Your SlideShare is downloading. ×
0
Akg 120310
Akg 120310
Akg 120310
Akg 120310
Akg 120310
Akg 120310
Akg 120310
Akg 120310
Akg 120310
Akg 120310
Akg 120310
Akg 120310
Akg 120310
Akg 120310
Akg 120310
Akg 120310
Akg 120310
Akg 120310
Akg 120310
Akg 120310
Akg 120310
Akg 120310
Akg 120310
Akg 120310
Akg 120310
Akg 120310
Upcoming SlideShare
Loading in...5
×

Thanks for flagging this SlideShare!

Oops! An error has occurred.

×
Saving this for later? Get the SlideShare app to save on your phone or tablet. Read anywhere, anytime – even offline.
Text the download link to your phone
Standard text messaging rates apply

Akg 120310

594

Published on

Used for presentation at AKG College of Engineering on March 12,2010.

Used for presentation at AKG College of Engineering on March 12,2010.

Published in: Education, Business, Technology
0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total Views
594
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
3
Comments
0
Likes
0
Embeds 0
No embeds

Report content
Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
No notes for slide

Transcript

  • 1. GVC Systems Pvt Ltd Electronics - Embedded - Entreprenurship
  • 2. Agenda About me About Embedded & Electronics About You Why I am here Inviting you to work with us
  • 3. Me - Professional Vinay Chaddha. Electronics Hobbyist. Author. Innovator. Passionate about learning and sharing. Filed 3 patents, Shared five successful commercial projects. Many copy rights. Developed over 200 comemrcially successful projects.
  • 4. CONSTRUCTION CONSTRUCTION Remote-controlled centre values of treble, balance and bass. Volume will be set at 50 per cent of the maximum value and the relay Audio Processor Using will be off. Loudness and mute will also remain in the off mode. A remote hand- set can be used to change the settings as desired. Caller-ID Unit Using transmit the telephone number of call- Microcontroller Audio controller. TDA7315 is a ing party just before the first ring while single-chip I2C bus-compatible audio in systems used in USA and China, the controller which is used to control all data relating to the calling number is functions of the audio amplifier. Stereo Micro-controller sent between first and the second rings. audio input from the preamplifier is fed The number of calling party in India is OO to the IC input. A microcontroller can SAG transmitted by MTNL/DoT exchanges VINAY CHADDHA G.S. in DTMF codes. PARTS LIST ILLO N Two documents containing stan- Semiconductors: M . DH A.P.S dards and specifications issued by DoT’s IC1 - TDA7315 digitally controlled VINAY CHADDHA ost hi-fi audio CD systems and 3. audio processor Telecommunications Engineering Cen- nowadays are available with IC2 - MC68HC705KJ1CP Motorola tre (TEC) in the form of ‘Generic re- T remote control. However, no microcontroller (GVC-AMP- he facility of knowing your tended to the normal telephone users quirements’ and ‘Interface require- such circuit is available for adding to Description 257) caller’s telephone number before also in Delhi, Mumbai and some other ments’ for ‘Subscriber service unit for Memory. 24C02 is an I2C bus compat- IC3 - 24C02 I2C serial EEPROM the AF power amplifiers made as hobby IC4 - 7805 fixed regulator +5V answering the call, which has cities of India through MTNL and DoT calling line identification presentation ible 2k-bit EEPROM, organised as 256 projects. The design of such an add-on IC5 - 7809 fixed regulator +9V been available to cellular phone users since 1st January. (SSU for CLIP)’ are available from TEC, x 8 bits. It can retain data for a period circuit along with remote control is pre- IC6 - µPD6121 infrared remote only in India so far, has now been ex- MTNL/DoT telephone exchanges Khursheed Lal Bhawan, Janpath, of more than ten years, including the control sented here. It can be used by hobby- T1,T2,T3 - BC547 npn transistor ists as an attachment to their audio current settings of volume, treble, bal- T4 - 2SC2001 npn transistor power amplifiers. ance, bass, as well as the on/off status D0-D7 - Red LED This design is based on audio con- of the main amplifier unit or the