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.
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|Comments Off on A look inside the failed Pittman gearbox
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.
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.
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|Comments Off on New R2 Event Banner
