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Thread: obstacle avoidance module

  1. #11

    Default clarification

    Its not easy to measure time taken by light to reflect back. Say ur uC is clocked at 16Mhz. so the least measureable unit of time is 1/16000000 s. in that time light can travel upto 18.75 meters. so the accuracy is plus or minus 18.75 meters !!
    Oopsssss... ultra sonic is a sound wave and not a Electromagnetic wave...... so it moves in the speed of sound.... and not the light.... Okkk

    compare the waveform's frequency and when you get an exact replica of the transmitted wave ( you gotta tune your circuit for that).. thats when you measure delay. and believe me.. that takes time..
    I am not getting....what u mean.......

    else rangefinding wouldnt have been there,,,
    Range finding in engineereing (let us say constrution and millitatry) genrally use... TOF method (time of flight).. but when they want accuracy they use the difference in phase change
    and calculate it......

    I think D misconception are now cleared...


    Quasar..

  2. #12
    Administrator T-1000 rao's Avatar
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    Default

    Ok ..

    someone finally replied to this thread..


    Speed of sound.. thats right...

    Yeah.. by tuning the ckt I meant removing phase shift or calculating it(I know 567 does that, and I usually use 567..).. Other wise using a comparator with a test frequency also gives the proximity..

    Thanks for answering!!

    Rao

    P.S. that ws a serious thanks and not sarcastic

  3. #13
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    i used a srf04 sonar module by devantech...
    works gr8 for gud distances...
    if u thought u r the only mad person on the planet.......u got serious competition here

  4. #14
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    check out www.hobbykits4u.com
    they seem to have gud modules....
    if u thought u r the only mad person on the planet.......u got serious competition here

  5. #15

    Default hi guyz

    hmm for a newbie as u said bump sensors wud be good enuf but thats gud if you dont mind colliding wid the object n den reversing.

    ir sensors as said has the problem of colours but is gud in the sense as it does not require you to hit the obstacle to find out about it.the good thng here is it can be made to work for very small distances.

    ultrasonic sensors as they say is meant for long range distance finding n can be used for obstaclke finding too.but cant find out small distances very accurately.it is more useful in cases of range finding n stuff.

    n ya if u r a newbie n looking for some readymade stuff of ir n ultrasonic sensors in india then maybe u cud get in touch with a company called

    ROBONENCE ph 080-41526083 Contach person MR suraj

    they will definately help you with all this.

  6. #16
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    hi taknev....
    ir's doesn fails completely for black surfaces....
    they ll be detected but the range drastically decreases....
    and they ll be surely detected if the surface is shinny....
    if u thought u r the only mad person on the planet.......u got serious competition here

  7. #17

    Default hi

    ya addy thats wot i meant it works the exact way u said.

    cannot express evrythng n words

  8. #18
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    hi taknev.....
    yeah u r correct....
    i said man tat it doesn gives the desired response as u ll expect... tats it!!
    but still if u r measuring the time gap between the 'ping' and time u recive it back.... then u can 'exactly' predictly distance and then it ll work fine giving u corect distance between the obstacle and the robo..
    if u thought u r the only mad person on the planet.......u got serious competition here

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