relay D8, D10-D11 - 1N4007 rectifier diode troller TDA7315 from SGS-THOMSON status. The various audio parameters D9 - 8.2V,0.5W zener can be stored in just six bytes. D12 - IR LED and Motorola microcontroller MC68HC705KJ1. The microcontroller, Mains power failure is quite com- Resistors (all 1/4W, ± 5% metal/carbon film, unless stated otherwise) after programming with the specific mon in India. This does not allow the R1,R2,R15,R16- 10-kilo-ohm software code for the current applica- last settings of volume, tone and bal- R3,R4,R14 - 1-kilo-ohm tion, has been renamed GVC-AUD- ance to remain intact. To overcome this R0,R5-R9, 257. Other construction projects by the microcontroller unit (MCU) must R12,R13 - 330-ohm the author using the same series of store all audio settings of the user in R10,R11 - 5.6-kilo-ohm memory (EEPROM). The memory en- R17 - 2-ohm, 0.5W microcontrollers, which can be referred R18,R19 - 200-kilo-ohm to for additional details, have been pub- sures that even after a power trip, the Capacitors: lished in EFY in Jun. ’97 (Set-Top Con- MCU will read the latest saved settings C1 - 10µF, 16V electrolytic verter) and Apr. ’99 (Caller ID). In ad- from the EEPROM. C2-C4,C7, dition to audio controller and Using two lines, SCL (serial clock) C19,C20 - 0.1µF ceramic disc microcontroller the circuit comprises and SDA (serial data), the microcon- C15,C16,C9, the following standard parts that are troller can read and write six bytes for C10,C11,C13 - 0.1µF polyester C5,C6 - 33pF ceramic disc used in any normal system: all the audio parameters. For more de- C8 - 22µF, 25V electrolytic 1. Power supply tails on I2C bus and memory interfac- C12,C14 - 2.7nF polyster 2. LED indicator panel to indicate ing, please refer to Caller ID construc- C17,C18 - 2.2µF, 16V electrolytic status/keys pressed tion project in Apr. ’99 issue of EFY. C21,C22 - 220pF ceramic disc At power ‘on,’ the last-saved audio C23 - 10µF, 50V electrolytic 3. Relay to switch on/off the supply to the power amplifier or the main unit settings are read by the MCU. In case Miscellaneous: memory IC cannot be read by the RL1 - 12V, 150 ohm, SPST relay The following parts are used in re- OEN Pt. No. 57DP-12-1C6 mote systems for VCR, TV, etc: microcontroller, volume LED will blink XTAL - 4MHz quartz crystal 1. Memory (24C02). three times to indicate the problem. The Y - 455kHz, ceramic resonator 2. Remote handset with 12 keys possible reasons could be either a bad - Battery 1.5V, pencil cell 3. IR receiver for remote operation memory IC, or a discontinuity/shorting - IR sensor module - Remote control handset, Functionality of these parts is ex- of its tracks, or improper insertion of complete with keyboard plained below with reference to Figs 1 the IC in its socket. - Connectors for audio input- The author is the proprietor of GVC Systems, Under the circumstances, the unit output and power supply will still work, but it will not remem- - 12V DC, 250mA battery Noida. He can be approached through e-mail eliminator at gvc@vsnl.com ber the last settings and will select the 52 ELECTRONICS FOR YOU SEPTEMBER '99 Fig. 1: Complete circuit diagram of caller-ID unit CC O NTS T RTU O N I O N ONS RUC I CT 44 ELECTRONICS FOR YOU APRIL '99 MICROCONTROLLER-BASED CMYK CONSTRUCTION MAR IL KU ACCESS CONTROL SYSTEM SUN BEVERAGE VENDING VINAY CHADDHA* the password data for over ten years. PARTS LIST MACHINE CONTROLLER The user can modify the password as S EO SANI TH Semiconductors: ecurity is a prime concern in our day- well as relay-activation time duration for IC1(U1) - MC68HC705KJ1 to-day life. Everyone wants to be as door entry. This version of software microcontroller much secure as possible. An access- enables use of the unit even without the IC2 (U2) - ST24C02 I2C EEPROM control system forms a vital link in a secu- I2C EEPROM. (However, without EEPROM, IC3 (MN1) - MN1280 reset stabiliser VINAY CHADDHA rants and even in companies. Press a allow compact size, higher reliability, rity chain. The microprocessor-based digi- the password and relay-activation time IC4 (Reg1) - 7805 +5V regulator switch and the machine delivers a hot lower