Skipdiving Robotics

[Albear]

its been 10 days since your last post, updates please!

[daveimi]

My ultra rubbish featherweight made from scraps of wood has this weird body together, am now researching drivetrains and trying to find a massive sheet of ally from a bin somewhere. Will upload a pic over today as can't get photo bucket to work. In the same breadth you will laugh at it but the stuff has literally come out of the offcuts bin at b n q. This is the first time I've been pressed for an update its stressful! Lol :-)

[daveimi]

Not sure whether this is any good or not, it was only supposed to be a bigger version of Rancid for a bit of fun. It won't be invertible, and I'm not sure whether to alter it slightly before I get in to far. Was thinking of making a smaller wooden box that I can make invertible, the feather stuff is all flippers so invertible is the name of the game, beetles are all spinners hence the weird Rancid design. Anyway, you can see where this was going lol...

[Albear]

Haha! sorry didn't mean to press you i just love you build thread as my over-lunch read! id say invertible (or at least self righting) is a must, but i think a bigger version of the smaller robot (Rancid?) would be a fun continuation of the line! Maybe a weapon on the bigger one? im also assuming the green crayon is for scale lol

[daveimi]

haha green crayons rule when you have a 6 yr old and 2 yr old ransacking the place. Yeah come up with a better idea this weekend lol.

[daveimi]

Hello fight fans. Featherweight body finished using off cuts. Going to order a drive train over the next day or so. Think I've surpassed myself in the cheap and cheerful stakes, it was mostly built using the "by eye" method lol.

[Albear]

looking pretty solid! maybe neaten up the sides and it will look swell! that scoop is looking.. rustic haha

[daveimi]

Yeah I think if I measure stuff more thoroughly I might stand more chance. Anyway, excited to try a low powered drive train to see if hundreds of watts of power really is needed. My beetle weight will happily push a 5kg weight around so am interested to see if pololu 37mm gear motors will shove 10kg. In which case its a cheap, off the shelf drive train. I have the battery, receiver and speedo waiting to go in so really should hurry up and order some motors and wheels. I like trying quirky and untested products. I was the only person running pololu wheels I think at the beetle champs and they were utterly spot on. Dunno why more people don't try some of the off the shelf stuff more often.

[Rapidrory]

Well to give you a ballpark figure; to spin Richie's quite grippy 100mm wheel at 400rpm on a flat surface takes about 100W. Anything more than that would just spin the wheel faster.

I approve of trying quirky and untested products; Most of the things in Richie are rarely used in other feathers, were basically found in the scrap, and worked very well.. though sadly the quirky parts I'm trying out these days are rather more hi-tech :L

[daveimi]

Yeah I thought that, there's one of the build diaries where the builder talks about how you just need a lip to raise an opponent's wheels off the floor, and you can shove them around till your heart's content. Think it might be Jamie's. My beetle has 500rpm gear motors and will out-push two of the kinematic pay to drive robots at once. I know these are 3kg each give or take, so it just made me wonder. In feather circles I know that drills are standard, but drills at 7.2V still pushed opponents around in my first robot. So 7.2V x 7A gives about 50W per motor. The 37mm pololu stuff is cheap and 12V at 5A about 50 - 60W. There are then two ratios, one of which is pretty close to the 550rpm output of drills, and the other is 300rpm ish which on the 90mm wheels I'm planning might make it a bit slow. Gonna have a think for a couple of days. I'm leaning towards 300rpm as it's more controllable and arguably more torquey.