Solar energy for cheaps

The robot will need all the power it can get, and solar panels has been a part of the plan from the start.

However, two problems with solar power has been evident that I have not been able to figure out:

• They are prohibitively expensive!
• They are fragile

Actually the last point may be a solution to both problems in a wired way, because I just discovered that solar cell manufacturers actually sell left over broken cells cheaply by weight or watt. Since they are already broken they will be less likely to break (smaller pieces) and fitting them into a lattice or grid will provide a flexible layout with the redundancy necessary to sustain power after loosing a single cell.


The plan is thus to buy some broken panels, cut them roughly to size and stitch them together in a grid with redundant connections.

How are lubricants classified & graded?

After reading the manula of the emco F1P CNC Mill and learning that it recommends 4 different lubricants for different parts of the machine I have attained a genuine interest in learning more about lubricants, so I have now asked a question on the chemistry stack site, asking exactly how they are classified and graded.

You can find it here.

Unboxing (unbagging)? of IOIO OTG

This is my second IOIO OTG. The first one was DOA.

UPDATE: DO NOT ORDER THESE, they were all DOA. Recommended supplier of IOIO is sparkfunn and seeedstudio.

STAY AWAY FROM GEEETECH IOIO OTG

This time I ordered x2 to make sure I didn't get a bad one again (returns takes ridiculously long time sometimes).


It is designed by this guy, manufactured by geeetech and was delivered by dx.com.

It promises to give you access to hardware comfortably from your Java IDE, Normally an idea I don't like but in the name of efficiency I decided to go this route instead of working my way through all the low level C/C++/AVR stuff to get some motors and servos moving.

The idea is to use it for prototyping and when it gets serious I will port my efforts to more robust platforms.

IOIO OTG with bluetooth adpater in the bag

IOIO OTG with bluetooth adapter unbagged

A study of spiders

The decision of copying spiders in the physical design of the robot has spawned some extra focus to the project.

Here are some you-tube videos showing spiders moving in slow motion:

 

And here a study of the degrees of freedom found in the legs of a spider, summarized elegantly in the two shamelessly borrowed figures below:

Range of freedom in XZ plane (Z is up)

Range of freedom in XY plane (ground)

Cobalt blue tarantula

Lately I have pondered (in-between the bouts my extremely demanding and satisfying job) about how to model the physical layout of the robot.

I have proclaimed it to be a hexapod from the start. This idea seemed like the most logical at the time. 4 is too few and 8 is too many. Having an odd number of limbs leeds to more complex gaits. Also, keeping the number of movable parts per limb low would reduce the cost and complexity of each limb.

However now I am not so sure any more. I personally like spiders better than insects and spiders have 8 legs. Also, the number of moving parts per limb in a spider (and in insects too for that matter) is much higher than 3. Evolution is the best mechanism to achieve optimization there is, and it has been working for over 4 billion years to perfect the spiders we see today. It follows thusly that one would be unnecessarily stubborn/proud not to at least observe, analyse and learn from the way spiders are.

Anatomy of a spider, for study before deciding on the anatomy of a robot.

What's in a spider anyways?

So I decided  to go all in, and find the perfect spider species to use as a template for the design of the robot. I ended up with the cobalt blue tarantula as the best  candidate for the following reasons:

• It is strikingly beautiful both in color and proportions. I firmly believe that aesthetics play a bigger role in design than merely pleasing one's eye.
• It is not too specialized. Many spiders have specialized into niche markets that make them unfit as a model to a "general purpose" robot. It is a solitary hunter and so is my robot.
• It has an well balanced anatomy that would be relatively easy to replicate.
• It has a temper similar to that which I want to give the robot (shy but aggressive).