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A PC-Controlled Burglar Alarm System This month, we complete the construction, describe the test procedure and give the “driving instructions” for the software. We also describe the optional keypad module which can be used to arm & disarm the system. Pt.2: By TRENT JACKSON H AVING COMPLETED construction of the alarm unit, it’s time for the test procedure. At this stage, microcontroller IC1 should be out of its socket and the SLA battery should be disconnected. It’s also a good idea to disconnect the display board from the main control board until the power supply has been checked out. Here’s the step-by-step test procedure: Step 1: apply 16VAC power to the main controller board (but leave SLA battery disconnected). Step 2: set your DMM to read DC volts and check the output from the 12V regulator (REG1). Anywhere from 11.5-12.5V is acceptable. Now, do the same for the 5V regulator (REG2) – its output should be very close to 5V. If either of these readings is drastically low, switch off immediately and check for shorts on the PC board and for polarised components that may be the wrong way around. Step 3: check the voltage across the battery leads (ie, between ZD1’s cathode and D7’s cathode). You should get a reading of 13.6-14V (this is the charging voltage). If this checks out, connect the bat30  Silicon Chip tery and repeat the last step. Depending on the amount of charge in the battery, you should get a reading in the range of 13-13.6V (a flat battery will give a lower reading). Step 4: check that +5V is present on both pins 11 & 32 of the microcontroller’s IC socket. If so, switch off, connect the display board, re-apply power and check that the mains power LED is lit (the other LEDs should all be off). Also, check for a +5V rail on the three righthand pins of the key socket connector on the display board. Step 5: disconnect the power supply and plug the PIC microcontroller (IC1) into its socket. Take care to ensure that pin 1 is at upper right – see Fig.5 in part 1. Step 6: this step checks the basic operation of the two PC boards. First, connect a sensor (PIR or reed switch) to the input of zone 1. As a default, the system assumes that N/O (normally open) sensor contacts will be used. When the sensor is triggered, you should see the status LED for zone 1 illuminate. This LED should then extinguish when the sensor is reset. Repeat this test for the remaining seven zones, checking that their allocated LEDs respond accordingly. Step 7: it’s now time to interface the system to your PC and test the various features. Connect it to the PC via an RS232 serial cable, then install and run the software. Refer to the large “Driving The Software” panel for information on the various software interfaces. Step 8: click on the “Comms” setup button and select the serial port that’s to be used. Now click on the button labelled “Test”. If you have selected the correct port number, you should see all the LEDs on the front of the unit counting up in BCD (binary coded decimal). You should also hear the internal siren briefly chirping in synchronisation with the LEDs. If this doesn’t occur, check that the port is operational and valid. Doublecheck to ensure the integrity of your serial port cable and that the RS232 IC is installed the right way around. Step 9: before proceeding to secure the system with passwords, check the door strike outputs. These are operated through the Arm/Disarm interface. Using your DMM, you should be able to measure 12V across their terminals when activated. Don’t set the duration time for any given strike longer than it really needs to be. They siliconchip.com.au Fig.8: the complete circuit details for the optional keypad module. It’s based on a PIC16F84A microcontroller (IC1) and a standard 3 x 4 matrix keypad. draw high current and the power supply is quite modest. Step 10: click on the arm button for zone 1. The internal siren should briefly chirp and the corresponding “armed” LED should light. Click on the disarm button and check that the LED extinguishes. Step 11: secure the system with passwords and configure the entry/exit delays, siren duration times and autorearming features (if needed). Step 12: this is the fun part – install the alarm into your premises and run the cables to all the sensors. The keypad The keypad is for those who don’t wish to use a computer to arm and disarm the main alarm system. That way, you only need a PC for the initial system set-up and to define parameters and passwords. A keypad is also useful if you want to use the system as a domestic house alarm and don’t need the versatility offered by the Windows-based softsiliconchip.com.au