Serial Port IR Receiver With Girder3

Md. Ashiqur Rahman [email protected]

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Introduction Infrared remote signal receiver is a complex circuit usually embedded in a fabricated IC. Generally three types of receivers are used, those works under frequency of 36 KHz, 38 KHz and 40 KHz. 36 KHz receiver IC can sense and work with infrared signal of 36 KHz, 38 KHz receiver IC can sense and work with infrared signal of 38 KHz and 40 KHz receiver IC can sense and work with infrared signal of 40 KHz. Among those 38 KHz IC is widely used. To make an infrared signal sender work with the receiver, their signal range should be matched. This has done using Infrared remote signal receiver TSOP 1738 IC. The IC works in 38 KHz signal frequency. We have selected this IC as most of the remote controllers have been made to work on 38 KHz frequency. So, the IC can work with most of the infrared remote controller or infrared signal sender. The signal is received in the serial port of computer and the analog signal is then digitalized. Here the decoding of infrared signal has done using software decoder that decodes the received signal coming from the serial port and sends it to the appropriate software to work according to the decoded digital signal. In this project RC-5 decoding has been implemented. The software Girder version 3.2.9 is used to control various windows application according to the parsed digital signal. Girder3.2.9 is free software that is used to control various windows application by various external controlling devices. The objective is to design and implement an infrared remote control receiver that is capable to control Computer from a remote/distant place within the supported range provided by the IR. The circuit could control various computer programs.


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Receiver Circuit Operations 1 Introduction

The circuit gets power through serial port. Data sensed by the sensor circuit is transmitted to computer through serial port. An infrared sensor has been used to sense infrared signals. A led is connected to circuit that emits if any signal is received. This chapter has tried to present the theoretical analysis and development at every point. Here also given a stepwise and point-to-point idea about the project. 2 Description This chapter deals with the Hardware (circuit) implementation of the infrared remote receiver. The circuit contains two parts:

i) Implementing the receiver circuit. ii) Connecting with the serial port.

Circuit components

a) 1x TSOP1738 infrared sensor IC

b) 1x 1N4148 Diode

c) 1x 78L05 IC

d) 1x 4.7 µF 16V Capacitor

e) 1x LED 3V

f) 1x 3V Battery

g) 1x BC548 Transistor

h) 1x BC558 Transistor

i) 1x 220Ω Resistor

j) 1x 3.3KΩ Resistor

k) 2x 10KΩ Resistor

l) 2x 100KΩ Resistor

m) 1x Serial Port (9 Pin Female)


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Circuit Diagram

Figure 2.1: Complete Circuit Diagram


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3 Circuit operation From the circuit diagram in figure 2.1 The Source acts as source of power to run the whole circuit. 10V DC voltage can be found at this point coming from computer’s serial port. In the Read, the received signal can be found. 1N4148 Diode has been used to make the current flow omni directional and towards the receiver sensor. 3.3 KΩ Pull-up resistor has been used to normalize the received signal. It is also used to ensure that the signal to be sent is within the range of the corresponding decoder. Increasing in resistance up to 10KΩ will increase the sensitivity of the circuit. Its one node is connected with the negative terminal of the diode and another node is connected with the Out (Pin 3) of the sensor (Figure 2.1). IC 78L05 is a regulator IC. It is used to regulate the received voltage from Source point of serial port. This IC regulates the received voltage and scales down to 5V. The output from this IC is connected with the Vcc of TSOP1738 IC and the positive (+ve) terminal of the capacitor. The 4.7 µF 16V Capacitor has been used to get smooth DC supply as well as to get instant current supply needed to do a single operation by the sensor. TSOP1738 is the infrared signal detection sensor that can sense infrared signal of 38 KHz and sends different electric signals for different frequency IR signals through Out Pin (Pin 3). Next part of the circuit has been used to emit a LED if any signal is received. In this part two wires coming from the Vcc and Out pin of the sensor IC connected directly with two 10 KΩ resistors respectively and then Transistor BC548 and BC558 according to the Figure 2.1. When a signal is sensed in TSOP 1738 IC it sends a current through the out pin (Pin 3). The current comes to the Base of the transistor BC558 and enables the transistor. So, current passes from the 3V battery as BC548 transistor is always in saturation state and the LED fleshes. The BC 548 transistor has been use to avoid direct connection between LED and the diode’s negative (–ve) terminal, otherwise there is a possibility to burn out the LED.


