HardWired - Upgrades and general build diary

[daveimi]

I have 2 x Gimson GR01's running on a Sabertooth 2x12. If you look at my build diary there's a video of it running up and down my kitchen It's had some hammer and is fine, they have a thermal/current cutout that will cut back in after it's cooled down.

Obviously a 2x25A is beefier but when my whole robot was made with parts from the bin it's been fab!

The problem with using individual ESC's like the botbitz is that you need to fork out for one for each motor, and then need a way of mixing fw/bk and lft/rgt to give you car type steering. Something like the Sabertooth does that for you, or a Scorpion but they're expensive.

Some expensive handsets will mix but they do weird stuff with limiting current to 60% like the DX5e's do with the Turnigy 85's etc. If your after something easy to use just get something that runs both motors off one controller and mixes for you.

[plargen]

the problem with the sabertooth is if you try pushing something it will probably start to judder and it can't handle the amps

and a cheep v tail mixer is less than £5 so mixing isn't an issue

[daveimi]

Yeah I agree. If you want to run big motors you need something that will handle Amps like the 85's do etc. I haven't had problems with Sabertooth and Gimsons so far I'm not on commission lol but they are easy to use.

[Flag Captured]

Hmm, I see... Though I won't be replying on pushing power, rather a great big spinner, so I may go for the Sabretooth, or even some moderately suspicious ebay speed controllers just for now, whilst I find the money to get a really powerful drive system going, hopefully for the championships next year if I can enter that...

Thanks for the advice though

[plargen]

i use these in both my bots

http://www.ebay.co.uk/itm/High-Volta...item51ad86eafc

in night fury im running a 4s lipo and 2 drills on each esc and the esc's dont even get warm even tho the motor are pretty warm by the end of a battle

you can also get them cheaper from china if your happy to wait for them

[Flag Captured]

That's perfect, thank you! Funnily enough, I did spot those exact ESCs earlier on yesterday (from a Chinese supplier) and I was about to post asking whether they were any good, answered my question for me there!

[Flag Captured]

In other news, I took HardWired to bits yesterday, rebuilt it as a beetleweight test bot type thing.
http://www.youtube.com/watch?v=SZHZO...?v=SZHZO0SVKkk

Handles pretty nicely to say it's using the servo speed controllers. My driving was so pitiful in this video because it was one handed driving, it's pretty good normally. Fun fact, the motors, wheels and gearboxes came from that Real Robots' Cybot.

[Flag Captured]

Getting the electronics for HardWired II through any time now, which means I'll be able to get to building a prototype out of MDF then have the body shell cut and welded out of some kind of steel. Running it on a 4S lipo with two drill motors and eBay speed controllers (also purchased a fire extinguisher that day) so that should hopefully run well enough!

As for weights and dimensions, I'm trying to keep the robot itself as small as possible, but then have the bar relatively long, it's starting to look a worrying amount like NST crossed with Last Rites, but it's copying from the best if it is. I'm going for about 10mm thick strips of steel down the sides and about 2/3mm on the top/bottom which sounds excessive but the thing is that compact that according to the weight calculators I've used, it should fit into weight nicely, even with 5.5kg for the bar. Was trying to figure out a system that'd keep the machine on the floor, but I might just buy a large magnet if they're allowed and use that, don't fancy having it hit something then fly straight out the arena!

The frame on the front is going to be a lot like last rites' - I'm not using a large plate of metal, just to try and save on weight a bit, because I do realise that going for a 5kg+ bar leaves me at most 8 and a bit kg for the rest of the machine which'll be difficult to say the least. I don't have the drive motors either for that weapon, because I ran a little bit short as it turns out so I've left the 6s battery, ESC and brushless motor for a later date. Which is good, I suppose, means I can look into alternatives that may actually be better than my first system - I'd like to run at higher than 6s, but I'm not entirely sure that's a good idea for now, being a relative beginner and all. Ideally, I'd like a 12s beast of a brushless motor, but again, might not be in my price range for a long time, something like that.

I've got the plans drawn down too, might get those scanned in and uploaded at some point so you can all see where this is going - I've designed it to be upgradeable, so that might be why there's some more unusual design choices on there at the minute.

Just thought I'd do a quick update on the machine's progress (even if it is all planning/ideas) since I'd not done one of these in a while!

[daveimi]

Do you have any sketches etc? I'm dead interested to see this!

[Flag Captured]

Thank you!
I do indeed have some, got a great many concept sketches that I've done for it (each one being a slight evolution of the last) and I might try getting some of them scanned in this weekend!