cost and multiple functionalities. T1, T2 - BC547 npn transistor B tal lock presented here is an access- duration will be reset to default values everage vending machines are cup of your favourite drink. This tea/coffee/soup vending ma- (Q1, Q2) control system that allows only authorised on interruption of the power supply.) D1, D2 - 1N4007 rectifier diode commonplace at railway sta- This looks quite a simple operation chine controller uses Freescale’s latest persons to access a restricted area. LED1 - Red LED tions, airports, fast-food restau- but has a very complex logic behind MC908JL16 microcontroller chip. The it: It involves use of controller is programmable and user- Hardware details Resistors (all ¼-watt, ± 5% carbon, unless twelve precision timers friendly. You can set the quantity of System overview Fig. 2 shows the access control circuit. Its stated otherwise): R1-R6 - 10-kilo-ohm and four counters apart the beverages through a button switch The block diagram of the access-control main components are a microcontroller, R7-R9 - 1-kilo-ohm from physical devices like provided on the front panel of the con- system is shown in Fig. 1. The system I2C memory, power supply, keypad, relay, Capacitors: display, solenoid and mo- troller as per your requirements. Thus, comprises a small electronic unit with a and buzzer. C1, C2 - 33pF ceramic disk tor to deliver water and cups of any size can be filled at any numeric keypad, which is fixed outside the M ic r ocon t r olle r . The 16-pin C3, C4, premixed tea/coffee/soup time. entry door to control a solenoid-operated MC68HC705KJ1 microcontroller from C6, C7 - 0.1µF ceramic disk powder in exact quantity lock. When an authorised person enters a Motorola has the following features: C5 - 10µF, 10V electrolytic for better taste and in ex- The hardware predetermined number (password) via the • Eleven bidirectional input/output Miscellaneous: act sequence. Fig. 1 shows the block diagram of the keypad, the relay operates for a limited time (I/O) pins Xtal (Y1) - 4MHz quartz crystal to unlatch the solenoid-operated lock so the • 1240 bytes of OTPROM program PZ1 (BZ1) - Ceramic piezo buzzer This has become pos- vending machine controller. It com- door can be pushed/pulled open. At the end memory Con1 - Power-supply connector sible because of the use of prises the following sections: power The prototype of beverage vending machine controller of preset delay, the relay de-energises and • 64 bytes of user RAM Con2 - 2-pin male/female Berg developed by the author microcontrollers, which supply, microcontroller, relays, relay connectors the door gets locked again. If the entered • 15-stage multiple-function timer driver, alphanumeric Out of eleven I/O pins, seven lines - 7-pin male/female Berg password is correct the unit gives three display, keyboard and small beeps, and if the entered password is have been used for the keyboard, one for connectors memory. The power SW1-SW12 - Tactile keyboard switch wrong it gives a longer beep of one second. the buzzer, one for relay operation, and RL1 (RLY1) - 1C/O, 12V, 250-ohm supply circuit is shown The system uses a compact circuitry two (SCL and SDA, i.e. serial clock and miniature relay in Fig. 2. built around Motorola’s MC68HC705KJ1 serial data lines) for communication with The control unit microcontroller and a non-volatile I2C I2C EEPROM. uses low-cost, readily EEPROM (ST24C02) capable of retaining I2C memory. A two-wire serial EEPROM ible 2048-bit (2-kbit) EEPROM is organised available components. (ST24C02) is as 256x8 bits. It can retain data for more The temperature con- used in the than ten years. Using just two lines (SCL trol section has not circuit to re- and SDA) of the memory, the been included in the tain the pass- microcontroller can read and write the design as the parts re- word and the bytes corresponding to the data required quired are expensive relay-activa- to be stored. and not easily avail- tion time du- (Note. For details of the microcontroller able. However, a low- ration data. and programming of I2C EEPROM, you may Data stored refer to the article ‘Caller ID Unit Using