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4 Serial Port Configuration The Source (Figure 2.1) has been connected to both RTS (Pin 7) and CTS (Pin 8). Read has been Connected to DSR (Pin 6) and the Ground has been connected to both SG (Pin 5) and RI (Pin 9). All other pins remained unused.

Figure 2.2: Serial port connection

5 Summary As a summery of the whole circuit it can be said that, the circuit has an infrared sensor that takes 5V DC power supply for biasing. The biasing power is supplied through the serial port. The power supplied is 10V. The power has been converted to 5V using the Voltage regulator and then supplied to the sensor. The sensor transmits data sensed through its pin 3 that goes to serial port and software captures the data. This is the basic principle of the circuit. The whole operation has been described elaborately in this chapter.


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Software to Control Computer 1 Introduction To control windows application through the receiver, a software is needed named Girder. The software should be installed first and should be configured properly so that it can detect the device and work properly with the device. There are some configurations to help this software to run properly. This chapter has tried to present the installation, all kinds of configuration and operation of the software. This chapter will also show the way to control various windows applications. 2 Girder The signal sensed from the infrared receiver circuit is usually converted from analog to digital using a software decoder. The decoder sends the digital signal to software that will do the controlling operation of the computer programs. The software used in this project is Girder version 3.2.9. This software is compatible with Windows 98, windows 2000 and Windows XP. This software can be used to send control signal to various windows applications. It can also send all Keyboard and Mouse signal to computer that makes possible to control mouse cursor or sending the keyboard key signal from the infrared remote controller. This application works with different plugins. Those plugins makes the software possible to work with various external devices. Igor plugin is the plugin that make this software work with the infrared remote control receiver. First Girder 3.2.9 should be installed. After installation of the Girder, it can be started from the location, Start > Programs > Girder 3.2 > Girder 3.2. Igorplug.dll file should be copied to “C:\Program Files\girder32\plugins” directory to work with infrared remote receiver device. 3 User interface of Girder In Girder’s user interface, there are four menus, File menu, Edit menu, Command menu and Help menu. The circular bulb in status bar of girder indicates the activity of the software. If it is Blue then the hardware device associated with it is inactive. If dark green that indicates the hardware device associated with it is active but not sending signal. This turns out to light green if the hardware sends signal. An icon appears on windows system tray when girder is loaded in memory. This icon states the status of the software. When the icon has a cross (X) sign over it that means the hardware device associated with girder is inactive. If normal then the hardware device associated with it is active but not sending signal. This flashes if the hardware sends signal.


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Figure 3.1: Girder user interface File Menu

Figure 3.2: File Menu

“New” will start a new file that can be used to store different signal information and their corresponding operation to be performed. By clicking “Open” a box like Figure 3.3 will appear and a previously saved file can be selected exploring to the saved path and opened by clicking the open button.


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Figure 3.3: Open Dialog Box “Save” command lets the user to save all changes done by the user into a single file. If the file has been previously saved entitled a name then this command only updates the file till the last change. If a new file has been opened and not saved yet, then it opens a prompt window like Figure 3.4. Typing a name in “File Name” field and pressing “Save” button saves the file to that name.

Figure 3.4: Save As dialog box

“Save As” is same as “Save” except it gives the user facility to save a file using different name.


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“Lock” command opens a prompt (Figure 3.5). Typing a password and clicking OK locks the software from unauthorized access. After Locking, password is needed to make any kind of change to the software.

Figure 3.5: Locking the Software “Import Group” command is used to import commands from different file to the current file. “Export Group” command is used to export or save a group of commands to another file from the entire file.

Figure 3.6: Settings Dialog Box “Settings…” command is used to change various settings of the software. Clicking “Settings…” open a dialog box like Figure 3.6. There are four tabs in “Settings” dialog box. To change general settings “General” tab should be clicked and a dialog box appears (Figure 3.6).

There is a text box and “Browse” button right below the “Auto Load” check box. By selecting a girder command file(*.GML) by clicking “Browse” button


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along with “Auto Load” check box checked, loads the girder along with the selected file opened.

Checking the “Load girder on windows startup” loads girder wile starting windows.

