Early this morning I snapped a few pictures of my scout, Gordo. He’s running a BrainStem GP 1.0 with a Devantech SD21 servo controller, however I have an Atom Basic Pro/BotBoard 2/SSC-32 on the way for a future conversion. All the software is in VB.NET, including a custom pose designer and sequencer I hacked together in the last week. He’s almost walking, too! I designed the gait from scratch with a lot of testing/tripping/falling.
He’s getting an XBee wireless module (isn’t mounted yet, but I have hooked it up and it tests fine), 6-cell converted to dual leg-mounded 5 cells in parallel, wireless cam mounted to the pan/tilt, rubber foot grips, and a few other goodies I can’t think of right now.
It looks like the ankle bracket is placed too far back on the foot plate. The ankle bend, (not rotate) is almost hanging off the end of the foot plate. Moving it forward will make it a bit more centered.
I ordered the proper servo horns so it’s all coming apart this weekend anyways. I hope those new horns will be easier to get on and off than the stock hitec horns. That’s how I got that big scratch on the left ankle
Looks great, Jeff. He’s standing straighter than mine does and looks fantastic. I’d love to see a video of the gait if you get a chance.
I tried rubber grommets in the feet for mine to stop him sliding around so much (the 3/8" x 1/16" x 5/8" x 7/8" x 5/16" rubber grommets from Cable Organizer fit perfectly in the large holes in the feet). It didn’t work as well as I’d hoped, as sticky feet + clumsy shuffle isn’t a happy combination. I’ll try them again when I get the walk sorted.
Thanks Matt! My gait is coming along well but he isn’t walking yet - the pose where he needs to plant the extended foot, shift weight, and make the upright transition isn’t quite right. I’m hoping that once I get that sorted he’ll be able to walk with or without the rubber feet. I really like the grommet idea though, much more elegant than those square sticky things I ordered.
Oh, and what to say about the BrainStem… it’s okay I suppose but it isn’t the right tool for the job, at least not for what I hope to do. The thing that bugs me is that it only has room for 11x 1k TEA programs, which ain’t a whole lot. I planned on storing raw pose data in some of the slots and have another TEA program accessing the data through direct memory access commands, but even still I don’t see how I’m going to hack in telemetry and a 2 axis gyro balancing system in just 1k of code. I will say that the I2C bus is pretty darn cool though. As far as the SD21 servo controller, it does provide reasonably fluid motion however it’s nowhere near as powerful as a real hardware sequencer like the SSC-32. I can’t wait to get my hands on one of those. Another thing about the SD21 I found is that if you set to many registers too quickly it just ignores them. Even with a 115kbps serial link and 100kbps I2C I can still only send about 50 commands/second to the SD21 reliably.
Fred I agree 100%, I’m thinking about using some sort of flexible steel conduit for wire management. The trick is finding some that’s small diameter and not too stiff. :-/
It’s appropriately titled “bought the wrong servo I guess…” since he started out with servos that were too weak and then went for broke and bought a set of 5990TGs…
Thanks! Yup those are all 5980’s except the pan/tilt kit, and yes you do have to keep a close eye on the case temp especially when designing 1 leg poses where the entire weight is working against one or two servos. I keep a fan on him while I’m designing the poses, an IR thermometer nearby, and take routine breaks. I actually have a really stupid reason for not going with the 5990TG’s - I didn’t like the way the case looked. I’m hoping temps won’t be as big of a deal when I drop down to 6V but I’ll let you know.
I’d love to see some pics of MrMikey’s scout and would like to know if he ever got it walking. I think my biggest problem is where I mounted the battery - having that much weight that high makes him prone to falling over when shifting between feet in the middle of the walk. The dual leg mounted design should fix that.
Thanks! The basecoat is called copper brilliance, made by Krylon. Just spray all the parts in several light coats, giving about 15-20 minutes between each. For the weathering I used a Badger 150 airbrush with a medium tip and Createx airbrush paints. I started with a transparent light brown, darkened to taste with opaque and transparent black, then watered it down approx 2:1. I had to adjust the final mix as I added a little too much water the first time. The effect you are going for is a dusting, the paint should stick in distinct spots and not puddle together. If it starts to puddle then you are using too much water. Once the mix is adjusted simply apply the paint roughly 10-12 inches from the parts, darkening the outer edges and leaving the center parts brighter. If you are trying this on your own you may also want to give them a final coat with a clear matte finish sealant as I’ve found the airbrushed paint to be easilly scratched (although the Krylon for the most part holds up great). If you paint your bot I’d love to see the results!
Thanks!
