http://www.8051projects.net/ Learn to make simple microcontroller projects, pic, 8051, avr and arm projects. download 8051 projects, tutorials, libraries, sample codes. join the microcontroller discussion forum and ask doubts regarding electronics. the best source for 8051 over internet. en-gb 2009-01-07T22:17:50-08:00 contact@nospam.com hourly 1 2000-01-01T12:00+00:00 http://www.8051projects.net/forum-t7669.html 2009-01-07T22:17:50-08:00 this thread is to complement http://www.8051projects.net/forum-t7667-last.html please post your doubts aboutsmoothening techniques here http://www.8051projects.net/forum-t7669.html 2009-01-07T22:17:50-08:00 shyam barrel shifter mechanism is way too ahead of all these techniques i am taking u there one by one..yes we are intro ducing incorrect data... thats why i said it shud not be implemented thru software but mostly thru hardware!!! http://www.8051projects.net/forum-t7669.html 2009-01-07T22:17:50-08:00 Amit Radha Hmmm... I am waiting eagerly to learn more... pls do post soon... thanks alot!!! http://www.8051projects.net/forum-t7669.html 2009-01-07T22:17:50-08:00 sashijoseph Ajay wrote ...you must click on thanks button Done dude......now Amit's turn http://www.8051projects.net/forum-t7669.html 2009-01-07T22:17:50-08:00 Amit Radha He he http://www.8051projects.net/forum-t7669.html 2009-01-07T22:17:50-08:00 Amit Radha Hi shyam,Is this the thread you mentioned? Good idea! But please do post something soon.. am waiting eagerly. And if possible do include help in assembly and not only C. Will be a huge help for noobs like me http://www.8051projects.net/forum-t7669.html 2009-01-07T22:17:50-08:00 shyam please visit..http://www.8051projects.net/forum-t7667-last.htmlthis thread is only to discuss the doubts regarding the above link http://www.8051projects.net/forum-t7669.html 2009-01-07T22:17:50-08:00 Amit Radha Hey Shyam, the concept is good. but how do u implement that using a uC? and the link is closed. cant post anything in that so i posted here... http://www.8051projects.net/forum-t7669.html 2009-01-07T22:17:50-08:00 shyam keep reading!!!..and yes u cant post there so all doubts will be solved here..well implementing the sample hold technique can be done thru a micro controller it is easy!!!...but it is like fooling your client this is the way to do it..all you need is to make the changes in the ADC data a little slower!!..step1 . set interval for sampling.. suppose 1 sec..step2 set interval to display data.. assume u r making a graph so points per sec suppose 5.step3. read data @ADC at sampling rate...step4 .no need to read the next 4 values simply copy the values to the next 4 variables.. repeat step3 and 4.ex..sample 1 =0 sample 2 =1 sample 3 =2 sample 4 =3 sample 5=2 sample 6 =1 sample 7 =0u will get the following representation ***** ***** ____***** *****_______________**********__________________________*****012345678901234567890123456789012345thus you will get a theoritically smooth looking graph but practically it is useless...therefore sample and hold technique is seldom used in softwares/codes... it is mostly an hardware implementation...simplest S&H mechanism is the operation of a capacitor..u can add a capacitor into your input(adc) to get the S&H response.keep reading as i will be posting more techniques.. http://www.8051projects.net/forum-t7669.html 2009-01-07T22:17:50-08:00 sashijoseph Nice explanation Shyam........ http://www.8051projects.net/forum-t7669.html 2009-01-07T22:17:50-08:00 Ajay you must click on thanks button http://www.8051projects.net/forum-t7669.html 2009-01-07T22:17:50-08:00 Amit Radha Hey Shyam thats really nice! Could never think of that. Well now i know the difference b/w having a theoretical knowledge and its practical implementation!But I have a doubt. By copying the data to then next 4 variables, arent we introducing incorrect data there as there is a possibility the ADC o/p may have changed at that instant. Also, can this be used as a replacement to the barrel shift algorithm u mentioned earlier?By using a capacitor before the i/p of ADC will surely help smoothening out the variations! Il try that for sure!!!Thanks a million!!! http://www.8051projects.net/forum-t7669.html 2009-01-07T22:17:50-08:00 pdi33 very good info in the forum. another interesting application (which uses the exact inverse principle)of the above method is the oversampling technique used to increase the resolution of the ADC. this is well explained in AVR application note AVR121. It uses oversampling to increase the resolution for its inbuilt adc from 10 bit to 16 bit by introducing a fixed noise source. It could well be used in slower systems like temperature but the ADC conversion should be really fast.check this file outhttp://www.atmel.com/dyn/resources/prod_documents/doc8003.pdf