(video links at bottom!!!)
Hello again fellow Geeks and Geekets!!
while I am waiting for my robotrebels.org registration to come through I will have to post this here because I am too excited to show off this new project of mine.
I have been designing it for about two weeks then started printing a week ago. Over this weekend I soldered and installed all the motors and sensors, ran the cables, hotglued some of the sensor parts, tweaked some of my previous code to work with 6 DOF.
On sunday I was busily getting it to a stage of being able to run some initial tests. It is very similar in design to my last two robots. I re-used a lot of my own cog designs from previous builds but have added a couple of very nifty mechanisms to get position feedback out of the wrist and turntable. Unbelievably the turntable was one of the most difficult bits to design.
It was completely designed on a free version of Sketchup I downloaded ages ago. It uses the standard arduino IDE at present.It's basically a smaller version of 'the monster' which I haven't finished yet. It is entirely 3D printed and I am just using the little hobby geared motors that are very common here. Then using 10K potentiometers for the position feedback. I am using an arduino mega2560 for the control. I am using the L298 motor driver break out boards, as I bought a load from ebay a while back. At the moment it is just playing back positions I have taught it. However very soon I will be printing a little mini arm (with just encoders in) which will be used for teleoperation, so that I can control it remotely. Potentially this could be done through a phone app so I am going to do some reading on how to interface bluetooth to arduino devices, It can't be that difficult can it?
I am also hoping to add in a laser I have lying around, because, well, why wouldn't you?
The idea with this one is to make something that has much of the functionality of more advanced arms, but for the cost of a toy. I've long since wondered why OWI didn't ever add position feedback to their arm. It is so simple to do. Well as you can see this arm is not designed to be as accurate as some of the better ones, but I think I can make this for around £25 so that more than makes up for the lack of accuracy. I will add some more details and photos as I think of them. I need to buy a powerpack for it because I am using two 9 volt batteries and they drain after almost a minute or so. I will pop into maplins tomorrow and get a powerpack so I can do much better videos of it picking things up and copying my movements. I did have it picking a small box earlier but I didn't film it and the batteries are totally dead. More tomorrow!
I made lots of mistakes during the design process, the arm is supposed to be able to fold up almost flat when the elbow is fully contracted but I put the position sensors right in the way of the joint for some reason (doh!) so I will be revising that soon and also making the upper arm (femur) a bit thinner as it doesn't need to be so wide. I also need to make the grippers slightly bigger and give them rubber pads to grip onto objects. Well, let me know what you guys think. I am pondering whether to get all the files together and create some youtube videos on how to construct it. I am going to do some testing first and see just how accurate I can make it.
Let me know if you guys have any suggestions!!!!
VIDEOS:
