Sprouting Potato: 4wd Pusher

Just a couple of days to go before Botfest, so I thought I'd share one of the bots that I completed last night. Say hello to Sprouting Potato:

https://farm1.staticflickr.com/925/4...f9d1a478_c.jpg

It's had a few iterations. First it was gonna be a wedge-shaped pusher, then a servo-angled wedge pusher, then after a minor fail at AWS 55 with my other bot, Suspicious Houmous, I decided to make it a simple 4wd pusher. I should probably stick an 'L' plate on the back, as my driving is AWFUL. :p

Actually, I had an intention of letting my 7-year-old son drive, but I let him drive it around the front room and he just drove round in circles, sometimes breaking to drive it into a table leg or the entangling embrace of a throw blanket. Maybe he'll do better with an opponent to aim at.

It's not totally finished. The side armour needs a trim, and I need to fix the front screws better (some HDPE will do that, and create a buffer against the motors, too), and it needs decorating! oh, and it's a bit too slow. I'm hoping it'll feel faster in the arena.

The aforementioned Suspicious Houmous is also signed up for Botfest, but it had so many issues at AWS 55 that it needs a complete redesign. Two evenings and a morning to build a robot.. easy! :eek:

Looks good! I need to invest in some polycarb I think, looks the nuts... I'm also intrigued by the servo angled wedge, sounds pretty cool.

As for the rebuild, You got this!

ha! thanks for the confidence, but don't be surprised if SH is a no-show. I'll give it my best shot, tho!

the servo-assisted wedge idea was a bot with two large wheels at the back, and an armoured plate at the front that can be angled using a servo, so it can adjust if flipped, and can alter the angle against different types of bot. It seems like a shallow angle is better for getting under someone, and a steep angle is better at deflecting spinners or pushing. Not sure about that, tho, and it felt like it was probably a silly idea. :P

Looks very neat, much neater than some of my creations. When I rebuild Ikari, polycarbonate will probably be my port of call.

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The aforementioned Suspicious Houmous is also signed up for Botfest, but it had so many issues at AWS 55 that it needs a complete redesign. Two evenings and a morning to build a robot.. easy! :eek:

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Yeah, easy peasy :P What kind of issues do you mean?

Suspicious Houmous is a lifter, using a motor attached to arms via gears, and has a few issues..

To get it under 150g, I used 1mm polycarb throughout (the aluminium on top is purely decorative - it's a cut-up can of Guinness!), but it flexes badly when lifting, causing the gears to go out of alignment and the lifting arms to go floppy. Not ideal!

When it does lift, it pitches forward, which lifts its own wheels off of the ground. Also not ideal - it's supposed to be the other way around! Easily fixed by moving the front wheels right to the front. :)

The other issue is the ESC. I used a NanoTwo, as a DasMikro wouldn't fit, but between AWS and arriving home, something inside it broke. I don't have time to work out a solution (probably desolder the RX), but I do have a DasMikro in reserve. I just need to make it fit.

Here's what it looked like for AWS 55:

https://farm2.staticflickr.com/1770/...d9e68a79_c.jpg

So, I need a new 1.5mm polycarb chassis (maybe even aluminium), I need to move the wheels forward (which might allow enough room for a DasMikro), and I might need to rethink the lifting mechanism if it's too heavy (a servo would be slightly lighter than the motor/Vex29 setup, but I dunno how to attach the gear, and it wouldn't be 360 degrees without modification)

What could go wrong? :p

Suspicious Houmous is a fine looking machine sir, Having used a Dasmikro literally last night, they aren't really much bigger than the Nanotwo, the issue I can see is the RX, the one I have is huuuuuuge (it has to poke out the top of the current shape).

As for pitching forward, could you not add a little 'leg' to the front, similar to Okracoke's Shu! to give a lower effective leverage? Gotta be easier than starting again.

The shell needs rebuilding either way, so I may as well improve it while I'm at it. :)

There's not much room for a leg, as the bot is already 4x4x4 - the lifting arms have to be at a 45 (ish) degree angle to fit into the 4 inch cube, so the main body has to sit flat on the bottom. The main reason it's so big is because I had trouble fitting everything inside it. It's really crammed! Here's a photo of the underside..

https://farm2.staticflickr.com/1766/...e2256d5e_c.jpg

I had to leave space for the gears, so stuff wouldn't jam into them, and the axle going through the middle really gets in the way. Also, a lot of space is lost externally due to the arms. It all adds up. :-|

I have plans, though! Maybe too many plans..

They look absolutely fantastic (I think?). I'm sure you won't come last, that's reserved for me :p

Oi! Theo, back of the queue mate! I've had my name on last place for weeks now :rofl:

Fight you for it :p

Bring it on!

We'll have a whiteboard and control each other's, then we'll see who's last!

These both look great! Nice work man! cant wait to see them all on Sun!

Bad Wolf

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Originally Posted by Theo

Bring it on!

We'll have a whiteboard and control each other's, then we'll see who's last!

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Yeah I'm *so* going to get whooped, can't wait to finally lose and claim my rightful title!!!

But yeah, should be a good day, can't to see everyones 'bots in the flesh... erm, plastic :uhoh:

Graham, are the weapon hubs on SH an of the shelf component? Stealing some ideas from SH to upgrade Pullover for next time :proud: (sorry). The lifters seemed to work very well, and I'm re-engineering the grabber arm to go back for enough to *actually* self right every time. Hope you don't mind the blatant design theft...

course i don't mind! i first saw them on one of georger's bots (the hammer one), so i kinda nicked the idea, too. :)

they're pololu 3mm mounting hubs: https://www.pololu.com/product/1079

there is also something similar out there that has only two mounting holes and is long rather than disc shaped, but i don't know what they are

Aw thanks dude! been looking on and off for these all weekend, I need to improve my google-fu I think.

It makes it better that I'm building the arm Inspired by Hummus and not the same as... in fact, I like that, might write that on the bot... anyway, thanks for getting back to me, time to get cracking!