cost thermostat used in remains in the Microcontroller’ published in April ’99 is- water heaters can be memory even sue of EFY and the article ‘Remote-con- Fig. 1: Block diagram of the beverage vending machine controller used in the unit. after power trolled Audio Processor Using Power supply. The Microcontroller’ published in Sep. ’99 is- failure, as the relays need 12V DC memory en- sue of EFY. For additional data on Motorola and the microcontroller sures reading microcontrollers, refer to EFY-CDs of this and memory need 5V of the latest year’s January and February issues. The DC for operation. saved settings information pertaining to I2C EEPROM is Bridge rectifier, capaci- by the available on STMicroelectronics’ Website.) tive filter and regulator microcontroller. Power supply. The power supply unit ICs 7812 and 7805 are This I 2 C provides a constant 5V supply to the en- the standard parts used Fig. 1: Block diagram of the access-control system bus-compat- tire unit. This is a conventional circuit us- in the power supply. Microcontroller. 50 ELECTRONICS FOR YOU OCTOBER 2002 Fig. 2: Power supply circuit We need individually WWW.EFYMAG.COM ELECTRONICS FOR YOU • OCTOBER 2006 • 77 CMYK
  • 5. Me - Personal Married. Stay in Noida with Wife Geeta, Daughter Upasana and Pet Maggie. When I got married - I did not own shoes - made millions - lost every thing - did not give up - asked for help - now back to profits.
  • 6. About Embedded Today for each PC there are 49 small tiny size micro controllers. Every thing from Lamps, Fans, Chimneys to Bikses, Cars, Traffic Lights, Elevators, Battle Tanks, Missiles use them. There is a huge demand for local/ regional products. This can not be supplied by large companies/imports.
  • 7. More about embedded This needs three things - Electronics - Soft ware - Creativity - Imaginations
  • 8. How will it help you This is part of your project. You need to it. Knowledge will be useful in which ever field you work. You will be using embedded devices. Skills are required if you wish to join core technical company.
  • 9. Problems New models of PC, Mobiles, Cars ... are available every year. Unfortunately, college syllabus stills includes obsolete devices that I read 31 years back. In a job with embedded company, your boss may ask you to unlearn what ever you know and then start learning again.
  • 10. Why I am here To share about a project and ask you to work with me
  • 11. Joy-n-Freedom We use electonics for luxury and convenience. Persons who are differently abled or sick or old have limitations. They and their familis are under stress. We wish to work on creating electronics projects for them and add Joy-n-Freedom in their life
  • 12. What we have done Participated in t wo events First one at National Blind School, Delhi. Second at Viklang Kendra, Allahabad Interacted with persons with disability, their family members and NGOs. There is a need and no supplies. Imported devices are too expensive
  • 13. Invitation Work me with me on projects. Work alone, as a team, in technical field, non-technical field, just support, feedback, share the concept, develop website or what ever you can.........
  • 14. Embedded Platform Embedded devices are available from multiple sources like Philips, Motorola, Renesas,ST Micro, Micro chip and so .... We can use of any of them, however each device needs specific tools and compilers and and some time on learning specific details. More than technicals it is the support from supplier of embedded devices that
  • 15. Our Choice I have work on NXP (Philips), Freescale (Motorola), Renesas(Hitachi), Microchip, ST, Zilog, Atmel. My choice is Freescale(Motorola) and Atmel. Both of them offer good developent support. You get quick results.
  • 16. Freescale Freescale has some India Specific Micro controllers. Compilers is Code warrior 6.3 Devices are 9S08IA, 9S08IB and 9S08IC
  • 17. ATMEL Compiler is ARDUINO Devices are ATMEGA168 Demo boards are available locally.
  • 18. Projects to be made Interfacing landline with TV Talking clock Universal remote for lights, fan, t v, air con, telephone, mobile Audio Visual Alerts for medicines Collection of Vital Stats and updating records. Alerts in case of serious issue
