InMoov finger

Today, I decided to get on with putting together the InMoov 3d printed finger.  I wanted to see how good the 3d printing was and how the construction was done for one of the fingers, seeing as I've got to do all of them, I wanted to get to see how they were put together and how they can be controlled by a servo.

Well, there's the basics all laid out:

After a bit of digging around, I found some acetone (nail varnish remover to you & me!), why we'll need that will become clear shortly....

....as the 3d printed finger parts are ABS, you can use the acetone with a small brush to melt the parts together - there's the finger parts on the right melted together and with the blue joint material threaded through to hold it all together - works pretty well:

For now, time to attach to the base unit:

So, this was the original HobbyKing servo I was going to use.  Note those 2 extra circular discs were meant to be used, but they don't fit the servo, so I opted no to use them yet (that will change)

Now it was time to thread the tendons through the finger, I mis-used an LED to help push through the last part of the finger - hey, whatever works, right :-)

...and there we have it, 50% done...

 ..and there's the other 50% threaded through:

Now to hook up the servo to digital Pin3 of the Arduino (just easier and quicker to test with the Arduino)

 Quick bit of code:

 Verify and compiled:

 Downloaded:

....and there we go, we can now flip the finger when we need to.  I've left off the end of the finger-tip for a good reason.  You'll see the tendons are tied off there and you then melt the finger tip over the top, but it makes it permanent...and, well, I don't want to do that just yet.

Of course there are challenges.  Wouldn't be fun if there wasn't some.

Here's a quick video:

As you can see, it kinda works, but I need a better pull/Robring mechanism (basically a dished outer edge to the white plastic circle on the servo, so that the tendon can move further back) - with a better mechanism the finger will be able to pull back straighter than it does right now.

Hey, it's all learning....small steps.  Now, time to get those .stl files over to a 3d printer and get a whole hand and arm printed up ready for the next phase.  Until then, I'll switch back to the code side of things and see if I can get the Kinect hooked up for vision and get it to react by moving servos etc...