Checking the “Don’t send the IR commands when Girder is the Foreground window” deactivate executing command when working with girder or when girder main window is open or in foreground.

“Hide on Startup” hides the main windows if girder starts on windows startup.

Figure 3.7: User interface setting

In “user interface” setting the language of the graphical user interface can be changed by clicking the “Language” drop down menu.

By clicking “Dotmatrix font” and choosing a font by clicking the browse button and selecting a font file changes the font of on screen display.

“Tray icon settings” under “User interface” has three tabs. Selecting “flash tray icon on every event” flashes the tray icon in every signal received from the hardware.

“Flash tray icon on every command” flashes the tray icon in every command executed rather than every signal received from the hardware.

“Never flash tray icon” deactivates flashing of tray icon.


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Figure 3.8: Plugins Setting

Clicking to “Plugins” tab in “Settings” appears window like Figure 3.8. This allows user to select appropriate plugin for the hardware.

“Auto Enable Input Device” check box automatically enables input device while starting girder.

Here “Igor SFH-56 device” checkbox should be checked on to work with serial infrared remote control receiver. After checking on the checkbox “Apply” button should be clicked to apply setting.

After selecting Igor plugin and clicking “Settings” button, a window appears like Figure 3.9.

Figure 3.9: Igor Plugin Setting

Port to which device is connected can be selected here by clicking “COM port” dropdown menu.


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Through “Input signal” dropdown menu the input signal’s pin can be selected. Default is DSR.

The ‘Advanced” button enables advanced device configuration (Figure 3.10)

Figure 3.10: Advanced Igor Plugin settings

Figure 3.11: On Screen Display (OSD) settings

To change OSD (On Screen Display) setting “OSD settings” tab should be clicked and the figure like Figure 3.11 appears. The width and height of the text to be displayed can be changed by putting values in “Width in pixels” and “Height in pixels” text box.

Value in “Left” and “Bottom” text box sets the position of the OSD text.


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Clicking on “Select font” button, a window appears (Figure 3.12). Where font type, size, color can be changed. After changing ok should be clicked to save changes.

Figure 3.12: OSD font selection window

Figure 3.13: Color Selection Window

“Select Background color” button (Figure 3.11) allows selecting any color for the background of the OSD. When the button is clicked, a window like Figure 3.13 appears that allows selecting a color. After selecting color, OK should be clicked. When changing settings finished, OK should be clicked to close “Settings” window and to save the changes done. “Disable input Device” command (Figure 3.2) is used to enable or disable input device connected with girder.


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“Close window” command (Figure 3.2) is used to close the active window of Girder and minimize it to system tray. “Exit Girder” is used to exit the software. Edit Menu

Figure 3.14: Edit Menu Using “Copy” command a single girder command or a group of commands can be copied. “Paste” pastes the copied command or a group to a desired place within girder. “Delete” can be used to delete a girder command or a group consists of multiple commands. “Rename” can be used to rename a girder command or a group consists of multiple commands. “Duplicate” can be used to duplicate a single girder command or a group of commands in the same file. “Add Command” is used to add a girder command (Figure 3.15). A Girder command holds the decoded digital data of the hardware associated with Girder and corresponding action should be taken. “Add MultiGroup” adds a Multi Group (Figure 3.16). A MultiGroup can hold more than one command group under it. It is usually used if number of groups is high enough to manage.


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“Add Group” adds a group (Figure 3.17) that can hold multiple commands. Every command must be under a group. “Add Toplevel Group” adds Top level group (Figure 3.18) where everything takes place under it. “Add Eventstring” adds an Eventstring (Figure 3.19) that contains the decoded digital code coming from the hardware. An Event String must be under a command.