Just working on this bulkhead frame design, and then scaling everything electrical onto the design to make sure it'll actually work, and then I'll get them sorted!

It kind of looks like a 4wd Last Rites in the last sketch I've done, but with a shorter bar and much, much thinner proportionately! I'm trying to make it as flat as I possibly can, which is proving to be a bit of a task in itself at the minute!

[daveimi]

Yeah my first robot is an invertible pushy robot. Trying to get the whole thing inside the 100mm wheels has been a pain. Robot number 2 is non invertable with a lifting arm that can roll it back over lol.

[Flag Captured]

Very nice! That sounds good! my first wooden prototype was invertible, but it ended up getting horribly distorted when it came to building the thing properly haha!
100mm does sound tough too, but I think I've given myself an impossible task trying to get it as close to 60mm high as possible! Ideally I'd have liked it to have been nearer 45mm but that really is impossible - the idea is that if I can make it as flat as possible, there's less surface area on the sides where it'll likely get hit by spinners the most, so I can load it up with armour twice as thick as other machines might have - will definitely need to regear my motors down the line to something nearer 16:1 or something though because 32:1 and around 60mm wheels will be rather slow I'd imagine...

Hopefully everything else fits in the height allowance too, all the parts individually should be (I think my tallest is 5cm) but that's what I said about Hardwired, and I think that's probably one of the biggest bodge jobs combat robotics has ever known! I've actually somewhat engineered it properly this time though so, fingers crossed, it should be alright! Providing it doesn't all catch fire or something like the first version of Hardwired did haha!

[daveimi]

Yeah, I found getting the clearance right was hard and it ended up getting shimmed here and there to get it to run right. I'm not really that great at machining/accuracy so getting the clearances even top and bottom was not existent. I may or may not have had to give the whole robot a soothing caress with the planer to take a few mil off here and there.

I like it but it doesn't run that great on lumpy floors, I have a second robot with a lifting arm AND a hammer that's half finished so I dunno whether to push on with that or not or just enter my invertible one that's dead underweight.

[Flag Captured]

Clearance is something I've had major problems with thus far, but thankfully I'm having the body shell made for me, so I can't mess that one up badly as per usual!

Slight update too, Hardwired II is having some delays for now, until I can afford all the components - for now though, I'm working on Hardwired I again, getting that upgraded to LiPos and moderately reliable this time. Also want to put a lifter in there too, but I have literally £5 to spend on parts so I'm going to have to get extremely creative. The idea is that the entire lid will lift up, but I'm not entirely sure how I'm going to do that without an actuator...

Either that, or I might put those bike wheel bearings to good use and try and get that 10mm mild steel plate put to use as a disc on the back instead of the lifter. Not sure yet, I'd prefer the latter but I don't know if I'll be able to put a hole through 10mm steel with the tools I have at home.

[Flag Captured]

Another update, again with no real photos to show just yet, but I've finalised plans for HardWired I and the new HardWired I that I'm building.
To explain further, I'm leaving every main version of the robots I'm building as HardWired I, II, III etc. but they'll all have vastly different weapons, so H1 has the smaller spinning disc, H2 the bar spinner, H3 a flipper or something and each individual version of the HardWired machines will have its own subtitle, like a build version. I'm still deciding on the subtitle for this new HardWired I, but it's going to have an invertible wedge design with a spinning disc powered by a car fan motor on the back of it - The shell's going to be made out of steel (I hope) or a steel chassis and HDPE armour. Something like that, anyway. That's the one I'll try and enter in the championships next year.

HardWired at present is just going through minor changes, but it's staying an aluminium pushbot, albeit invertible. Going to go back to the old servo speed controllers as soon as I get the new chassis and all that built so I'll have two functional robots to mess about with. I'll have some photos on how that's going as soon as I can.

Reason I'm cancelling work on HardWired II for now is that A) I don't have the tools, materials nor money to make a decent bar spinner and B) I'd like combat experience before making something like that, since there's only so much you can learn by reading and watching videos...
That does mean however, I'm going to make it as beefy and insane as I possibly can. I'd like to use 12s LiPos and a respectively powerful motor, 5.5+ KG of bar spinner, hopefully over 10,000 RPM... it'll take a lot of engineering to make it work, but it's a much better project for the future!
I don't expect it to be the most competitive thing in the world, probably knocking itself OOTA a lot given what other spinners like that can be like, but it's worth a shot. Got some sketches too which I'll upload in due course too, which should be fun - it's still very much a work in progress though!