Newbie question - USB or Parallel Port?

[aljaffee]

Hi, I am new to this board and want to thank everyone in advance for reading this question and for any input you can give.  I want to make an industrial robot, that is a robot that will help me assemble a product.  I am a computer programmer but have no experience yet with robotics.  This robot will always be wired to a laptop or PC (unless bluetooth makes more sense and if it does, please enlighten me).  From what I have read so far on the internet, I will need to control/receive data back from the robot via the parallel port of the laptop or PC.  My question is, can I use a USB port instead (my current laptop does not have a parallel port and I don't know if I need to order online a parallel port to USB adapter or not first)?  What are the advantages and disadvantages of each?  Which is easier to program or setup?  

There is one thing you should know as well.  I am planning on having maybe like 50 different motors/servos in this robot.  Would I have to use multiple parallel/usb ports to accomplish this?

There is one more thing that you should know, datawise.  Aside from the physical movements I want my robot to perform, I would ideally like to incorporate a sensor that could detect a range of say, 50 different colors.  Would this be possible using a parallel port or would it be too much data that would have to flow in this process for a parallel port to be practical, thus forcing me to use a usb port?  Sorry if I am not using the correct terms to describe this or if I am missing some big piece or step here.  Like I said, I am completely new to this and still learning what I need to gather to get this project started.  I used to build radio control cars about 20 years ago with Tamiya kits and radio control units that used servos (brands like Accoms, Futaba, etc.).  I don't know if servos can be used at all anymore with modern robots or there is some kind of new technology that has surpassed servos, nor do I even know if companies like Futaba are around anymore.  I only mention this because I am on a limited budget and where possible, I would like to use/re-use things I already have (e.g. use the innards of 2 HP printers for an X and a Y axis linear actuator (if that is the correct term)).  Thanks again.

[SmAsH]

well, each has its own advantages.
we all know that only dinosaur like computers have parallel ports and that usb is the new rage,
everything from phones to mice use usb these days...

i have heard that parallel port to usb cables do not work for some reason of other but i think
you will need to google to confirm...
how will your robot be communicating with the computer? through programmer ports or uart?

you spoke about wireless... this has many advantages such as not dragging a giant cable behind your robot,
not many length restrictions, can go through walls lots of things. although this method is more expensive
it can be better. ask yourself, where will my robot be going?
is it going to be sitting right next to your pc or running around all over the place while connected?

there is one thing i will need to know is how the robot will be connected.
will it be through the rx/tx pins on the mcu or through a programmer?

[aljaffee]

Hey SmAsH, thanks for the response.  Yeah, I don't need wireless.  The robot will/can always be next to the computer.  This robot is stationary - it has no wheels or anything - it is not really like most of the robot projects I have seen on the internet that are autonomous vehicles that run around avoiding walls.  This is an industrial automation robot.  A piece of factory equipment.  It just needs to move a lightweight plastic plate on 2 axes - along an X axis and along a Y axis.  Mounted above all this will be a unit that will just move straight up and down and make markings on the correct spots on the plate.  I guess I only asked about bluetooth because I didn't know if there was any other compelling reason (aside from mobility) why I would need to use that.

Now, about connection.  This is where I am not sure about.  Is there no way to solder wires to parallel port pins or is that not advisable?  When you mention receiving and transmission pins on the MCU - are you talking about parallel port pins?   Does MCU mean microcontroller unit?  From what I just read on Wikipedia it sounds like a simple kind of microprocessor.  Is it that the Intel chip/motheboard in my laptop cannot perform this role?   Note, that my plan was for the laptop computer connected to this robot to be the brains of the whole thing.  I didn't plan for there to be any kind of processor inside the robot itself.  Or does it need one?  Also, I am not sure what a "programmer" is either as you mention.  If I have to build any kind of electronic boards myself, that I have no problem doing.    Thanks.

[SmAsH]

ahh ok, i see what you mean now.
for this "robot" do you want it to be controlled by itself, like with no external circuitry?
or do you want your pc to do all the work?
mcu stands for microcontroller unit. do you know the name of your main chip that you are using?
is the thing you are making like a mill kind of setup?

[GearMotion]

The robot will/can always be next to the computer.  This robot is stationary - it has no wheels or anything - it is not really like most of the robot projects I have seen on the internet that are autonomous vehicles that run around avoiding walls.  This is an industrial automation robot.  A piece of factory equipment.  It just needs to move a lightweight plastic plate on 2 axes - along an X axis and along a Y axis.  Mounted above all this will be a unit that will just move straight up and down and make markings on the correct spots on the plate.  I guess I only asked about bluetooth because I didn't know if there was any other compelling reason (aside from mobility) why I would need to use that.

Now, about connection.  This is where I am not sure about.  Is there no way to solder wires to parallel port pins or is that not advisable?  When you mention receiving and transmission pins on the MCU - are you talking about parallel port pins?   Does MCU mean microcontroller unit?  From what I just read on Wikipedia it sounds like a simple kind of microprocessor.  Is it that the Intel chip/motheboard in my laptop cannot perform this role?   Note, that my plan was for the laptop computer connected to this robot to be the brains of the whole thing.  I didn't plan for there to be any kind of processor inside the robot itself.  Or does it need one?  Also, I am not sure what a "programmer" is either as you mention.  If I have to build any kind of electronic boards myself, that I have no problem doing.    Thanks.

You should take a look at RobotBASIC - free development software that runs on the PC ( http://www.robotbasic.org ) that can control U401 or U421 USB devices ( http://www.circuitgizmos.com/products.shtml ) tethered to a PC. RobotBASIC is a great language for developing robot control on the PC and controlling tethered robots.

[aljaffee]

SmAsH,

I don't want the robot to be controlled itself.  I want it to always be attached to a laptop that will control it (i.e. have the laptop do all the work).  If that is not a good idea, please let me know why or what I need to consider.

Sorry, I am still unclear as to what microcontroller unit is - also when you say "main chip" I am not sure what to say.  All I know is that my laptop has a Pentium Dual Core.

Yes, this will be kind of like a "mill" as you say.

[aljaffee]

GearMotion,

Thanks a lot for the link.  This looks great and might be just what I need.  I will look into it more.  Thanks again.

[SmAsH]

ok,
so for this project your pc will be the "microcontroller",
if you need precision take a look at stepper motors as they are very accurate and have great torque.
you may want to take a look at widgets boards, they allow control of I/O lines via usb port.