ware. Alternatively, you can build the keypad for emergency use only – ie, to arm and disarm the system in the event of a blackout or computer malfunction. In the latter case, the keypad also lets you do away with the “Hard-Wired Key”, which can be rather inconvenient to use. If the power fails, just plug the keypad in and you’re in business. Furthermore, the keypad can both arm and disarm the system, whereas the “Hard-wired Key” can only disarm the system Up to four passwords can be defined via the Windows software, as shown in one of the screen grabs. However, you don’t have to type in a password for all four – just leave them blank if you don’t require them. Note that to access this feature, you need to be logged in as either an Owner or Admin. These passwords are stored in the PIC microcontroller in the main alarm unit (ie, in EEPROM) and must be four digits in length (numerals only). The star (*) and hash (#) keys are used only to arm and disarm the system. To arm the system, just enter the 4-digit code and press *; to disarm it, enter the 4-digit code and press #. Easy! If the code is correct, a short melody is played. However, if the code is entered incorrectly, then a short series of chirps will be heard. It’s then just a matter of re-entering the correct code but you only get five attempts, after which the system locks you out for 30 minutes. By the way, this unit is quite universal and could easily be adapted to suit a host of other applications. It’s not just suitable for used with the PC-Controlled Alarm. Another PIC Inside the keypad module is – yes, you’ve guessed it – another a PIC microcontroller. This time, it’s a 16F84A and this is teamed with a standard numerical keypad and a handful of minor parts. A vital ingredient is the software March 2006  31 Driving The Software For The PC-Controlled Burglar Alarm T HE SOFTWARE for the PC-Controlled Burglar Alarm has been tested with Windows XP and Windows 98SE but should also work with Windows 95, Windows 98 and Windows 2000. It’s separated into seven main sections to make it easy to drive: (1) Access Control; (2) Log On/Off; (3) Comms Setup; (4) Zone Configuration; (5) System Logging; (6) Entry/Exit Delays and Arm/Disarm. The main GUI is shown immediately below. The software assumes no security until an owner password is created. If you have just loaded the software and want to test the unit before finalising access settings, you can just basically go straight to the Communications Setup window to begin testing. Select the Comm port that you wish to use, then cover your ears and click on the relevant Test button (see GUI below right). The internal siren should sound and all of the LEDs on the front panel should start counting up in binary. If this occurs, then there’s a good chance that your new alarm system is ready for installation. Before doing so, however, it would be a good idea to check that all the zones can be armed and disarmed. THIS IS THE MAIN GUI for the Windows-base software. It’s divided into seven sections (no confusing drop-down menus to explore), which makes it really easy to drive. Clicking on each of these sections brings up the various other configuration panels shown on these pages but first you have to define the various users and set-up access control as shown in the GUI at the bottom of this page. Once you have the system setup, you arm or disarm the system by simply logging on and clicking the Arm/Disarm section to bring up the GUI on the facing page. It’s then just a matter of clicking the Arm or Disarm button for each Zone, as appropriate – or you can arm or disarm all zones simultaneously. THE COMMUNICATIONS SETUP screen allows you to define the RS232 ports that you wish to use to communicate with the PC and the (optional) modem dialler. Make sure that you don’t include any spaces in the phone number string. The two Test buttons help you choose the correct serial ports on the PC and to diagnose faults – see text. PASSWORDS CAN BE alphanum­er­ic in which case you have to use a PC keyboard to log on. Alternatively, if the password has numerals only, you can enter it by clicking the numbers on the virtual keypad shown here. THE FIRST STEP IN SETTING UP THE ACCESS CONTROL for the system is to create an “Owner” user name & password. This is done by keying in a name and password, then selecting the “Owner” option and clicking the “Add” button. Doing that gives you control over the entire system. However, you cannot do much unless you log on. To do that, click the “Log ON” button at bottom right and key in the password that you just set up. If the password is valid you will be greeted with a MSG box that says “Hi”. You can create up to four Owners, eight Admins and 16 Users. Owners can create or delete other Owners, Admins and Users, while Admins can create and delete Users only. Users have defined access level privileges, most of which are selfexplanatory. 