Monday, April 5, 2010

R2 upgrades continue: Frame, computer interface arm and installing the ServoCenter card

Work continues!

It took a while but I have the computer interface arm working so that it extends and retracts.  I used an aluminum servo bracket screwed into the resin piece, then attached a servo and extra long metal horn.

There was a fair amount of trial and error with the r/c aircraft pushrod, the alignment and so forth.  Here is a YouTube video of the setup in action.

It worked but was a tad slow.  I decided to consult with my friend Warren at King's Mountain R/C in Orrington.  Warren suggested a more powerful servo, so I upgraded from a 72 ounce (torque) model to a 142 ounce model.  

One big difference is that this servo has a metal top ...

While I have the interface arm working, I am going to have to put this mini project aside for now.  The piece is too heavy for the pan/tilt servo system I had hoped to use.  I'll have to refine my ideas some more and try again with a motor tipping the device in and out of the body.

The next thing on the To Do list was shoring up the frame.  I had to remove two frame rods to allow for the tall door to open and another for the two small doors to open/close too.  

What I was able to do was move the frame rod back about an inch.  This stabilizes the load on the frame and is far enough out of the way for the door hinges to open and close without obstruction.

Next up was mounting the ServoCenter USB to Servo controller card.  This card connects to R2's onboard computer via USB and allows my software to communicate directly with the servos.   Once I found a good spot, I wired it into the RigRunner with the proper fusing and tested it out.  

After I took the photo, I added some .75 inch diameter holes below the card.  The servo cables will feed in thru there into the card.   

One of the final things I tackled today was the backplate that goes behind the utility arms.  For the longest time I have simply taped it into place since, well, that worked fine!  I lined up where the plate should bolt into the frame and marked it off....

If you look real close, you see two blue dots on the vertical piece.  Tomorrow I need to dismantle that assembly and make the mounting holes.  A fairly quick drill, tap and bolt into place task.  

What's next?  

*  Repairing and re-mounting the blue surround plate that goes around the center vents.  It got dented a while back and popped loose.

*  Center vents need to be re-aligned and locked into position

*  Install the SoftPot potentiometer.  This device will input data into the ServoCenter card and allow the computer to know where R2's head is pointed.

That's all for this update.