April 2008 Summary

Summary of work and posts for April 2008

Posted by Chris on April 30th, 2008 in General | No Comments


Holo Projector Servo Test

I’m definitely getting into the fun part of the project. I spent part of the evening trying to add a servo to the front holo projector. It was a little more tricky than I thought it was going to be. I’d seen photos and vaguely remember a setup on one of the tables at C4, but until tonight I didn’t understood the nuances of the angles and forces need to move something with a servo, so it was frustrating and fun at the same time.

Most people seem to use the same basic method to move pie panels, doors, holo projectors etc. And that’s to convert servo rotation into a linear movement using a push rod attached to the servo horn.

I’d bought some random mini servos from Tower Hobbies a while ago (Hi-Tec HS-55), and a push rod/linkage assembly from ebay. Problem was the servo was too small to fit the rod attachments. I managed to improvise and this is what I finally came up with

Please ignore the kinks in the rod, it really should be straight, but I’d tried to copy what I’d seen at C4 and got it totally wrong 😀

If I was to do this again I’d probably skip the pre-made assemble and make something in acrylic and parts from the local hardware store.

I also created a short video to summaries and demo the new setup.

As I explain in the video it’s not perfect, and I need to affix the servo more permantely to the dome rather than using velcro and I’m not entirely confident the linkage to the back of the HP will last very long.

The good news the Hi-Tec servo is definitely powerful enough to move the HP and will probably work for the pie panels as well.

I also need to decide if I’m going to add some code to my micro-controller to automate random movement.

See Also:

Posted by Chris on April 29th, 2008 in Dome, Electronics, Events, Legs | 14 Comments

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Mounting Dome Electronics

I was getting tired of my disorganized electronics in the dome, so I made this little holder that mounts everything cleanly and is easily removed.

It’s just a piece of acrylic bent into a U-shape with an extra L-shaped shelf glued in the middle.

The various electronic boards are velcro’d into place for easy removal and the whole thing attaches to one of the dome ring supports.

Top: Syren10 Speed Controller (Dome Periscope), 12V/24V DC/DC Power Converter
Middle: Power Distribution Board
Bottom: 12 Channel RF Receiver

I secure the wires that run up to the dome to make sure I don’t accidentally pull everything off when the dome is removed

Please ignore the 16 gauge wire as well, I was running short of something lighter but didn’t want to make a special trip to the store.

See also:

Posted by Chris on April 28th, 2008 in Dome, Electronics | 8 Comments

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Slip ring servo board brackets

I added some support brackets to the slip ring servo boards. Nothing fancy just a small piece of extruded aluminum with a few holes in it.

I made them slightly longer than the boards to allow extra holes for mount.

Posted by Chris on April 27th, 2008 in General | 4 Comments

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A look inside the failed Pittman gearbox

I replaced the failed Pittman dome motor last night, and thought I’d post some pictures of the failed gearbox.

The pen tip is pointing to the failed gear in the center of the picture. The teeth are almost stripped flat.

And this is the new motor opened up and how the gearbox should look. Again the gear in question is in the center of the shot. Notice the teeth!

I’m not confident that it will not fail again, and I may need to look at an alternative. I’m hoping the issue was my failed attempt to use batting tape to line the dome bearing to help with traction, but the gear may have been slowly failing with the constant harsh stop/starts on such a small gear. I know of at least one other builder that had a Pittman dome motor fail in the exact same spot.

Posted by Chris on April 26th, 2008 in Dome, Electronics | No Comments

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Slip Ring Servo Test

I finally got a chance to fully test out my slip ring last night with some servos.

I first had to finish soldering up my little boards that would handle signal routing and power.

Rather than try and explain in words and pictures how the setup works I made this short video to try and give a good overview and show the slip ring in action.

I still need to make little brackets to secure the D sockets to the boards, and decide the best place to locate them in Artoo.

See Also:

Posted by Chris on April 25th, 2008 in Body, Dome, Electronics | 2 Comments

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New R2 Event Banner

I’m busy getting ready for Makers Faire and printed off this vinyl banner yesterday for the booth at the event.

It’s approx. 36″ x 60″, and Artoo is almost full size. It’s based on graphic used at the last few SW Celebrations. Thanks Cory for giving me permission to use it.

New R2 Banner

I plan on making a stand out of PVC to mount it on.

And Gerard will have his tall C-4 banner there too.

Posted by Chris on April 24th, 2008 in General | No Comments

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More WonderCon Videos

Here’s a videos I just found on YouTube of our appearance at WonderCon this year.

Posted by Chris on April 23rd, 2008 in Events | No Comments

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