32  Silicon Chip siliconchip.com.au ABOVE: THIS IS WHAT THE “ARMING & DISARMING” GUI looks like. You need to have Owner or Admin access to modify these settings. Auto Rearm does exactly what it states – after a preset time, a zone that’s been disarmed automatically rearms itself. This could be useful for monitoring an entrance way, for example, and keeping a log of people who have entered (or left) a building. Note that you can give each zone a label value (eg, “Kitchen”, “Lounge Room”, etc). There are lots to choose from, so that you can easily identify zones. Clicking the “OK” button saves any new settings. The virtual red LEDs next to the Disarm buttons clearly indicate which sectors have been armed. When you arm or disarm a zone, you will hear the internal siren briefly chirp to indicate success. You can also arm/disarm all zones simultaneously. Finally, the Door Strikes buttons at the bottom allow Owners, Admins or Users with defined access to operate the door strikes. Five seconds should be more than ample time for the strike to be activated but you can adjust this value if you wish. THE CONFIGURATION GUI allows you to specify the sensors to be used for each zone – ie, either normally open (N/O) or normally closed (N/C). The status LEDs indicate the condition of each zone. When a zone is triggered, its corresponding LED lights up. This GUI also allows you to set up the keypad codes and shows the config­ uration for the “Hard Wired Key”. You simply select the BCD code and the number of inserts required and the accompanying diagram shows the wiring for the D9 connector. Make sure that the system is plugged into your PC’s serial port before clicking the “OK” button, so that the settings are saved to the PIC’s EEPROM. siliconchip.com.au THE ENTRY/EXIT DELAYS GUI lets you customise the delay settings for each zone (0-255s). As with other settings, these delay times are saved in the PIC, so that the system can be operated without a PC if necessary after set-up (although you do lose features). By default a tripped zone is automat­ i cally rearmed 30 seconds after the siren times out. You can set the maximum number of “rearms” to anywhere between 0 and 9, so that a zone will eventually be locked out after repeated triggerings (eg, to guard against a faulty sensor). Check the noise pollution laws for your state before implementing this feature. Set this value to 0 if you want each zone to be locked out immediately after it has been triggered. THE WIRING DIAGRAM in the Configuration GUI shows you how to wire the Hard Wired Key for a given BCD code and number of inserts. March 2006  33 The data logger records all activity from people logging onto the system, as well as which zones have been triggered and the alarm conditions. To gain access to this screen you must have Owner, Admin or set user level privileges. Each time the software loads, the data log loads as well. It’s then automatically saved at a specified interval. This arrangement means that you don’t have to worry about power failures or having to manually save the logs each time you power down the PC. However, you still have the freedom to manually load and save logs. Up to 2000 samples can be stored which should be more than enough. that’s programmed into the PIC. This software monitors the key presses and produces a serial data stream which is then fed to the PIC microcontroller inside the alarm unit. This in turn scans its passwords database and if it finds a match, allows access to the system. The keypad is perfectly standard – you just press the digits, hit the hash key and the PIC microcontroller spits the digits out serially at 2400 baud. Pressing the hash key inserts CHR$(66) at the start of the data string, while pressing the star key results in CHR$(88) being sent first. This instructs the alarm to either disarm or to arm, respectively. After the function BYTE, the 4-digit code follows in a plain ASCII format. A few minutes of experimenting will allow people with relatively modest PICAXE experience to interface it to their own projects. Automatic resetting Another feature of the keypad module includes automatic resetting if it’s at idle. This simply means that if you don’t press in each subsequent digit There are just a few wire links inside the “HardWired Key” and the software shows you how to wire it. Note that when using this key, you must allow at least a one second time frame between each insertion and withdrawal. If the time frame is too great, the system will lock out for a short period. 