  • 19. Contact me name and email address by SMS to 9811074026 Send email to vinay@joy-n-freedom.com Visit my lab at Amity Incubator, Amity University, Noida
  • 20. Thanks for your valuable time.....
  • 21. CONSTRUCTION CONSTRUCTION Caller-ID Unit Using transmit the telephone number of call- ing party just before the first ring while in systems used in USA and China, the data relating to the calling number is Micro-controller sent between first and the second rings. The number of calling party in India is transmitted by MTNL/DoT exchanges in DTMF codes. LON Two documents containing stan- DHIL A.P.S. dards and specifications issued by DoT’s VINAY CHADDHA Telecommunications Engineering Cen- tre (TEC) in the form of ‘Generic re- T he facility of knowing your tended to the normal telephone users quirements’ and ‘Interface require- caller’s telephone number before also in Delhi, Mumbai and some other ments’ for ‘Subscriber service unit for answering the call, which has cities of India through MTNL and DoT calling line identification presentation been available to cellular phone users since 1st January. (SSU for CLIP)’ are available from TEC, only in India so far, has now been ex- MTNL/DoT telephone exchanges Khursheed Lal Bhawan, Janpath, Fig. 1: Complete circuit diagram of caller-ID unit 44 ELECTRONICS FOR YOU APRIL '99 CMYK
  • 22. CONSTRUCTION Remote-controlled centre values of treble, balance and bass. Volume will be set at 50 per cent of the maximum value and the relay Audio Processor Using will be off. Loudness and mute will also remain in the off mode. A remote hand- set can be used to change the settings as desired. Microcontroller Audio controller. TDA7315 is a single-chip I2C bus-compatible audio controller which is used to control all functions of the audio amplifier. Stereo audio input from the preamplifier is fed OO to the IC input. A microcontroller can SAG VINAY CHADDHA G.S. PARTS LIST Semiconductors: M IC1 - TDA7315 digitally controlled ost hi-fi audio CD systems and 3. audio processor nowadays are available with IC2 - MC68HC705KJ1CP Motorola remote control. However, no microcontroller (GVC-AMP- such circuit is available for adding to Description 257) IC3 - 24C02 I2C serial EEPROM the AF power amplifiers made as hobby Memory. 24C02 is an I2C bus compat- IC4 - 7805 fixed regulator +5V projects. The design of such an add-on ible 2k-bit EEPROM, organised as 256 IC5 - 7809 fixed regulator +9V circuit along with remote control is pre- x 8 bits. It can retain data for a period IC6 - µPD6121 infrared remote sented here. It can be used by hobby- of more than ten years, including the control T1,T2,T3 - BC547 npn transistor ists as an attachment to their audio current settings of volume, treble, bal- T4 - 2SC2001 npn transistor power amplifiers. ance, bass, as well as the on/off status D0-D7 - Red LED This design is based on audio con- of the main amplifier unit or the relay D8, D10-D11 - 1N4007 rectifier diode troller TDA7315 from SGS-THOMSON status. The various audio parameters D9 - 8.2V,0.5W zener can be stored in just six bytes. D12 - IR LED and Motorola microcontroller MC68HC705KJ1. The microcontroller, Mains power failure is quite com- Resistors (all 1/4W, ± 5% metal/carbon film, unless stated otherwise) after programming with the specific mon in India. This does not allow the R1,R2,R15,R16- 10-kilo-ohm software code for the current applica- last settings of volume, tone and bal- R3,R4,R14 - 1-kilo-ohm tion, has been renamed GVC-AUD- ance to remain intact. To overcome this R0,R5-R9, 257. Other construction projects by the microcontroller unit (MCU) must R12,R13 - 330-ohm the author using the same series of store all audio settings of the user in R10,R11 - 5.6-kilo-ohm memory (EEPROM). The memory en- R17 - 2-ohm, 0.5W microcontrollers, which can be referred R18,R19 - 200-kilo-ohm to for additional details, have been pub- sures that even after a power trip, the Capacitors: lished in EFY in Jun. ’97 (Set-Top Con- MCU will read the latest saved settings C1 - 10µF, 16V electrolytic