August 2007 Summary

Another slow month, but at least I got some work done

Posted by Chris on August 31st, 2007 in General, Update | No Comments


In the Blue Corner…Weighing in at 155lb…RrrrrTwooo-DeeeTwoooo

Chris' R2-D2

At the R2-CCA event this last weekend I got to weigh my little buddy. The trick is to use a single bathroom scale and move it from foot to foot and to add up the combined weight. The other feet need to be kept level with the scale using wood blocks, otherwise the result will be invalid.

I was surprised that he’s already over 150lb. The dome alone is 17lb and that’s without the periscope. The problem is the two 12v batteries and dome mounting plate – and of course all those alu Holo projectors, radar eye and logic surrounds.

I can easily see him hitting 200+lb once I add the skins, body detail and extras like computer interface arms and other motors/servos to trick him out.

In contrast Ed’s finished droid was closer to 110lb and nobody else at the event had any problems pulling their dome on and off with one hand except me!

Posted by Chris on August 14th, 2007 in General | 2 Comments


R2 Loading Ramp

One of the challenges of owning a droid is transport. Not everyone has a Sandcrawler handy or can afford a fancy trailer, and most cars are too small.

When I went down to C4 in LA I removed his legs to fit him in the front seat of my Beetle, but I knew this was not a long term option and I needed to come up with a better solution.

Luckily we have an old 1994 Dodge Caravan that we use for hauling stuff around. It’s not in great shape and the wife has wanted to get rid of it for years, but I’ve resisted and it turns out the van is perfect for carrying R2 once the bench seats are removed.

I was tempted to build a winch system similar to Mike Senna’s, but my droid is much heavier and would probably require a welded frame. The side door of the van is very low to the ground and I decided to try a ramp system first and have R2 load/drive himself in instead. I bought an aluminum ATV ramp at Pep Boys and cut some plywood for the top.

Here’s a short video of us loading my R2 at R2-CCA this last weekend. I still need to get some thick carpet or maybe even plywood for the floor of the van to stop his feet sticking in some grooves in the floor of the van, but overall the loading is very simple.

It may look like I’m pushing R2 in the video, but he’s driving up the ramp under his own power.

Posted by Chris on August 13th, 2007 in General | 2 Comments

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R2-CCA 2007 v2

Big thank you to Ed and his family for hosting today’s R2-CCA gathering in Elk Grove.

Weather was perfect and the company excellent as usual.

Here’s some photos from the event [more here]

Ryan, Chris, Gerrard and Ed the host - and of course their R2's

We even got some building/fixing in between food and tech talk.

Posted by Chris on August 11th, 2007 in Events | No Comments


Hiding Drive Wires

Here’s another retroactive post about something I worked on a few months ago.

One of the challenges is passing the drive wires that goes from the ankle into the foot shell. Some people use the totally hidden/invisible method where slots are cut in the side of the ankle and foot shell very close to the bolt. Here’s an example of Wayne O’s setup using this method.

Space is tight and things have to be perfectly aligned or you run the risk of chopping the wires when the ankle pivots. It’s also virtually impossible to add grommets so over time my worry is that the wire may wear. edit 9/7/07 – Wayne just informed me that his setup above has been working fine for over a year and half without any problems or wear and tear.

I was on a time crunch and not sure if I was up to marking and cutting such precise slots, so I opted for the more conventional method of drilling holes in the foot shell just behind the ankle and corresponding hole in bottom of the ankle.

My wires are pretty think and by my calculation I needed a chunky grommet, but I couldn’t find anything suitable so had to improvise. Instead I used a short length of opaque tubing which passes through from the ankle into the leg. Not only does it protecting the wires it also hide them.

This is the inside of the Ankle

And the Foot Shell

Tube passing from the ankle into the foot shell

I also used the same hose in the top of the legs/shoulder to protect the wire as it passes into the body.

Posted by Chris on August 6th, 2007 in Electronics, Feet, Legs | 2 Comments

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Quick Tip – Masking Parts

Here’s a quick tip when painting those hard to mask parts like the groves on the Booster Covers and inside surfaces of Power Couplers.

I wanted to use rubber latex to mask of my parts but for the life of me I couldn’t find any in local stores. Short of time and rushing for C4 I came up with an alternative – Elmers Rubber Cement – which is made from mostly Latex. It’s readily available at most craft stores. It’s goes on clear so somewhat hard to apply as it’s hard to see where you’ve already covered.

If you can get Liquid Latex then I’d recommend using it – but in a pinch the Rubber Cement worked for me.

Masking Hard to Paint Parts with Rubber Cement

Posted by Chris on August 5th, 2007 in Finish/Paint | 2 Comments

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Mist / Fire Extinguisher Test

Well I’m back working on R2. It’s been a while since I’ve done anything on him and I’ve still got a long list of big to-do’s. Sadly, instead of working on the small things I’ve been avoiding everything.

Inspired by reading Victors success with the Mist/Fire Extinguisher effect this week I decided I’d give it a go this weekend, hoping it would kick start me going back to work on more difficult things like the skins.

The mist is created by an inverted can of compress air normally used to dust PC’s and office equipment. When it’s inverted rather than spray air, a watery/icy mist comes out.

I decided to put the air cannister and output in the dome instead of the body. I really liked the idea of popping open a dome hatch/side panel and having something come out, and I thought this would be perfect.

I’d already bought a cheap solenoid which was part of a trunk release kit I found on eBay. I had looked locally, but eBay seemed to be cheaper. Wiring it in was a snap and it’s only a few wires. It’s triggered with a spare channel on my RF remote.

I cut a 1 1/2″ acrylic strip and bent it into an L shape. I bolted it to the Dome Mounting Ring and then used clamps to hold the cannister and solenoid to it.

I drilled a small hole in the trigger of the air cannister and connected it to the solenoid with a bend paper clip.

Here’s a rough diagram of how it’s wired

Space in the dome is tight and I’m sure I’ll need to move things around or lower/angle the cannister more to accommodate the periscope lift mech.

Here a short movie clip of the first test with the dome off

Then with the dome on

I still need to add a hinge to the hatch and power it with a servo. I did tinker a bit with the Robart hinges but decided to leave this for tomorrow.

Posted by Chris on August 4th, 2007 in Dome, Electronics | 1 Comment

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