Society of Robots - Robot Forum
Mechanics and Construction => Mechanics and Construction => Topic started by: sandboxbuddy92 on October 31, 2009, 03:04:59 PM
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Here's a good idea of what I want it to look like (best way I can think of):
http://img.diytrade.com/cdimg/557732/3971434/0/1184596970/Moving_head_light_spot_1200W_stage_light_stage_lighting_LED_light.jpg (http://img.diytrade.com/cdimg/557732/3971434/0/1184596970/Moving_head_light_spot_1200W_stage_light_stage_lighting_LED_light.jpg)
I want to have a turntable thing that sits on the floor (like the picture), with with motorized....things.....that support the "light" (as in the picture).
I want to be able to set the speed of both motors described above using a computer, but I have no idea how. Also, I want to be able to have a sensor or something that can detect the angle of the turntable and support things somehow, and be able to receive that as input on a computer.
Instead of a light, like the picture, I want to have some sort of sensor that will emit a "sonar" type thing and give the computer the time that the sonar was fired and the time it was received.
Summary of Questions:
- How do I talk to motors and sensor with a computer?
- What kind of motors/sensors would I use for the robot described?
- How do I power this sort of thing?
- How would I get the necessary parts to build it (design them, order them, etc)?
I have a decent amount of software experience...but when it comes to actual robots I'm completely lost.
Any sort of references or something would be great. Feel free to answer whichever questions you wish.
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- How do I talk to motors and sensor with a computer?
Probably parallel or serial port would be the easiest. Or maybe uart?
What kind of motors/sensors would I use for the robot described?
Probably dc motors with encoders or steppers...
DC motors are easier to interface for someone new but will require encoders to give position feedback.
Steppers are more complicated to control but are much more accurate and need no position feedback to know their position.
- How do I power this sort of thing?
Well, if it was me, i would use a wall wart or similar, batteries seem like a bit of a waste if it is going to be immobilized.
- How would I get the necessary parts to build it (design them, order them, etc)?
For the electronics, a site such as futurlec/digikey would suffice.
But that is if you want to build the electronics yourself, if you cant be bothered and want to buy a premade board there are heaps of sites that offer such control boards, just Google!
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- How do I talk to motors and sensor with a computer?
Probably parallel or serial port would be the easiest. Or maybe uart?
What kind of motors/sensors would I use for the robot described?
Probably dc motors with encoders or steppers...
DC motors are easier to interface for someone new but will require encoders to give position feedback.
Steppers are more complicated to control but are much more accurate and need no position feedback to know their position.
- How do I power this sort of thing?
Well, if it was me, i would use a wall wart or similar, batteries seem like a bit of a waste if it is going to be immobilized.
- How would I get the necessary parts to build it (design them, order them, etc)?
For the electronics, a site such as futurlec/digikey would suffice.
But that is if you want to build the electronics yourself, if you cant be bothered and want to buy a premade board there are heaps of sites that offer such control boards, just Google!
OK.....I'm still pretty fuzzy, but I think I may have a few things down. I believe that I need a DC Servo, an encoder for the servo, and a stepper. If I understand correctly, to communicate with these things I need a "board" to plug all of these things in to, and computer software to tell the board what to do (I read "stamp" somewhere?). Does this sound correct?
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Ok, two options are:
1. board to communicate between pc and sensors, DC motor and an encoder + power supply etc...
2. board to communicate between pc and sensors, stepper motor + power supply etc...
Of coarse there and a lot more ways of doing this, im just outlining two that i think would be fairly easy for a person new into electronics.
The term "stamp", the first thing that pops into my head is the stamp dev board... I dont know if thats what your thinking?
For programming languages, i don't really have much experience with "on pc" languages so i cant help with that too much. But most of the standard usb interface boards will come with software to get you started whether it be a ready made program that you use or one where you code it yourself using their library of something...
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Ok, two options are:
1. board to communicate between pc and sensors, DC motor and an encoder + power supply etc...
2. board to communicate between pc and sensors, stepper motor + power supply etc...
Of coarse there and a lot more ways of doing this, im just outlining two that i think would be fairly easy for a person new into electronics.
The term "stamp", the first thing that pops into my head is the stamp dev board... I dont know if thats what your thinking?
For programming languages, i don't really have much experience with "on pc" languages so i cant help with that too much. But most of the standard usb interface boards will come with software to get you started whether it be a ready made program that you use or one where you code it yourself using their library of something...
k....I'm a little confused. let's say i take option #1....could you explain exactly what would be connected to what? (example: pc to board, board to motor etc)
and I don't understand the part about a power supply. Is it like a computer power supply? Do I need to buy a special power supply depending on what board I buy?
also, do you know if it is possible to program a board using C++?
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Quite simple really, the setup would basically be:
(PC) - (interface board) - (motors+sensors+power supply)
The power supply doesn't have to be anything special, it can just be a battery pack or a wall wart.
The supply will most likely plug into the interface board which will power the motors and electronics.
You probably could program the board in c++ but most pre-made boards will come with some kind of program readily made, chances are that you could make up a program in c++ but it will vary from board to board.
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Quite simple really, the setup would basically be:
(PC) - (interface board) - (motors+sensors+power supply)
The power supply doesn't have to be anything special, it can just be a battery pack or a wall wart.
The supply will most likely plug into the interface board which will power the motors and electronics.
You probably could program the board in c++ but most pre-made boards will come with some kind of program readily made, chances are that you could make up a program in c++ but it will vary from board to board.
Alright thx.