34  Silicon Chip in the code sequence within four seconds, the system resets and you have to start over again. This is done to ensure security – ie, it ensures that you have to key in your complete password every time you want to arm or disarm the system. A piezo transducer and a red LED provide audible and visual indication of keypad activity. Each time a digit is pressed, a “chirp” is produced by the transducer. Other sounds are also produced by transducer, depending on the status of the keypad (eg, to indicate correct or incorrect codes). In use, the unit plugs directly into the D9 female socket on the alarm to establish the communications link. In addition, a +5V rail to power the unit is also obtained from the D9 socket. You can plug the unit into the D9 socket (and unplug it) with power applied. However, don’t swap between the PC’s serial port and the keypad port while the Windows-based software is running, otherwise the alarm system may lock up. If it does, you’ll have to reset the alarm by removing all power to it (including the back-up battery). Note: you can “hot-swap” from the keypad to the PC and vice versa if the Windowsbased software is showing the main menu GUI only, or is not running. How it works Fig.8 shows the complete circuit details for the keypad module. As stated, it’s based on a PIC16F84A microcontroller (IC1) and a standard 3 x 4 matrix keypad. The keypad rows are monitored via ports RA3, RB3, RB2 & RB0, while the columns connect to ports RB1, RA2 & RA4. The latter three ports (ie, to the columns) are all set as outputs and are switched at a rate of about 100Hz “total cycle time” – ie, each port is toggled from high to low about 33 times a second. RA3, RB3, RB2 & RB0 (which monitor the rows) are all configured as inputs. These are all normally pulled high to +5V via 100kW resistors, to ensure they don’t “float”. In addition, a 2.2kW resistor is connected to RA4 due to the fact that this pin can sink but not source current. In operation, IC1 pulls each of the columns low in turn and checks for key presses on the rows. For example, if RA2 is low and digit 5 is pressed, the RB3 will be pulled low. IC1 decodes siliconchip.com.au Fig.9: follow this diagram and the photo above to build the keypad unit. The external connections from the PC board are all made via pin headers and connectors. these key presses and produces a digital data stream at its RA1 port. This information is then fed via the D9 connector to port RC3 of the PIC microcontroller inside the main alarm unit. If the password is correct, RA0 on IC1 is briefly toggled high for about 200ms, LED1 flashes and the piezo transducer plays a short “melody” to acknowledge that the correct code has been entered. Note that there are two very distinct “melodies” – one for a valid password and one for an invalid one. LED1 and the piezo transducer are switched on and off via Q1, which is in turn controlled by port RB5 on IC1 via a 4.7kW base resistor (this sets the nector on the display board, inside the main unit. This connects to pin 1 on the D9 socket (note: you will have to make this connection inside the main alarm unit). A 10mF electrolytic capacitor and a 100nF MKT capacitor provide a modest degree of filtering for the supply rail. Finally, IC1 is clocked at 4MHz, as set by crystal X1. The two associated base current to just under 1mA). Assuming that the beta gain of Q1 is 100 then the available collector current will be close to 100mA. When RB5 goes high, Q1 turns on and so LED1 and the transducer also turn on. A 330W resistor limits the current through the LED to about 10mA, while a 15W resistor limits the volume from the piezo transducer. Reset line & power Table 2: Capacitor Codes The MCLR pin of IC1 is pulled to the +5V supply rail by a 2.2kW resistor. This ensures that the microcontroller is reset when power is first applied. The +5V supply itself is derived from a +5V rail on the keysocket con- Value μF Code EIA Code IEC Code 100nF 0.1µF   104 100nF 22pF   NA    22   22p Table 1: Resistor Colour Codes o o o o o o siliconchip.com.au No.   4   1   2   1   1 Value 100kW 4.7kW 2.2kW 330W 15W 4-Band Code (1%) brown black yellow brown yellow violet red brown red red red brown orange orange brown brown brown green black brown 5-Band Code (1%) brown black black orange brown yellow violet black brown brown red red black brown brown orange orange black black brown brown green black gold brown March 2006  35 Par t s Lis t Keypad Advantages & Disadvantages 1 PC board, code 07203061, 104 x 38mm 1 IP65 ABS case, 115 x 65 x 40mm (Jaycar Cat. HB-6122) 1 front panel label (download from www.siliconchip.com.au) 1 