Fig3.15: Command Figure 3.16: Multigroup

Figure 3.17: Group Figure 3.18: TopLevel Group


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Figure 3.19: Event string Command Menu

Figure 3.20: Command Menu “Test Command” executes a selected command to test whether the command is executing properly or not. “Set Group Target” can set a group of commands to target a specific application and all the commands under that group can control different threads of that application. “Clear Links” clears the link between a command and the associated application. Help Menu

Figure 3.21: Help Menu


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“Online Help” on Help menu opens a web page from internet to helps the user. “Discussion Board” opens an online discussion board. “About” opens a window that shows the full details about the software. Clicking on “Learn event” button in Girder’s Main window (Figure 3.1) takes Girder to learn state. If any decoded input signal is detected in learn state, that signal is saved for a command in a event string. Value in “Anti repeat wait time [ms]” text box prevents sending same repeated command within the time limit in millisecond. “Comment” text box has no function except user can add comment to any command. At the lower right side of the main window (Figure 3.1) has list of programs that can be controlled using Girder and the commands are arranged in different groups under different 4 Configuring software The configuration and working procedure involves three parts, Learning an event

Associating a program operation with a command

Executing a command

Learning an event To make Girder work, the software have to be learned about different signals coming from the infrared remote control. To do so, at first the Igor Plugin has to be selected and the input device has to be enabled assuming that the input device is connected to the right port of the computer. Secondly, a girder command should be added by clicking Edit > Add command. The main window will look like Figure 3.18


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Figure 3.22: Girder Main Window after adding command Thirdly, by selecting the command leveled “New”, Edit > Add Eventstring should be clicked to add an eventstring. Then click the Eventstring leveled “Eventstring” and then click “Learn event” button. Then, the main window will look like Figure 3.23.

Figure 3.23: Learning Event Pressing a button of infrared remote control directing toward the receiver, the decoded or digitalized code of the corresponding button appears and the main window looks like Figure 3.24. File >Save should be clicked to save the changes.


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Now, the corresponding button has been learned and associated with that command.

Figure 3.24: After learning event Associating a program operation with a command After finishing learning event, a program should be associated with the command. The program will execute by pressing the button in infrared remote control that belongs to the Eventstring. To associate a program operation, first the command should be selected then from lower right side of main window appropriate tab should be selected and under that tab a dropdown menu could be found, from that dropdown menu a program operation should be selected (Figure 3.25). Then “Apply” button should be clicked and the file should be saved.


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Figure 3.25: Associating a program operation

Figure 3.26: Capturing a thread of an application To grab a command of an external windows application, for example, to associate “pause” operation of “windows media player”, first open “windows media player” and play a song using it. Then, click to “command” tab from the lower right part of main window of Girder. Then click on target. A window will appear like figure 3.22. Click on “Start capture button of that window. Then each operation performed in “Windows” will be captured by this tool. Then click to “Pause” button of “Windows media player” and click to “stop capture” button. Select the appropriate command from the list (Figure 3.27) and click to “Apply” and “OK”


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button to close the window then save the file. The lower right part of the main window will look like Figure 3.28.

Figure 3.27: Selecting a thread or a command

Figure 3.28: The main window after capture Executing a command To execute a command, simply click the button that has been used to create the Eventstring, The associated application with that command will execute. 5 Summary This chapter contains the full details of the software that works with the infrared remote signal receiver. The working procedure involves, firstly adding a command and then learn various buttons in the IR remote using the learn command then associate operations to the corresponding command. This is the summery of the whole operation. The operation has been described elaborately in this chapter.


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Circuit components 1 Introduction In the main circuit there are various components like TSOP 1738 IC, Resistor, capacitor, diode, transistor, and Voltage Regulator has been used. So, this chapter describes elaborately about the TSOP 1738 IC and Voltage Regulator. This chapter will also discuss shortly about the Resistor, capacitor, diode and transistor. 2 TSOP 1738 IC The TSOP1738 are miniaturized receivers for infrared remote control systems. PIN diode and preamplifier are assembled on lead frame, the epoxy package is designed as IR filter. The demodulated output signal can directly be decoded by a microprocessor. TSOP1738 is the standard IR remote control receiver series, supporting all major transmission codes.

Figure 7.1: TSOP 1738 IC

Features: Photo detector and preamplifier in one package Internal filter for PCM frequency Improved shielding against electrical field disturbance TTL and CMOS compatibility Output active low Low power consumption High immunity against ambient light


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Continuous data transmission possible (up to 2400 bps) Suitable burst length .10 cycles/burst Internal Block Diagram

