How to connect and control a stepper motor and sensor connected to laptop using matlab?

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Kevin 2012-11-22

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https://ww2.mathworks.cn/matlabcentral/answers/54444-how-to-connect-and-control-a-stepper-motor-and-sensor-connected-to-laptop-using-matlab

I have a stepper motor with driver and a through beam sensor, when an object passed my sensor I would like my program to run and the motor will also run by 90 degrees counterclockwise then after the object passed the second sensor my motor will turn clockwise again by 90 degrees. can anyone help me how to connect this using parallel port and the code for it? Thank you very much hope someone helps

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Walter Roberson 2012-11-22

Which operating system and MATLAB version are you using, and are you using 32 bit or 64 bit MATLAB?

Newer versions of MS Windows have made it technically difficult and slow to access the parallel port. It is recommended that you do not start any new projects using the parallel port.

Kevin 2012-11-24

I have windows xp with Matlab 2010, I am also running it in 32 bit.

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Walter Roberson 2012-11-24

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https://ww2.mathworks.cn/matlabcentral/answers/54444-how-to-connect-and-control-a-stepper-motor-and-sensor-connected-to-laptop-using-matlab#answer_66344

There is a code output at http://www.mathworks.com/matlabcentral/answers/40042-how-to-input-data-from-data-port-of-lpt

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Walter Roberson 2012-11-24

If you use that architecture, then you need to have a program running and actively checking the port status periodically, and initiating action when it detects the presence of the object.

I recommend that you calculate how long a car would be in range after the sensor was triggered, so that you can determine the maximum processing latency. Taking into account that cars speed. How long does it take to start MATLAB? How long would it take, once in MATLAB, to capture and read the image? Does the ANPR need to be done by the time of the next car, or can it be done "at leisure" ? Or are the plate pictures to be taken and stored, and ANPR is to be done based on the recorded pictures?

I suspect you will find that you do not have the luxury of starting your MATLAB program when the sensor detects a car: I suspect you will find that the MATLAB program has to be ready and waiting, and probably even has to be the program which is scanning the parallel port to detect the car interrupting the beam.

Walter Roberson 2012-11-25

If you were doing license plate recognition on a highway, you would have only on the order of 20 milliseconds to do the detection and take the picture. Your choices would be bound by the performance requirements. But in your actual situation, you can afford to keep the driver waiting a few seconds, during which time the car is not going to move more than a few feet (if at all.) Your performance requirements are lax.

The link at the top of my Answer gives you the code outline of how to talk to a parallel port. The diagram you posted the link to gives an idea of how to drive the motor with the parallel port. For the sensor input, I recommend you connect the wire (ummm, the positive I think) to the Select pin of the parallel port. You need to read the control port to read that input, but that is pretty much standard for input from parallel ports and you should be able to find examples of that.

The ANPR part is something I do not have the resources to get into at this time.

Walter Roberson 2012-11-25

编辑：Walter Roberson 2012-11-25

You are right about the TTL output.

The 1.5m is "maximum". Unfortunately for you, you need more than that if the vehicles are cars: you will need at least 1.8 meters (allowing for mirrors)

Is this intended to be outdoors? If so then you should reconsider use of an infrared system, as you can get stray IR due to sunshine or re-radiation from heated objects; you would also need to worry about mist and rain or fog (or even high humidity), which are going to cut down on the maximum distance. The less control you have over the working conditions, the more you need to over-engineer. You don't want your system to break down because the wind swept some damp snow up onto the sensor (or transmitter) and it clung there: you need the system to be robust enough that a signal can get through even if there is a layer of freezing rain. A radio-frequency sensor can be more effective in adverse weather; that or at least an optical system that can stand to lose a few decibels due to bad conditions. (Though if you do use a radio-frequency sensor, you need to take into account whether motorcycles or bicycles will block enough of the signal to be reliably detectable.)