My Robotic Arm

I created this project as a EPQ(Extended Project), for my A Levels. Below is the documentation of the project as the same time you will learn how I created it. Thanks and I hope you enjoy it.

My extended project was to create an Artificial Intelligence robot claw, to the stage where it can move, grab and be controlled by an application over Bluetooth.

I believe that it was a relevant and interesting project because it allowed me to use most of my creativity and my interest in electronics and programming; also, it allowed me to learn new things, such as creating an app, how microchips work, and also a new programming language C++. So in the end I learned a vast of amount of information, which I believe was good for extended projects because there was so much potential for progression and planning to reach the goal of the project.

The goal of the project was to create an Artificial Intelligence robot claw.

So at the beginning I went about this in three stages

.• Planning

• Research

• Development/ testing

The planning stage was mainly looking at what I will be doing and then how much time I will be spending on the other stages to see if I was going to finish the robot on time.

Research was split in several parts.

• Learning C++

• how the Arduino works with h-bridges or a shield

• How to build an app

• How to create a PCB from scratch

Step 1: Step 1 Building the Robotic Arm

I started by assembling a bought robotic arm, then got rid of the circuit board that came with it to insert my own, which would be more efficient as then I could control it with a wireless adapter and not via the cable that came with the original circuit board.

Step 2: Step 2: Programing the Arduino

The next step was to control the robot with an arduino. I used breadboards to make prototypes, for then I could see that everything was working togethere.

The first step was to connect the Arduino to breadboards, which then would be connected to the motors of the robot.

As well of just connecting the wires I then had to program the Arduino for then I could send out the signals through the pins, allowing the h-bridge to set the each motor wire to high or low.

The code can be found on my blog; http://myroboticprojects.blogspot.co.uk/2015/09/my-arduino-code.html#more

Step 3: Step 3 Creating the App

Once I had the code working with the Arduino and controlling the robot, I moved on to creating an app and installing the Bluetooth module to the Arduino.

To create the app I used app inventor which is simple to use. I did some of their tutorials at first and once I understood how all the components work, I made my own app.

What my app had to do was send the same signals that my computer did when it was connected to the Arduino, For then the arduino could respond the same way.

Once my app worked, I had to connect the Bluetooth module to the Arduino that was simple as it was four wires involved, Ground, 5V, and two signal wire. Once everything was connected I had to test it.

Step 4: Step 4 Putting It All on a New Board

Once all of that was working, I made a custom circuit board; however it was not as efficient as I wanted, so with my supervisors we decided to use a motor shield instead. The disadvantage of using the motor shield was that it could only hold up to 4 motors and I needed to be able to control up to 6 motors.

So I started by re-writing the code for the Arduino and made sure that the shield worked with four of the motors. Once it did that’s where I had to decide. I had a choice of two options.

1. I hacked the Arduino board for then I can accept another shield with it in parallel but that meant understanding how a 74HCT595 latch work, and re-writing the code for the microcontroller chip.

2. Modify the motor shield for then I can add a custom circuit board to it.

After some thought and research, I found that I would be easier to just add my own custom board to it. So I had to make some new schematics, as my previous board was two big. So I used the same circuitry as my previous board but made it smaller. To do so I had to hand wire each components together.

Step 5: Step 5 Completing the Robot

Once I had the Arduino shield working with the circuit that I made I had to put everything together. To start off with I laser cut a base to put on the robot for then it can hold everything.

I then neatly tucked all of the wires into the robot and then made them come out just behind the Arduino. I then hot glued the Arduino and my circuit board to the laser cut base. I also added a switch to the battery pack for then I can turn on and off the circuitry. I tried and tuck in as much wire for then it had an appealing look to the final design.

For mor information on the EPQ itself check out my blog on it at; http://myroboticprojects.blogspot.co.uk/

Thanks for reading my first Instructables

Comments

[Alvenchipmunk]

What C++ compiler did you use and was it free? Did you use the C++ on the Arduino?

[AymericB]

I used the software form the Arduino website ; https://www.arduino.cc/en/Main/Software

Yes it's a free software, and yes I did use C++ on the arduino

[IAmBruce]

Who makes that arm?

What was your criteria for picking it over other available arms?

Would you still choose the same arm next time around or would you choose a different one (and why)?

[AymericB]

I choose that arm because it was one of the cheapist that I could find because I was on a tight budget, I had I had to redo it I would prefer to build my own arm form scratch, but it depends on the budget of cource

[AlyssonR2]

It is an excellent product for the price, and allows for all kinds of modifications (I put a cheap USB webcam over the hand of one that gives a view of the claw - and challenged some students to retrieve their reward (mini cup-cakes) just using the arm and the attached camera.

I have seen one used with a RC truck chassis to produce a scutter (that is just, plain scary).

I have also seen one with a modified interface that was controlled using a game station hand controller (PS-2, I think).

It is worth replacing the USB board with a simple motor break-out if you want to experiment - and then you can still connect the USB board (if still required) using a ribbon cable.

If you replace the batteries with a power adaptor, you do need to either put some weight in the box, or bolt the base to something solid.

[AlyssonR2]

This arm is available in the UK from Maplin.

http://www.maplin.co.uk/p/usb-controlled-robotic-a...

... and right now, it's on a big discount.

[8bitbeliever]

http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_2095023_-1

[8bitbeliever]

You can purchase that arm at jameco.com

[AlyssonR2]

A rather nice project, bringing wireless control to the OWI robotic arm.

One of the problems with the OWI arm is the lack of position and rate of motion sensing - which leads to poor position reproducibility and the awful ratchetting noise of the motors reaching the end of travel.

There are a couple of hacks for optical interruptors in the motor gearbox housings, but they lack end-position detection.

I agree with arkhipenko about the speed of response with this arm. In my opinion, you need to appy braking to the motors in order to reduce the overrun that they are prone to - either short out the motor windings when you want it to stop (NOT the power lines!) or pulse the motor with a reverse voltage to stop it dead (you need to provide extra protection to the drive circuit if you do this).

I would be interested to see an extended project from you, based on this project.

[arkhipenko]

Pretty cool project. How about using your phones accelerometer to control the arm?

Did you find the mechanics of the arm too slow? I could not make it follow the commands quickly enough to have a sense being connected to it. There is always a delay while mechanics are catching up...

Have a look at my version, just as a source of some other approaches ideas around controlling the arm, coding, etc.

https://www.instructables.com/id/Wave-your-hand-to-control-OWI-Robotic-Arm-no-strin/

[Bongmaster]

got the same arm, i am planning on putting some form of position feedback sensors on the joints so it can be controlled fully. most probably potentiomiters

[AymericB]

I was thinking of doing similar, also adding voice control. but I just ran out of time, If I had to do it again I would definatlly think about that

[DIY Hacks and How Tos]

Sweet robot arm.

[AymericB]

Thanks