verter) and Apr. ’99 (Caller ID). In ad- from the EEPROM. C2-C4,C7, dition to audio controller and Using two lines, SCL (serial clock) C19,C20 - 0.1µF ceramic disc microcontroller the circuit comprises and SDA (serial data), the microcon- C15,C16,C9, the following standard parts that are troller can read and write six bytes for C10,C11,C13 - 0.1µF polyester C5,C6 - 33pF ceramic disc used in any normal system: all the audio parameters. For more de- C8 - 22µF, 25V electrolytic 1. Power supply tails on I2C bus and memory interfac- C12,C14 - 2.7nF polyster 2. LED indicator panel to indicate ing, please refer to Caller ID construc- C17,C18 - 2.2µF, 16V electrolytic status/keys pressed tion project in Apr. ’99 issue of EFY. C21,C22 - 220pF ceramic disc At power ‘on,’ the last-saved audio C23 - 10µF, 50V electrolytic 3. Relay to switch on/off the supply to the power amplifier or the main unit settings are read by the MCU. In case Miscellaneous: memory IC cannot be read by the RL1 - 12V, 150 ohm, SPST relay The following parts are used in re- OEN Pt. No. 57DP-12-1C6 mote systems for VCR, TV, etc: microcontroller, volume LED will blink XTAL - 4MHz quartz crystal 1. Memory (24C02). three times to indicate the problem. The Y - 455kHz, ceramic resonator 2. Remote handset with 12 keys possible reasons could be either a bad - Battery 1.5V, pencil cell 3. IR receiver for remote operation memory IC, or a discontinuity/shorting - IR sensor module - Remote control handset, Functionality of these parts is ex- of its tracks, or improper insertion of complete with keyboard plained below with reference to Figs 1 the IC in its socket. - Connectors for audio input- The author is the proprietor of GVC Systems, Under the circumstances, the unit output and power supply will still work, but it will not remem- - 12V DC, 250mA battery Noida. He can be approached through e-mail eliminator at gvc@vsnl.com ber the last settings and will select the 52 ELECTRONICS FOR YOU SEPTEMBER '99
  • 23. CONSTRUCTION BEVERAGE VENDING MACHINE CONTROLLER SANI TH EO VINAY CHADDHA rants and even in companies. Press a allow compact size, higher reliability, switch and the machine delivers a hot lower cost and multiple functionalities. B everage vending machines are cup of your favourite drink. This tea/coffee/soup vending ma- commonplace at railway sta- This looks quite a simple operation chine controller uses Freescale’s latest tions, airports, fast-food restau- but has a very complex logic behind MC908JL16 microcontroller chip. The it: It involves use of controller is programmable and user- twelve precision timers friendly. You can set the quantity of and four counters apart the beverages through a button switch from physical devices like provided on the front panel of the con- display, solenoid and mo- troller as per your requirements. Thus, tor to deliver water and cups of any size can be filled at any premixed tea/coffee/soup time. powder in exact quantity for better taste and in ex- The hardware act sequence. Fig. 1 shows the block diagram of the This has become pos- vending machine controller. It com- sible because of the use of prises the following sections: power The prototype of beverage vending machine controller developed by the author microcontrollers, which supply, microcontroller, relays, relay driver, alphanumeric display, keyboard and memory. The power supply circuit is shown in Fig. 2. The control unit uses low-cost, readily available components. The temperature con- trol section has not been included in the design as the parts re- quired are expensive and not easily avail- able. However, a low- cost thermostat used in water heaters can be Fig. 1: Block diagram of the beverage vending machine controller used in the unit. Power supply. The relays need 12V DC and the microcontroller and memory need 5V DC for operation. Bridge rectifier, capaci- tive filter and regulator ICs 7812 and 7805 are the standard parts used in the power supply. Microcontroller. Fig. 2: Power supply circuit We need individually WWW.EFYMAG.COM ELECTRONICS FOR YOU • OCTOBER 2006 • 77
