Robot picture

If that's your first, i can't wait to see the tenth! Excellent !

wow this is really great. You should keep up the good work, I am not an expert but it looks good :)

Could you help me by posting some data on the PVC... Ill look for the book at my earliest convience, but I need a good, easy to wrok, decking material TODAY... :-)

Thanks

Lexan's not too bad either. It's used a lot for structural components. Plus, places like pololu.com offer decent prices on custom lexan laser cutting.

Looks like a good bot Dave. What are you using to send and receive RF signals?

Alan

I have made flat plates of PVC by splitting a piece of sewer pipe lengthways, them warming it in the kitchen oven, before cooling it on a flat surface under a weight - a big bag of rice is good. I reckon you could form some pretty useful shapes that way also. Costs nothing to try, any building site will be throwing out pieces.

Thanks for the kind words everyone. I feel a little strange calling it my first robot because it's been through so many drastic changes and design phases. It began as a dumpy block of balsa wood with everything held together with rubber bands and paper clips. It continues to evolve. Next I think I want to ditch the servos and go with H-bridge motor drives for smoother and faster motion. Best regards,

-Dave

Hi Alan,

I'm using the rfdigital 433Mhz transceiver modules.

-Dave

Hi Dan

I just got the material from

-Dave

Try a local shop that makes custom signs. They will most likely have a stock of several thicknesses and colors where it is used in sign making. Perhaps they'll have some scraps that are too small for them to use but big enough for you, or maybe they'll be willing to sell you some of their stock.

But if you can wait a few days for delivery, Gordon's prices are hard to beat at

-Brian

Actually the PVC in pipes and expanded rigid PCV are fairly distinct materials, though both are made of polyvinyl chloride. Sorta like how a rain parka and a credit card are both PVC, but the properties are fairly different. Expanded rigid PVC is about half the weight and density of irrigation pipe PVC, and much easier to cut and drill. It has the cross-section of a softwood, much like pine.

(I also like to remind folks that if PVC burns, it emits a quite poisonous gas. In the hands of someone experienced like yourself it's probably safe, but warming up PVC in an oven, especially a gas oven, can be hazardous. Just thought I'd throw that out.)

For cheap/free -- though selection can be narrow -- is the discards at a sign-makers shop. Expanded rigid PVC is most commonly used for signage substrates and lettering. They cut out large pieces on a router, and always have extra chunks that just have to be tossed into the trash or recycling bin.

My latest book on constructing robot bases talks about this stuff in some detail.

-- Gordon Author: Constructing Robot Bases, Robot Builder's Sourcebook, Robot Builder's Bonanza

Does anyone know anything about clear styrene? A 4x2 foot sheet 4mm thick (that is how screwed we are in the UK wrt to units of measure!) costs around 20pounds (about 30 USD). Would I be better holding out for Lexan? I'm looking to a bot base about 50% bigger than a CD

TIA

PeterS

PdotSEEDatBTINTERNETdotCOM

Styrene is okay, but can be fairly brittle. You might want to test a small piece to see if it works for you. If you need clear, consider PETG, which is a form of polyethylene ("polythene" to those on the right side of the pond!). PETG is extremely durable, and optically clear.

Lexan is a tradename for polycarbonate, a name most commonly used in the US. In the UK there are other tradenames (like PC1000), but if you just call a local plastics outlet and ask for polycarbonate, they should be able to suggest the local brand. Polycarbonate is not an easy material to work with if you want really good results. It's a very hard and durable plastic, and it can dull drilling and cutting tools quite quickly. It's much easier to shape out with laser cutters.

Britishrobotics.com resells some of the expanded rigid PVC plastic bases I manufacture at Budget Robotics. There's a 7" 6mm thick round base, which is about twice the size of a CD. I see the price is £6.99, and the base is pre-drilled with a center hole and 12 equally-spaced holes around the outer edge. My personal preference is expanded PVC over either polycarbonate and acrylic ("Perspex" in the UK), as it's much easier to cut and drill.

Expanded PVC does not come in clear. The nature of its manufacture causes teeny-tiny air bubbles in the plastic, so it's always pigmented with a color, from black to white, and lots of other colors in-between.

-- Gordon Author: Constructing Robot Bases, Robot Builder's Sourcebook, Robot Builder's Bonanza