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 Author: mongkiosk [ Wed Jun 02, 2010 1:22 am ] Post subject: servo control using potentiometer hello guysi am going to do my final year project regarding the servo controlbecause i am going to construct a robotic armbasically,i need some guides to do iti need some guidance how the potentiometer can control the servo rotation respectively by rotating the potentiometer probei've been watching some videos on youtube where got some people already succesfully do itso I really appreciate if someone can help me in thisroughly,i am going to do it using 8051 as the brain and for sure i need adc to convert the continuous signal from the potentiometer to digital signalthats the only basic thing i knowreally need some guidance from some experts here:cry:thank you very much~

 Author: mightor [ Wed Jun 02, 2010 3:59 am ] Post subject: Re: servo control using potentiometer mongkiosk,This isn't really NXT or ROBOTC related is it?I've never used an 8051, but I'll give you at least some theory of operation.Say you have an ADC (Analogue to Digital Converter) that is 10 bits, that means that you have 1024 steps that you can measure. Say you can rotate your arm 180 degrees and by doing so, the pot meter moves all the way from one end to the other. That means that for every degree the robot arm moves, the ADC will detect a change of 1024/180, which is roughly equal to 5. So if your ADC is giving you a reading of 760, that means the arm is at around (760/1024) * 180 = 134 degrees.ADCs come in many shapes and sizes. I am a big fan of the MAX127 because it has an I2C interface. I am not sure if I2C is the way you want to go, a simpler SPI version may be more useful to you. You're going to have to do some research yourself for that. It may also be a good thing to try and find a forum with 8051 programmers, they will be more able to help you with this.Regards,Xander

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