  • 24. CC O NTS T RTU O N I O N ONS RUC I CT MICROCONTROLLER-BASED IL KU MAR ACCESS CONTROL SYSTEM SUN VINAY CHADDHA* the password data for over ten years. PARTS LIST The user can modify the password as S Semiconductors: ecurity is a prime concern in our day- well as relay-activation time duration for IC1(U1) - MC68HC705KJ1 to-day life. Everyone wants to be as door entry. This version of software microcontroller much secure as possible. An access- enables use of the unit even without the IC2 (U2) - ST24C02 I2C EEPROM control system forms a vital link in a secu- I2C EEPROM. (However, without EEPROM, IC3 (MN1) - MN1280 reset stabiliser rity chain. The microprocessor-based digi- the password and relay-activation time IC4 (Reg1) - 7805 +5V regulator tal lock presented here is an access- duration will be reset to default values T1, T2 - BC547 npn transistor (Q1, Q2) control system that allows only authorised on interruption of the power supply.) D1, D2 - 1N4007 rectifier diode persons to access a restricted area. LED1 - Red LED Hardware details Resistors (all ¼-watt, ± 5% carbon, unless System overview Fig. 2 shows the access control circuit. Its stated otherwise): R1-R6 - 10-kilo-ohm The block diagram of the access-control main components are a microcontroller, R7-R9 - 1-kilo-ohm system is shown in Fig. 1. The system I2C memory, power supply, keypad, relay, Capacitors: comprises a small electronic unit with a and buzzer. C1, C2 - 33pF ceramic disk numeric keypad, which is fixed outside the M ic r ocon t r olle r . The 16-pin C3, C4, entry door to control a solenoid-operated MC68HC705KJ1 microcontroller from C6, C7 - 0.1µF ceramic disk lock. When an authorised person enters a Motorola has the following features: C5 - 10µF, 10V electrolytic predetermined number (password) via the • Eleven bidirectional input/output Miscellaneous: keypad, the relay operates for a limited time (I/O) pins Xtal (Y1) - 4MHz quartz crystal to unlatch the solenoid-operated lock so the • 1240 bytes of OTPROM program PZ1 (BZ1) - Ceramic piezo buzzer door can be pushed/pulled open. At the end memory Con1 - Power-supply connector of preset delay, the relay de-energises and • 64 bytes of user RAM Con2 - 2-pin male/female Berg the door gets locked again. If the entered • 15-stage multiple-function timer connectors password is correct the unit gives three Out of eleven I/O pins, seven lines - 7-pin male/female Berg connectors small beeps, and if the entered password is have been used for the keyboard, one for SW1-SW12 - Tactile keyboard switch wrong it gives a longer beep of one second. the buzzer, one for relay operation, and RL1 (RLY1) - 1C/O, 12V, 250-ohm The system uses a compact circuitry two (SCL and SDA, i.e. serial clock and miniature relay built around Motorola’s MC68HC705KJ1 serial data lines) for communication with microcontroller and a non-volatile I2C I2C EEPROM. EEPROM (ST24C02) capable of retaining I2C memory. A two-wire serial EEPROM ible 2048-bit (2-kbit) EEPROM is organised (ST24C02) is as 256x8 bits. It can retain data for more used in the than ten years. Using just two lines (SCL circuit to re- and SDA) of the memory, the tain the pass- microcontroller can read and write the word and the bytes corresponding to the data required relay-activa- to be stored. tion time du- (Note. For details of the microcontroller ration data. and programming of I2C EEPROM, you may Data stored refer to the article ‘Caller ID Unit Using remains in the Microcontroller’ published in April ’99 is- memory even sue of EFY and the article ‘Remote-con- after power trolled Audio Processor Using failure, as the Microcontroller’ published in Sep. ’99 is- memory en- sue of EFY. For additional data on Motorola sures reading microcontrollers, refer to EFY-CDs of this of the latest year’s January and February issues. The saved settings information pertaining to I2C EEPROM is by the available on STMicroelectronics’ Website.) microcontroller. Power supply. The power supply unit This I 2 C provides a constant 5V supply to the en- Fig. 1: Block diagram of the access-control system bus-compat- tire unit. This is a conventional circuit us- 50 ELECTRONICS FOR YOU OCTOBER 2002

×