Figure 7.2: Internal block diagram of TSOP 1738 IC Suitable Data Format The circuit of the TSOP1738 is designed in that way that unexpected output pulses due to noise or disturbance signals are avoided. A bandpass filter, an integrator stage and an automatic gain control are used to suppress such disturbances. The distinguishing mark between data signal and disturbance signal are carrier frequency, burst length and duty cycle. The data signal should fulfill the following condition, Carrier frequency should be close to center frequency of the bandpass (e.g. 38kHz). Burst length should be 10 cycles/burst or longer. After each burst which is between 10 cycles and 70 cycles a gap time of at least 14 cycles is necessary. For each burst which is longer than 1.8ms a corresponding gap time is necessary at some time in the data stream. This gap time should have at least same length as the burst. Up to 1400 short bursts per second can be received continuously. When a disturbance signal is applied to the TSOP1738 it can still receive the data signal. However the sensitivity is reduced to that level that no unexpected pulses will occur.


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Some examples for suitable data format are, RC5 Code, RC6 Code, NEC Code, Toshiba Micom format, Sharp Code, R–2000 Code, and Sony Format (SIRCS). In this project RC-5 code has been used. 3 Voltage Regulator Voltage regulator equipment is used in a variety of industries to regulate the flow of materials. There are air regulators, beer regulators, and even feedback regulators for electronic circuits. All voltage regulators operate by comparing the actual output voltage to some internal fixed reference voltage. Any difference is amplified and used to control the regulation element. This forms a negative feedback, servo control loop. If the output voltage is too low, the regulation element is commanded to produce a higher voltage whereas if the output voltage is too high, the regulation element is told to produce a lower voltage. This type of circuit is different than that of an AC/DC voltage stabilizer. There are also switching regulators available in the electronics field, including linear and SCR regulators.

Figure 7.3: Voltage Regulator 78L05 In automatic control, a regulator is a device which has the function of maintaining a designated characteristic. For example, a voltage regulator maintains a constant voltage when the input is variable. Automatic control is the research area and theoretical base for mechanization and automation, employing methods from mathematics and engineering. A central concept is that of the system which is to be controlled, such as a rudder, propeller or an entire ballistic missile. The systems studied within automatic control are mostly linear systems. Automatic control systems are composed of three components: sensor which measure some physical state such as temperature or liquid level, responder which may be simple electrical or mechanical systems or complex special purpose digital controllers or general purpose computers and actuator, which affect a response to the sensor under the command of the responder, for example, by controlling a gas flow to a burner in a heating system or electricity to a motor in a refrigerator or


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pump. A regulator such as a thermostat is a typical example of a device studied in automatic control. 4 Diode A diode is any device possessing two (and only two) electrodes. Most diodes have 2 terminals, and most are used for their unidirectional current property, but neither of these applies to all diodes. Most modern diodes are based on semiconductor p-n junctions. In a p-n diode, conventional current can flow from the p-type side (the anode) to the n-type side (the cathode), but cannot flow in the opposite direction. Another type of semiconductor diode, the Schottky diode, is formed from the contact between a metal and a semiconductor rather than by a p-n junction. In this Experiment normal P-N junction 1N4148 (Silicon signal) diode and LED has been used.

Figure 7.4: Symbol of diode

Normal (p-n) diodes This type of diode operates as described above, usually made of doped silicon or, more rarely, germanium. Before the development of modern silicon power rectifier diodes, cuprous oxide and later selenium was used; its low efficiency gave it a much higher forward voltage drop (typically 1.4–1.7 V per “cell”, with multiple cells stacked to increase the peak inverse voltage rating in high voltage rectifiers), and required a large heat sink (often an extension of the diode’s metal substrate), much larger than a silicon diode of the same current ratings would require. The vast majority of all diodes are the p-n diodes found in CMOS integrated circuits, which include 2 diodes per pin and many other internal diodes. Light-emitting diodes (LEDs) In a diode formed from a direct band-gap semiconductor, such as gallium arsenide, carriers that cross the junction emit photons when they recombine with the majority carrier on the other side. Depending on the material, wavelengths (or colors) from the infrared to the near ultraviolet may be produced. The forward potential of these diodes depends on the wavelength of the emitted photons: 1.2 V corresponds to red, 2.4 to violet. The first LEDs were red and yellow, and higher-frequency diodes have been developed over time. All LEDs are monochromatic; “white” LEDs are actually combinations of three LEDs of a different color, or a blue LED with a yellow scintillator coating. LEDs can also be used as low-

