This section includes the answers of some of the questions that are usually asked by hobbyist or professionals. This is the humble effort from the sight owner to satisfy their demands. If you need any more/other information feel free to write at a_m_bhatt@indiatimes.comor directly contact to +91-9998476150   

Que) what is an embedded system?

Ans) its complete system or part of complete system with micro controller / micro processor based hardware and embedded software, design to perform one or more particular task(s).

Que)   What is the range of normal IR remote control ?

Ans:    normally the range of every kind of IR remotes are limited to 10 meter. 

Que)   Why IR remotes are mostly used in home application like for TV, A/c, music system etc ?

Ans:     it requires less voltage (around 3 V) and consumes less power. It is small and handy also in home you don't need more range.

Que)   Why IR remotes are usually not used in industrial application ?

Ans:    First and the most oblivious reason is limited range. Second reason is directivity.

Que)   Why AM is not utilized for remote control application though it has highest range ?

Ans:     Particularly AM is suitable for voice and audio communication only. It is not suitable for signal or data communication because of lots of noise and possibilities of errors.

Que)  What is PLL 567 ?

Ans:   It is phase lock loop chip. It locks the incoming phase and produce the low o/p when a perfect match is found. the freq of operation is selected by RC components.

Que)   Why the range of FM remote is limited to 500 meter when all the FM Radio stations has the range of 40 to 60 Km ?

Ans:    All the FM radio stations acquires high power FM transmitter so obliviously their ranges are high also the second reason is in remote applications we are transmitting and receiving signals not the voice or audio frequency. So for getting noise free signals one has to compromise with range.  

Que)  What is HT12E and HT12D ?

Ans:   Both are RF encoder and decoder chips specially designed to establish proper protocol between Transmitter and receiver so that one can achieve noise free data communication.

Que)  What is SM5032 and SM5021 ?

Ans:   These are IR encoder decoder chips. Encoder will generate a specific code for each key pressed and transmit it on IR channel by modulating it over 38 KHz frequency. Decoder will decode the code and gives pulse o/p on its pins

Que)  What is MDT & MDR ?

Ans:   These are specially designed RF serial data transmitter and receiver. MDT will modulate the incoming data with 433.92 MHz carrier freq and transmit it. MDR will receive this signal demodulate it and recover the data.

Que)  Where can I get HT12E & HT12D ?

Ans:  Vendor's Address : APLUS India, Gnd floor Bakul bag, S.V.Road Santacruz, Mumbai-54: www.aplusindia.net

Que)   Where can I get SM5032 & SM5021 ?

Ans:  Vendor's Address : APLUS India, Gnd floor Bakul bag, S.V.Road Santacruz, Mumbai-54: www.aplusindia.net

Que) Whare can I get MDT & MDR ?

Ans:and other address same as above.

Que) Can you suggest any reference books for micro controller 8051 ?

Ans: Here are some of the reference books 1) 8051 micro controller architecture, programming and application by K.J.Ayala : Penram International Pub. 2) The Micro controller Idea book by Jen Axelson : Penram International Pub. 3) Micro controller Basics and projects by Myke Predko :  Tata Mcgrowhill pub. 4) 8051 micro controller and embedded system by M A Mazidi: Pearson education

Que) Where can i get the pseudo codes for 8051 programs ?

Ans : One has to develop these codes himself. The idea is given over here and one has to try to develop the code.

Que) Why shoud we use 89C51 instead of 80C51 ?

Ans: 89C51 has an EEPROM and 80C51 has simple EPROM. So you can program 80C51 only once while 89C51 can be programmed many times

Que) How can I program the micro controller 89C51 ?

Ans: You need an Atmel programmer to program 89C51. Also one can use any EPROM Programmer to program it. First one has to write assembly language program on any suitable platform which supports 8051 ALP. Then by compiling this file he has to generate an object file. At last by running this object will generate HEX equivalent file and that should be downloaded in 89C51.