4MHz crystal (X1) 1 3 x 4 matrix numerical keypad 1 piezo transducer (Jaycar Cat. AB-3440) 1 D9 male connector 2 D9 female connectors 2 D9 backshells 6 M3 x 10mm screws & nuts 4 M3 x 5mm screws 1 18-pin IC socket (for IC1) 1 150mm length rainbow cable 1 1-metre length 4-core cable 2 small cable ties, 100mm 1 4-way SIL locking pin header & connector, 2.54mm (CON1) 1 2-way SIL locking pin header & connector, 2.54mm (CON2) 1 10-way SIL locking pin header & connector, 2.54mm (CON3) The keypad module was developed mainly to make it easier to disarm the alarm system in the event of a mains or PC failure, as opposed to using the hard-wired key. Unlike the hard-wired key though, it can also be used to arm the system. That means that you can do away with the PC and just rely on the keypad if that’s more convenient. There are some drawbacks to relying solely on the keypad, though. Basically, you lose the nifty access control features that the PC software has to offer. Four codes can be defined for the keypad but they all provide full control over the system – the keypad either turns the whole system (ie, all zones) on or off. Note that the independent zone entry/exit delays and the siren duration time are stored in the main system, so you don’t lose these settings if you decide to rely on the use of the keypad after the initial set-up. There’s just one thing to watch out for here – if you disarm the system using a PC and then rearm it using the keypad, the auto rearm options will kick in (assuming they’re set). This is because the PC sends a command to the alarm for auto-rearming when you click on the disarm button. This command also includes the time duration before auto-rearm is applied (although this obviously only occurs if it’s enabled). This is something to watch out for if you decide to use both the keypad and the PC. Semiconductors 1 PIC16F84A microcontroller pro­grammed with keypad.hex (IC1) 1 BC548 NPN transistors (Q1) 1 5mm red LED (LED1) Capacitors 1 10mF 16V electrolytic 1 100nF MKT polyester (code 104) 2 22pF ceramic Resistors (0.25W, 1%) 4 100kW 1 330W 1 4.7kW 1 15W 2 2.2kW Where to buy parts PC boards for this project are available from RCS Radio, phone (02) 9738 0330. In addition, RCS Radio offers a programming service for the PIC chips used in both the keypad and the main alarm unit. EXT Siren + - INT Siren + - Door S A + - Door S B + - 22pF capacitors provide the correct loading on the crystal, to ensure reliable starting. Construction All the parts except for the D9 connector, transducer and LED are installed on a PC board coded 07203061. It measures just 104 x 38mm and fits into a standard IP65 plastic case from Jaycar. Fig.9 shows the parts layout on the PC board. It should only take you 10 minutes to assemble and you can install the parts in any order. Use a socket for microcontroller IC1 and take care to ensure that this IC and transistor Q1 are both oriented correctly. Similarly, make sure that the 10mF capacitor is installed correctly. Table 1 shows the resistor colour codes but it’s also a good idea to check them using a digital multimeter. Don’t forget the wire link that’s adjacent to the 4MHz crystal (X1). The Tamper Switch 1 Com N/C GND RX TX Alarm OUT < ZONE INPUT > 2 3 4 5 6 7 +12V 8 ~ ~ AC IN Alarm OUT Fig.10: these labels can be cutout and affixed to the main board in the alarm system – ie, adjacent to the external wiring connectors. 36  Silicon Chip crystal can go in either way around. Once the board assembly is complete, mount the keypad on the lid of the case – use the front panel label as a template to mark the cutout and the four mounting holes. The cutout can then be made by drilling a series of holes around the inside perimeter, knocking out the centre piece and filing the job to a smooth finish. That done, the kepad can be fastened to the lid using four M3 x 10mm screws and nuts. The PC board can then be mounted in position. It’s secured to the integral pillars in the case using for M3 x 5mm screws – see photo. Finally, complete the construction by wiring the D9 connector, piezo transducer, LED1 and the keypad to their respective connectors and plugging them into the on-board headers. Testing Before testing, you need to open up the main alarm unit and connect a link between pin 1 of the D9 connector and one of the +5V pins on the key socket connector. This is necessary so that a +5V rail is applied to pin 1 of the D9 connector on the keypad module. After that, it’s simply a matter of connecting the keypad module to the alarm unit, setting up the password(s) in the software (via the configuration GUI) and trying it out. That’s it – your new alarm system SC is ready for action. siliconchip.com.au