+ -


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efficiency photodiodes in signal applications. An LED may be paired with a photodiode or phototransistor in the same package, to form an opto-isolator. 5 Transistor A transistor is a semiconductor device, commonly used as an amplifier or an electrically controlled switch. The transistor is the fundamental building block of the circuitry in computers, cellular phones, and all other modern electronic devices. Because of its fast response and accuracy, the transistor is used in a wide variety of digital and analog functions, including amplification, switching, voltage regulation, signal modulation, and oscillators. Transistors may be packaged individually or as part of an integrated circuit, some with over a billion transistors in a very small area. The transistor's low cost, flexibility and reliability have made it a universal device for non-mechanical tasks, such as digital computing. Transistorized circuits have replaced electromechanical devices for the control of appliances and machinery as well. It is often easier and cheaper to use a standard microcontroller and write a computer program to carry out a control function than to design an equivalent mechanical control function. In this project the BC 548 and BC 558 Transistor has been used. BC548 is a BJT NPN transistor and BC 558 is a BJT PNP transistor. Bipolar junction transistor

Figure 7.5: Symbol of BJT PNP and NPN transistor

The bipolar junction transistor (BJT) was the first type of transistor to be mass-produced. Bipolar transistors are so named because they conduct by using both majority and minority carriers. The three terminals of the BJT are named emitter, base and collector. Two p-n junctions exist inside a BJT: the base/emitter junction and base/collector junction. The [BJT] is useful in amplifiers because the currents


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at the emitter and collector are controllable by the relatively small base current. In an NPN transistor operating in the active region, the emitter-base junction is forward biased, and electrons are injected into the base region. Because the base is narrow, most of these electrons will diffuse into the reverse-biased base-collector junction and be swept into the collector; perhaps one-hundredth of the electrons will recombine in the base, which is the dominant mechanism in the base current. By controlling the number of electrons that can leave the base, the number of electrons entering the collector can be controlled. BC548 Pin layout Here, C means Collector B means Base E means Emitter BC558 Pin layout

6 Capacitor

A capacitor is a passive electronic component that stores energy in the form of an electrostatic field. In its simplest form, a capacitor consists of two conducting plates separated by an insulating material called the dielectric. The capacitance is directly proportional to the surface areas of the plates, and is inversely proportional to the separation between the plates. Capacitance also depends on the dielectric constant of the substance separating the plates. The standard unit of capacitance is the farad, abbreviated F. This is a large unit; more common units are the microfarad, abbreviated µF (1 µ F = 106 F) and the Pico farad, abbreviated PF (1 PF = 1012 F).

Figure 7.8: Symbol of a capacitor

C B E Figure 7.7: BC 558

C B E Figure 7.6: BC 558


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7 Resistor Most of the resistance in circuits is found in components that do specific work, such as bulbs or heating elements and in devices called resistors. Resistors are devices that provide precise amounts of opposition or resistance to current flow. Resistance value is designated in units called the ”Ohm”. A 1000 Ohm resistor is typically known as 1 K Ohm (Kilo Ohm), and 1000 K Ohms is written as 1M Ohm(Mega Ohm). Figure. 4.1 shows the symbol of a resistor.

Figure 7.9: Resistor Resistor rating color code Composition resistors are color coded to indicate resistance values or ratings. The color code consists of varies color bands that indicate the resistance values of resistors in ohms as well as tolerance ratings. Composition resistors generally have four-color bands. The color code read as follows, first look up the number values of the first two bands on the table and combined the two numbers. Multiply this two-digit number by value of the third band, the multiplier band. The resulting number is resistance value of resistors in ohms. The fourth band is the tolerance band. If the fourth band is gold, the resistors are guaranteed to be within five percent of the rated value. If the fourth band is silver, it is guarantee to be within ten percent. If there is no fourth band, their resistors are guaranteed to be within 20% of the rated value. 8 Summery In this chapter, every part of the project's circuit has been described. The components which are used in this proposal are shown in this chapter. This chapter also gives the total description of each and every component of the circuit.


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Conclusion It should be added that, if TSOP 1738 IC is not available in local market then almost any IR sensor IC exactly look like this IC would work. Just tell them that if any Television IR sensor is available that looks like that picture (Showing the picture of the TSOP1738 IC).

Documents

Serial Port IR Receiver With Girder3