The following is a breadboard layout of my basic requirements. I am choosing to use three pins on the arduino, to power 4 DC toy motors and 2 stepper motors.
I have built a circuit that combines the use of 3 H-Bridge controllers to manage 5 DC toy motors in a robot arm from one source (luckylarry) and added in the shift controllers from another source (Dave Auld). I then added an additional H-Bridge to give me enough motor control.
x2 - Connects arduino pin 2 with the data pin on shift controller 1
x3 - Connect to the other x3 on controller 2, and arduino pin 3
x4 - Connect to the other x4 on controller 2, and arduino pin 3, I have also added a 560 ohm resister between this part of the circuit and GND
A - Connects the output on shift controller 1 to the data in on shift controller 2.
B to Q connect shift controllers to the input pins on the motor controllers.
Basically assuming that the two example circuits work, then my circuit should also work.
But if there are any other tweaks that could be added to make the circuit more reliable then I'd appreciate the advice.
3 x Arduino pins connect shift controllers 1 and 2.
Shift controllers connect to 4 H-Bridge Motor Drivers and also to GND through a 560 ohm resister (as per Dave Auld's circuit diagram linked earlier)
Motor Driver 1 connects to two small toy DC motors
Motor Driver 2 connects to two small toy DC motors
Motor Driver 3 connects to a 2 phase 0.90 degree unipolar/bipolar stepper motor
Motor Driver 4 connects to a 2 phase 18 degree unipolar/bipolar stepper motor
Toy DC motors control the basic movements of a maplin robot arm.
As per Christian Liljedahl's 'Simple Rotary Encoder with Arduino' guide
I'd want to add a 10-20k resister to one of the inputs to enable me to get a very basic understanding of how far the motors have moved.
The 0.90 degree stepper motor should operate in half (or even quarter) step mode, and controls the slow movement of the laser scanner
The 18 degree stepper motor should operate in full step mode, and rotates a turntable 360 degrees in 10 stages of 36 degrees
No connections are required for the laser, which has its own housing, circuit and battery.
The robot arm itself, can hold 4x D Cell batteries to power motors, although I'd ideally want to power via the Arduino's USB connection or a direct connection to the mains.
I also noticed that in Larry's robot arm hack, the motor controllers do not have connections to their enable pins. I'm not sure if that needs to be corrected
4 x MINIATURE DC MOTOR
Based on searching through Farnell, the motor is the same dimensions as their two cheapest motors, and smaller than the cheapest '3.0V to X' motors. The motors themselves contain no marking to help identify the exact specs.
If you have, then you would notice something really quickly: The motor gearbox housings form the structure of the robot arm; they are integral to the design.
Some of the steppers you propose to use are larger than the gearboxes housing the motors on the arm itself (the arm isn't that big). Heck, the shafts on some of the steppers are larger than some of the gears in the gearbox!
You already say you don't have an understanding of electronics; this project is -not- a beginners project. Nobody has yet even managed to implement position feedback on this arm using the motors as-is (a requirement for the system you propose). You may be on a route to frustration.
Lastly - what is this "scanner" system supposed to do? Is using a multi-degree-of-freedom robot arm the best solution? If it is, and precision is needed, you are likely to find it better to purpose build the robot arm from scratch, and not try to convert something like this toy. If you must use something off-the-shelf, a commercial robot arm (while insanely expensive, even used) is going to be the better solution.
You need to, however, learn the basics of electronics, robotics, motor-control, feedback theory, etc - before attempting something this advanced. Otherwise you are going end up throwing a bunch of money and time at a project that is only going to end up frustrating you and your bank account...
The scanner is using David Laserscanner software and calibration panels
I have the robot arm, and am keeping all motors in their housing except one, which will do the scan itself, and sit in a custom housing that replaces the gripper.
The other stepper motor is for a seperate turntable.
Mechanics, hardware modification and programming are not a problem, just perfection of the the circuit. I dont require huge amounts of info from the 4 basic motors, they are literally just to get close to the right position start position for the scanner from location readings previously taken.
I have already spent around £1000 on a cupcake cnc which can make my custom housing, £30 on the arm, and £350 on the laser scanner.
I now need to buy an Arduino, a large breadboard, the two motors and the circuit components. Buying an arduino and 4 motor sheilds is the alternative but with significantly more expense
I bought this arm a while ago, also inspired by Larry's blog. But to reiterate what cr0sh said - serious position control with the arm in its standard, out-of-the-box configuration is almost impossible. In fact, I found out this year that my university bought this arm to see if they could do anything with w/regards to position control, and a few projects were done on it. The conclusion? The gear slip makes it almost impossible. If it is at all possible, it will require some serious, serious control techniques.
And you said it only has to be able to roughly (you should make sure you know your own definition of 'get close', by the way) reproduce locations... well you'll also have to find a way to make your control solution not let errors from gear slip become cumulative.
This is really not a beginners project.
And something I don't believe anyone's pointed out yet - when you were asked for a 'schematic', I think they were talking about a circuit diagram. Your breadboard layout is a kind of... abstract circuit diagram, I suppose, but as Grumpy_Mike pointed out, nobody's going to sit and decode that into a proper cct diagram for you, you need to do it yourself.
You've obviously invested a lot already, so good luck with it!
IMO things like Fritzing are probably good for class rooms etc, the trouble with them is that anyone who knows about electronics will run a mile if you show one of those "realistic" drawings. They are unintelligable to someone used to working with proper schematics, and those are the people you need to help with a project like this.
I know it will be difficult to learn a proper schematic capture program but if you want much help from "experts" I think you should bite the bullet, you'll have to one day anyway. It WILL be frustrating I can garantee it, but schematics are the language we talk in electronics.
Graynomad, you have a point. But the issue is that 01i Is obviously not familiar with this kind of stuff, and if he wants a circuit diagram quick and easy for us to see then fritzing automatically creates one from your breadboard design.