and its peripherals is estimated to be about
268mA, and for a 60W incandescent light bulb the max current is about 785.4mA. This gives a
total system max current of about 1.05A.
Seven-Segment Display
The seven-segment display will be a 4 digit clock driven by an LED diver. The LED driver is
controlled using the SPI.
Software
There will be four major software components to this project. The first is interpreting the IR
signals using the RC5 protocol mentioned above. The second will be the dimming control of the
lamp using the triac. The third will be implementing the real time clock. The fourth will be the
seven-segment display module. These modules will be written in C and assembly using the
UCOS-II kernel and its modules.
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User Interface
In idle mode the unit will display the current time on the seven-segment display (figure 3).
When either the brightness “up” or “down” command is received either from an IR remote or
from the manual inputs the display will change showing the numerical value of the brightness
level (figure 4). The brightness level ranges from 1 to 20. The intention is to emulate
controlling the brightness of the lamp like controlling the volume of a television. If no inputs are
detected for two seconds the unit will return to the idle state displaying the current time.
Figure 3. Display of the current time
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Figure 4. Display of brightness level “10”
The sleep function is also very much like the sleep function on a television. If the “sleep”
command is received either via the IR remote or manually, the display will show SPX, with X
corresponding the sleep duration (figures 5-8). If no input is detected for three seconds, the
displayed sleep duration will be accepted and the unit will return to the idle state. If the sleep
command is detected before the three seconds then the next sleep duration will be displayed. In
this way the user can select a sleep duration time by cycling though the sleep duration time
displays. The sleep duration displays will be SP15, SP30, SP45, SP1h, OFF and NULL. The
first five displays correspond to 15, 30, 45, minutes, 1 hour and sleep off respectively. The
NULL doesn’t do anything, meaning that if a sleep timer is already running and the sleep
command is received, there is a way to get out of the cycle without resetting the sleep timer.
Figures 5-10 shows all of these sleep displays.
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Figure 5. Display of “SP15” indicating sleep timer will be set to15 minutes
Figure 6. Display of “SP30” indicating sleep timer will be set to 30 minutes
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Figure 7. Display of “SP30” indicating sleep timer will be set to 45 minutes
Figure 8. Display of “SP1h” indicating sleep timer will be set to 1 hour
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Figure 9. Display of “OFF” indicating that the sleep timer will be turned off
Figure 10. Display of “cont” indicating that the current state of the sleep timer will not be effected.
Setting the clock is very much like setting the clock on a digital alarm, and can only be
done manually. The user must hold down the “set clock” button to set the time using the “up”
and “down” buttons. Holding down the “set clock” button will have no effect on the current
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display. The “up” button controls the hour and the “down” button controls the minutes. For
clarity these secondary commands will be labeled on the unit as well. A state diagram of the unit
is shown in figure 4.
Figure 4. State diagram
Idle
Sleep 15
Sleep 30
Sleep 45
Sleep 1 hour OFF Null
Light Intensity
Sleep
Sleep
Sleep
Sleep
Sleep Sleep
Sleep
3 seconds no input
3 seconds no input
3 seconds no input
3 seconds no input
3 seconds no input
3 seconds no input
2 seconds no input
Up or Down
Up or Down
All other inputs
All other inputsAll other inputsAll other inputs
All other inputs
All other inputs
Clock set
Hour or MinutesAll other inputs
Clock Set Depressed
Clock Set ReleasedReset
*Note- Inputs an be from the IR remote or from manual inputs
All other inputs
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Development Plan
The project will mainly be developed using resources of the EET lab, ET340 at Western
Washington University. The software will be written using the CodeWright code editing
software and tested using the Noral debugging system provided in the lab. Hardware
construction and testing will be done primarily in the lab. The primary equipment used will be a
digital multi-meter, dual trace oscilloscope, programmable power supply, and an IR remote.
