Over the Christmas holidays I made a number of revisions (6-7) of a round robot base from high-quality, 9-layer solid wood core finish-grade plywood (the best plywood I could find within 100 miles of here). These were cut on an older ShopBot I found on Craig's List. It's a direct gear/pinion stepper arrangement so the resolution is about .003" which is fine for this kind of work. I made these bases because I think our customers need a quicker method of getting started (for a low cost) with the motor mount and wheel kits / caster wheels.
Why marry such fine aluminum machined products to a wooden base? Robotics is a personal hobby and everybody has their own preferences. As much as I'm an all-metal kind of crafter, maybe wood has a place in this application. It's one material that's easily workable with only minimal tools. It can be drilled without chipping, sanded and painted nicely with minimal skills, and produced at a very low cost. Within a few minutes you could have a robot platform ready to roll. Acrylic chips when drilled, metal isn't easy to work with, etc.
And what's with this round shape? Goofy-looking, I agree. But, round robots can free themselves more easily from chairs and other obstructions.
Some of the features of the robot base:
- 18" diameter
- 1/8" rounded bevel on all edges
- 12V Motor Mount and Wheel Kit + Encoders (27971) mount underneath the base with 1/4 x 20 stainless steel button head screws
- Drill patterns for one (or two) Caster Wheels (28971)
- Drill patterns for up to 10 Ping))) sensors using the Ping Protector Stand (725-28015)
- Battery platform for 12V 7AHr batteries mounts underneath motor mount bearing block with 1/4 x 20 stainless steel button head screws
The battery platform holds the battery in place, but doesn't prohibit it from fore/aft movement. You can secure the battery by mounting a small piece of angle aluminum on either side of the platform.
The goal was to provide the minimal number of holes and decisions necessary, leaving plenty of customizing and work for the robo-head. For example, no holes were drilled for HB-25s, Parallax 3x4 boards (BOE, Prop Proto Board, BASIC Stamp Super Carrier, etc.). There is plenty of room underneath to mount CCFL tubes for full-on 'bot pimping, too. This is certainly not an attempt to make a new standard in robot bases, as your craftsmanship and experimentation is what the hobby is all about. But, I hope that these bases will at least get people started more quickly.
Until we put a professional ShopBot or ShopSabre CNC router in Parallax, these platforms are coming from my garage (limited production capacity). We'll set up a gantry mill at Parallax as soon as we clear out a storage space (our former chip programming room). For now, we have 20 sets available at $29.99 and I can make another run as necessary. Until the marketeers get this on the web you'll just need to call our Sales staff and ask for one of "Ken's wooden robot platforms from his office desk" and tell them to sell it to you "non-stock". They should get these on-line by the end of the week at which time they'll have a part number.
What you get in the kit:
- 18" round robot base
- Battery pack platform
- (4) 1/4 x 20 3/4" stainless steel cap screws for mounting the motor mount bearing blocks to robot base
- (4) 1/4 x 20 1/2" stainless steel cap screws for mounting the battery pack platform to bottom of motor mount bearing blocks
- (6) 6-32 x 7/8" socket cap screws + nylon lock nuts for mounting two caster wheels to robot base
The drawings are provided under Creative Commons 3.0 license - use them freely and cut your own robot base if you wish.
I know you'll want a photo of a built-up robot. I can't wait to build one from these bases so it shouldn't be too long before I provide more photos. But for now you can get a general idea of what this looks like from an older photo I have attached (a smaller, 16" diameter base).
Hope some people find this useful.
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Post Edited (Ken Gracey (Parallax)) : 3/26/2010 2:01:35 AM GMT