So if I'm looking for a board for this robot, what should I look for? Does processing power play a role in these kinds of motherboards? Are there certain slots that I need to make sure that the motherboard has?
Also, I can think of one significant problem: for this particular robot, the stepper motor needs to be mounted on top of the turntable (DC Servo), which will turn it over 180 degrees, so it can't connect to the motherboard using a normal wire....it would need some sort of device that would connect it to the mother board "through" the DC Servo (or around it), so that the angle it's at doesn't matter. (for example, if a wire was used, the Servo would twist the Stepper around and around until the wire was twisted around the robot). Do you know of anything that does that?
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One board that im thinking about right now is the phidgets board: http://www.phidgets.com/products.php?category=0 (http://www.phidgets.com/products.php?category=0) .
The only thing is that they are kinda pricey... But they have what your looking for.
A cheaper option that im thinking about is using an arduino as one, using the USB output to talk to a pc through hyperterminal or something along those lines, i think its been done before...
About the other problem, the motor will be mounted on top of another motor, so it will tangle wires?
I think i have an idea about what you mean... This is a tricky one, look around for a bit, someone else must've done it before, im thinking contact plates right now but that might get a bit tricky...
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One board that im thinking about right now is the phidgets board: http://www.phidgets.com/products.php?category=0 (http://www.phidgets.com/products.php?category=0) .
The only thing is that they are kinda pricey... But they have what your looking for.
A cheaper option that im thinking about is using an arduino as one, using the USB output to talk to a pc through hyperterminal or something along those lines, i think its been done before...
About the other problem, the motor will be mounted on top of another motor, so it will tangle wires?
I think i have an idea about what you mean... This is a tricky one, look around for a bit, someone else must've done it before, im thinking contact plates right now but that might get a bit tricky...
thx that helps a lot. I looked at those boards....are the motor wires supposed to get wired in to those green hole things? also....what supplies the power to those boards?
Yeah it says that they can be coded with C++. perfect.
thx for helping me out so much btw.
I'm surprised that the contact plate issue isn't more common...I'll look around and see what I find.
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thx that helps a lot. I looked at those boards....are the motor wires supposed to get wired in to those green hole things? also....what supplies the power to those boards?
Those green things are called terminal blocks and yes, you plug things into them such as:
Sensors, motors and the battery pack. So to answer the other question, you would use an external supply to power the board.
I'm surprised that the contact plate issue isn't more common...I'll look around and see what I find.
Yeah, im kinda surprised about that too, most people just use long wires...
So, are you looking at dc motors or the steppers?
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ok so the power supply goes into the green things.
For motors, I'm thinking two steppers now. i know that the angle measures need to be accurate and consistently the same, i think stepper motors would do that the best. \\
do you happen to know how many degrees one "step" is on a stepper motor?
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do you happen to know how many degrees one "step" is on a stepper motor?
Depends on the stepper motor ;)
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For stepper motors, I looked around and found this: http://www.anaheimautomation.com/products/stepper/stepper-motors.php?tID=75. (http://www.anaheimautomation.com/products/stepper/stepper-motors.php?tID=75.)
I was looking at the 17L0 model...do stepper motors usually cost that much? Also, would that have enough peak torque to turn with a sonar sensor and another stepper on top of it
on the page http://www.phidgets.com/products.php?category=0&product_id=1018, (http://www.phidgets.com/products.php?category=0&product_id=1018,) would that board be able to power two steppers and a sonar sensor (http://www.phidgets.com/products.php?category=2&product_id=1128 (http://www.phidgets.com/products.php?category=2&product_id=1128))?
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Those steppers are kinda pricey... I would look around a bit and see if you can get any cheaper ones.
Not sure if the torque would be sufficient but http://www.futurlec.com.au/StepperMotors.jsp (http://www.futurlec.com.au/StepperMotors.jsp)
on the page http://www.phidgets.com/products.php?category=0&product_id=1018, (http://www.phidgets.com/products.php?category=0&product_id=1018,) would that board be able to power two steppers and a sonar sensor (http://www.phidgets.com/products.php?category=2&product_id=1128 (http://www.phidgets.com/products.php?category=2&product_id=1128))?
Yup, it can control two steppers, but it is not likely it will be able to control it directly.
You will most likely need to have a relay/transistor in between them.
As for the sonar, it can take it, it has analogue inputs.
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Those steppers are kinda pricey... I would look around a bit and see if you can get any cheaper ones.
Not sure if the torque would be sufficient but http://www.futurlec.com.au/StepperMotors.jsp (http://www.futurlec.com.au/StepperMotors.jsp)
hmm...well if i'm reading those right, it sounds like their minimum turning angle is 7.5 degrees instead of .9 degrees. It would be nice if I could find stepper motors for $6.00 instead of $60.00 tho....i'll keep looking around.
Yup, it can control two steppers, but it is not likely it will be able to control it directly.
You will most likely need to have a relay/transistor in between them.
As for the sonar, it can take it, it has analogue inputs.
a transistor/relay....dang it.... is it that particular board that needs a relay, or all motherboards? do you mean relays like on this page: http://www.phidgets.com/products.php?category=9? (http://www.phidgets.com/products.php?category=9?) if so, which one should i use?
also, how do you connect them.....do they get power from the motherboard? do i connect them using the green things?
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Do not try to reinvent the wheel. A simple google search "usb stepper" yielded this:
http://www.trossenrobotics.com/phidgetstepper-unipolar-usb-4-motor-stepper-controller.aspx (http://www.trossenrobotics.com/phidgetstepper-unipolar-usb-4-motor-stepper-controller.aspx)
Instant PC to stepper motor control!