Update

Finally some progress on Carcinus
It was partly done before the champs but as I was rushing it I never took any pictures, so it's now gone from a pile of parts to something that looks close to completion:



Pretty basic setup. Two 12V drill motors controlled by Electronize 15A speedos, an Electronize switcher controlling the actuator and everything powered by two 9.6V, 3700mAh Nimh packs.

There's still a bit of work needing done to the main claw mechanism, which I hope to press on with tomorrow. I think I've hit a mental block with it; I know what needs to be done on it but just can't be bothered with the hassle of cutting and drilling a bunch of 20mm Nylon and 5mm steel. But ideally I will get through most of it tomorrow. The mechanism is going to be the opposite of the previous model - i.e the claws will close when the actuator retracts. I'm not sure if that method has any advantages or disadvantages compared to the push-to-close mechanism, but there will be a few more linkages involved. It just happens to be the mechanism which is more suited to this design.

In the meantime, it's started to get a bit of personality as I incorporated the power LEDs into some crab eyes:



Gimmicky more than anything but I like it

Started forming the armour for it too:



8mm thick HDPE bent to shape using a heat gun. The original plan was to stick quite religiously to the octagonal(ish) shape of the base plate, but as I was bending it, it was easier just to let the pieces bend over a larger radius. So there's a bit of an air gap between the armour and the internals, which is always a good thing. It was also going to wrap right around at the back but it was easier to bolt it on at the edges, so the gap between the panels (where the linear actuator mount is) will play host to some sort of chain flail that will cause deadly paint scratches to any opponent when the robot is in a full-body spin!

And finally, placing the claws to get an idea of how it will look:



I'm leaving the armour clamped overnight so that it cools in the correct position. With the curvy sides, it should make it harder for a spinner to grab hold - compared to the boxy old chassis - and it's also reminding me a little bit of The Stag, or its featherweight replica Staglet (for those of you who remember that). Overall, it's definitely a massive improvement on the first incarnation.

More work to come tomorrow; fingers crossed for getting some proper claw actuation!