I’m working on the frame again this weekend.

This week I bought more aluminum and got some more parts cut out and ready for assembly, I also lucked out and got some spare parts from Jerry. I still need to cut, drill and machine more but I’m making progress. With a bit of luck I’ll get the vertical rods drilled and taped this weekend and I can start putting the frame together early next week.

One of the challenges on working with the official club spec drawings is that they’re in inches, and being from the UK and brought up on the decimal system (mm, cm etc) it’s hard to get my brain around it, especially when it comes to inches quotes in decimal – confused? I know I am. How do you measure 3.8750 inches with a ruler that only has fractions marked on it? Here’s a handy chart that help me along.

Darren Murrer has been working on some new laser cut domes for the group, and today he’s at the machine shop getting them laser cut.

He setup a webcam for us all to watch live, and I grabbed a few stills and put them together into this animation.

Enjoy.

I got to test a few of the satellite motors tonight for the first time. There’s an enormous amount of torque in them, but before the motor will turn you have to release the break using the white and black/white wire connected to a 12v or 24v battery. You should hear a snap or a click when I releases.

The motor is an integral part of many peoples 2-3-2 leg design, or even straight 3 leg designs, mostly due to the very popular JAG frame. I’ve yet to see anyone use them successfully in a 2-3-2 astromech, and heard some horror stories of people who have tried and failed. I’m hoping we’re going to see some working 2-3-2 implementations at C4 that overcome the shortcoming of the motors. But I’m not going to hold my breath.

I’m still not sure I’m going to use them right away, if at all. The major drawback with the motors is that on a heavy droid the gear teeth can sheer under stress. It’s not so much from stationary rotation of the legs/body, but when driving the droid around. The only thing hold the leg in that position is the small number of teeth that are engaged in the gearbox, and the inevitable happens.

Robert Ross has a prototype design for an external mechanical lock mechanism that will removes the stress on the gearbox. I’m trying to decide if I want to fabricate something similar or wait and see what happens after C4.

Another step closer today.

I was fortunate to pick up some shoulder to body hubs, and this is the last complex machined part that I need. I owe a lot of people drinks at C4 for helping me find stuff.
Frame build is well underway, and I’m now realizing how heavy this thing is going to be when done. People keep on saying 200-250lb for an all aluminum droid, but until you hold a stack of the parts bolted together it’s hard to imagine how heavy that really is. Time to start working about transport and storage in our two story house.

Tired of waiting for an aluminum frame run I decide to give it a shot myself. I doubt I’ll get it done for C4, but I’m going to give it a shot.

I have a friend who lent me his time and shop, and this is what we came up with over the weekend.

It’s the shoulder/leg mount, which allows the leg to rotate the 38 degrees from 2 legs to 3 legs.

I figured it was probably the hardest part to make out of the entire frame, so if I couldn’t get his made then there was no point in making anything else.

I think it came out pretty well, but took a lot longer than I thought it would.

Here’s a quick diagram of the frame and it’s various components –

Next up the frame rings.

Big thanks to Jon for the use of his shop and his time showing me the ropes, and to Jerry for allowing me to use his plans.

A couple of people have written and asked how I configured the SyRen10 Speed Controller and how I connected it to Vex Micro controller, so I thought it best to document it here for future reference.

Setup and wiring was very easy, and I simply went through the online SyRen setup wizard and picked logical answers.

As you can see all but dip switch one are set to ON.

And here’s how the controller is connected to the Vex

There’s only 4 other wires needed, 2 to the battery (V+/-) and 2 to the motor (M+/M-)

I did some further testing of the periscope lift mech tonite. Got it partially installed in the dome. Just placed inside on the dome plate to see how much room I had to play with all around.

I was hoping I’d have enough space in there to add a small servo to rotate the periscope as the mech only raises and lowers – But it really doesn’t look like I’ll have the room.
I also need to widen the hole in the dome as the periscope housing touches in several spots.

I think things will improve once I get the housing glued together and more square, but this was a good test to make sure I’m on the right track.

I’m going to sleep on it tonite and try and figure how I can get the thing to rotate – even if it’s just 90 degrees.

As it lowers you can see that it touches the dome.

Big milestone for me tonight. I finally got around to wiring up my dome periscope lift mech to a speed controller and my VexLabs RC setup.

This is my first time wiring up anything like this, so I was a bit apprehensive. The good news is I didn’t pop anything and it worked first time.

I was really surprised on how fast the little motor spun the mech up and down. So fast that the threaded rod squeals a bit. I may have to program in limits on the controller to cap the max speed.

Here’s a quick photo of the test setup and a video

For the test I used a SyRen10 Speed Controller.