Point 1
You still have to know about data rates There is no point in designing a circuit that counts pulses unless you know what the data rate is
Why this is so important is because the application you are talking about will be cpu based that means that on a specific port pin of the cpu you will be looking for logic highs / lows start and stop bits depending on what format you use Clock synchronization if you need to derive a clock from the incoming signal and last but not least we get to subjects such as Manchester encoding CRC for checking parity no parity error correction particularly if you are dealing with RF based propagation also whilst mentioning propagation there are such other formalities such as propagation delay etc These all need to be taken into account
In your suggested application you will need to understand programming there is no other real method that is use today That means you will need to know about bit banging sampling incommoding signals at predetermined intervals to ensure you pick up on the incoming signal correctly
This also implies that you must be aware of instruction times for example you cannot write an infra red remote control sequence out unless you understand assembler and instruction times since the time delays btw logic ones start sequences end sequences are completely different
Even if you chose for example to use interrupts you must still pay very careful attention to instruction time
Example lets suppose you are looking at a pulse 0.5 us you would need at least 3 instructions to see if that pulse which in turn implies that on a 4 mhz crystal operated pick Each instruction will take 1mhz (Clock / 4 ) or 0.0000001 seconds (recall t = 1/f ) This is down to internal architecture of cpu internal pipelining, goto and return instructions and interrupts take two instructions
Thus even if you were to use a 4mhz pic micro your instruction time now becomes very important Reason is in the above example you are looking at 0.5 us pulse or logic high and your instruction time doesn’t even allow you to see this or detect this properly say your results are going to be out straight away
Point 2
One way or bi directional
Taking into account point 1 then even more importantly it becomes that much more apparent that if you were to use arbitration btw the sending and receiving device timing now becomes even more critical since you will need to use ack and nack positive acknowledgments and negative acknowledgements to let the sending device know that it needs to resend information be that a square wave or what ever variable mark to pace sequence of pulses data etc
Point 3
Coax or twisted pair
Here you need to consider point 1 point 2 and finally this important criteria since propagation delay comes into play How long does the signal take to reach the terminating device
Length of cable voltage on cable, resistance, impedance do you need to down convert will data be inverted non inverted how long will it take to ,convert bit errors
Point 4
DC power supply voltages
This covers driving circuitry Impedance matching again cpu operating voltage , cline conversion voltages from lets say rs232 , TTl logic time delays again and of course instruction time to read and count data
Looks easy
Your comments as follows , “Plus i dont know much about programming…. It will be helpful if you could somehow guide me to a circuit and source code for transmitting the pulse and obtain it in the same form at the receiver end so that the pulse could be checked on oscilloscope.”
But you do need to know about programming You do need to understand circuits You also need to understand transmission techniques You need to understand lots and lots and lots
So its not just can someone show give me a circuit and can someone give me the code and can someone just do all of this for me because I don’t know how too It’s a case of Yes lots of people can however Its also called time and knowledge to be able to achieve these requirements and its defiantly not that simple and its cost money my friend as I have said before time is money No one sits down and does this for nothing anymore the World does not allow this which it was that good but they don’t !!
All of us have to go away and do stack of learning to get this far and its in our own time we gave no choice we also just like you have bills to pay so far we are also stuck with people that actually think they are clever not paying thoes bills on time hence we no longer do things for nothing anymore We also just like everyone eles have to invest that means If they dont pay or you decxide you want this all for nothing No one can invest to give you that information Someone has to pay for this somewhere along the line be that books be that time to put up articles which we do do from time to time to help people but alas we cannot do this all the time
Sad old world im afraid
Still not to worry you can hwoever commence now its not to late and here is a page to start with
http://www.mhennessy.f9.co.uk/pic.htm ( which you should have taken the interest to learn some 15 /17 years ago or at least started and experimented with ) By now you shopuld be working with rasperri pi interactive gui mechanisms touch screens interactive control systems , networking principles the lot inclusive embedded linux getting your mobile smart phones to talk to applications , web based appliactions writing your own servers embedded servers , so that you can talk send messages across the cloud etc etc
Ps let me know how long it takes you to get all of this into your heads plus write the software plus draw the schematics plus make the printed circuit boards plus test this and finally produce this
Its only take me an entire lifetime to be even remotely competent and be able to deliver what some people are asking for and for that my friend I charge anything up to 1 months , 6 months , 2 years wages for and I expect to be paid for doing this on time every time without fail I don’t play games with people
Not your £30.00 story for 12 hours work lots of money to do things like this and understand them and make sure they work without failure
Its my living and intend to keep it that way as well and this in turn allows me to know when to tell a manufacturer / supplier to get stuffed because i don’t need them because i can do it myself without there co operation so believe you me the days when they thought they didn’t need to know and thought they were the only people who can do this are and answers of We don’t need to be helpful are long long over They do very much so there you go that’s what you can have and say back to the big shots if you work hard and back it up as well !!