Since this is a prototype it will first be constructed using a solderless breadboard to save time and
to also reduce the risk of shorting something out. The testing of the circuit using the AC main
will be done by encapsulating the circuitry to prevent accidental contact with the live wires, and
under the supervision of either professors Frank David Harris, Todd Morton, or Thomas Grady.
Once operation is confirmed if time permits, a printed circuit board may be pursued.
Construction of the housing will also be delayed until after the operation of the unit is confirmed,
but it will be designed to fit within the maximum specified parameters of the box described
above. Obtaining the necessary components isn’t expected to be a problem since they are fairly
common. The longest lead-time for part is the IR receiver, which is 2 weeks.
For demonstration I would need an IR remote controller and a lamp, both of which I already
own. I will also make a PowerPoint presentation explaining my project in more detail.
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The following is a weekly development schedule for the last weeks of Winter quarter and of
Spring quarter of 2007.
Week 9 (Winter) Refine Project DescriptionWeek 10 (Winter) Order PartsSpring Break Research/Work on HousingWeek 1 Assemble Hardware/Hardware DescriptionWeek 2 Test Hardware/Start IR demodulating moduleWeek 3 Test/Finish IR demodulating moduleWeek 4 Dimmer Software/TestWeek 5 Display ModuleWeek 6 Real time Clock ModuleWeek 7 Main programWeek 8 Put it all together/TestingWeek 9 Testing/Housing Construction (If have time)June 7, 2007 Demonstrations
Electrical Specifications
Power Source: 120VAC Main
Worst Case Power Dissipation (Unit): 268mA
Outlet Max Current (w/60W light bulb): 1.05A
Outlet Type: Three prong
Operating Temperature Range: 40°F-120°F
Time Accuracy: 4 seconds/6 months
Brightness Steps: 1-20
Sleep Time Durations: 15 minutes, 30 minutes, 45 minutes, 1hour
IR Protocol: RC5
IR Remote Commands: Volume Up/Down, Power, Sleep
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Preliminary Parts List
Part Name Part Number/Value
Source Lead Time
Power Dissipation
Quantity Cost($)
MCU MC9S12C32 Todd Morton
On Hand 35mA 1 11.28
IR Receiver TSOP1836 Electronic Goldmine
1-2 weeks 1.5mA 1 1.15
Resistor 470Ω EET On Hand 5mA 1 .15Resistor 470KΩ EET On Hand 50mA 4 .60Resistor 100Ω EET On Hand 10mA 1 .15Resistor 10KΩ EET On Hand 15mA 1 .15Capacitor 4.7uf Electronic
Goldmine1-2 weeks ~0mA 1 1.00
Electrolytic Capacitor
470uf/22V Electronic Goldmine
1-2 weeks ~0mA 1 1.00
Capacitor .1uf EET 1-2 weeks ~0mA 1 .50Capacitor 1uf/600V Tedss 1-2 weeks ~0mA 2 10.007 Segment LED Driver
MAX6954 Maxim 1-2 weeks 30mA 1 5.26
Electrical Chord
N/A On Hand On Hand N/A 2 6.99
Diode 1n4007 Electronic Goldmine
1-2 weeks 2.5mA 4 2.00
Zener Diode
5V1/.5W1N473
Cascade Surplus Electronics
1-2 weeks 1ma 1 .25
Triac BTA 16-6006BW
Electronic Goldmine
1-2 weeks 10mA 1 1.00
XTAL 32.7Mhz Digikey 1 week 15mA 1 2.54Real Time Clock Chip
DS1305-ND Digikey 2 weeks 15mA 1 5.06
Seven Segment Display
.8 inch single digit
All Electronics Corp
1 week 80mA 4 2.20
Bridge Rectifier
2A/30V Digikey 1 week 2.5mA 1 2.50
5V Voltage Regulator
LM7805 Digikey 2 weeks 1mA 1 2.04
Transformer 120/25.2V AC/2 Amp
Digikey 2 weeks N/A 1 10.75
Wall outlet Standard Lowes Immediate N/A 1 5.99Totals 268.5ma $87.41
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