The photos should be viewable here: (This is the same link as the one in my previous post. If people could read that post too, that'd be superb thanks!)
https://www.flickr.com/photos/131745614@N05
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The photos should be viewable here: (This is the same link as the one in my previous post. If people could read that post too, that'd be superb thanks!)
https://www.flickr.com/photos/131745614@N05
Looks good :) - few things like links and fuses which you already mentioned obviously need adding, though it shouldnt take up much space, just remember you need an LED as well.
Design wise its basic of course, only simple suggestion id make is to make it look like a parallelogram from the side. It means when its inverted you always have one scoop still useable as a wedge.
Thanks! Yeah, it's about as basic as it gets but I'd rather play it safe for my first robot. :) Totally forgot about the LED - thanks for reminding me!
I thought that by having the rear wedge like that I wouldn't have to waste time turning my robot around if an opponent tried to attack from the rear/get to one of the sides. At least in theory anyway. And I'd just have to hope I won't get flipped! I did think about making the wedge like you've mentioned - might change it to that.
Thanks very much for the quick response!
Ok, so after spending way too long faffing about with these Black and Decker drills, (my nearest hobby shop couldn't help me out either.) I bought some Argos drills and I'm going to sell the Black and Decker ones on eBay. 3 of the 4 reverse thread chuck screws popped out relatively easily. However, even using another cordless drill I can't get this last screw out. Does anyone have any suggestions on unscrewing particularly tight chuck screws?
Thanks.
Probably for the best, black and decker are seriously budget. Turn the torque limiter down, then basically try and rattle gun it out. worst case drill off the head of the bolt then remove the rest of it when you get the chuck off but that will require buying a new LH bolt.
Ok, thanks. I've tried to jolt it loose again on low torque but it still won't budge. :/ Luckily I had the drills delivered, and one of the drill cardboard boxes has this big bash in it. Hopefully I can pretend the drill has been damaged as a result and I can exchange it for another one. :P
I assume you are leaving the motors in the drill casing when trying to remove the chuck? You should always remove the chuck before disassembling the drill as it gives you a better lever to undo the screw than just trying the grip the motor.
Yes, I've been leaving the drill assembled in it's casing when trying to remove the chuck. For the other 3 drills, I've had to use the Allen Key Hammer Whacking technique to unscrew the chucks once the screw was out, and for that I clamped the drill by it's casing.
Hello, just starting to sort out the wiring and stuff, and I was just wondering what would be an appropriate rated fuse for this LiPo battery, please:
http://www.hobbyking.co.uk/hobbyking...mah%204s%2030c
I've read that the fuse has to rated lower than the maximum current draw of the battery, but how much lower is necessary? I obviously don't want the fuse to be rated too low.
Also read that using Maxi fuses with the holder from technobotsonline can also be the removable link. Is that reasonably straight forward to set up? I've also noticed that the wire in the holder uses 8 awg wire, whereas the rest of my robot will use 12 awg (with the exception of the battery which uses 10 awg.) Does mixing wire ratings cause any problems or is it ok?
Not started building much yet but I pretty much have everything except a few bits and pieces, so hopefully progress should speed up soon!
Thanks!
Ok, so the other day I was trying to increase the bore of those Blue Bearing Boys wheels to 14 mm, so I could hammer in the Brass Inserts needed to attach the wheel to the drive shaft of the drill motor. (Finally got the damn screws out about a month and a half ago!)
But my drill made literally no impression on the plastic of the wheel. Pretty much right after the bit made contact with the wheel it stopped, leaving a few very minor cuts in the plastic. It's a relatively cheapo Black & Decker drill (Coincidentally it's the exact same model I was initially going to use for drive motors.), but I'm not sure if it's the drill's naff-ness that's at fault or some cruddy drilling technique of mine.
Just wondering how anyone else has gone about doing this? Is there some way of doing it or is it more so a matter of buying a drill with more oomph? Do I need something high-end for this sort of thing? Any help/responses would be really appreciated, thanks! (I hope you guys aren't getting sick of all us new folks asking so many questions!)
Also, just to show that I am actually building stuffs/making some progress here's snaps of the 99% complete battery mount thingy, and also slight changes/more details to the design of the robot. (Hopefully it looks marginally less boxy and basic now, though it still omits the fuse, link and LED.)
https://www.flickr.com/photos/134836804@N02/
I still need to drill holes in the base of the battery mount so it can be bolted to the base of the robot. Annoyingly my drill (or my potentially shoddy technique.) couldn't get through the 3 mm aluminium. :/
Again if there's anything horribly wrong with anything I've done so far please say so!
I'm also thinking of naming the robot Venator (Means "Hunter" in Latin.) if it's not been taken already.
Thanks for reading if you've made it this far. Sorry this post was so long!
Black and decker are generally pretty bad now so i'm not surprised.Putting holes in plastic most drills just fall though, its weird you can't do it. Maybe charge the drill and try again but...
I would advise getting a cheap drill press though mate. Even a basic one will mean you can do straighter holes than by hand (which you need for doing the wheels and stuff) and just general work its a great tool to have. I was without one for years and I don't know how i survived.
That^
Even a cheapo thing, talking £50 region, will serve you well. They aren't quality tools but they are a world away from handheld. I have owned and abused 2 such cheap things and with a bit of care they aren't bad.
Also, I assume the bore of the wheel is already fairly large. In soft plastics, drilling a hole to a size only a little bigger than its starting size often causes the material to tear and compress, which a lot of the time results in violently grabbing the bit. Either the part/drill shift violently, the bit snaps, or the drill stalls. Sounds like you're experiencing the latter. It's good practice with plastics to, where possible, drill a small pilot hole or none at all. I try to stick to pilots no bigger than 1/3rd the next drill's size.
What size bore are they to begin with? I did the melted-nut-bore thing a long time ago and if I recall melted them straight into the 12mm bore the 100mm wheels had as standard. Are yours not 12mm?
You can usually find small pillar drills going on gumtree for around £20 up this way. Your other option is a holder for a hand drill that turns it into a pillar drill.
Thanks very much for your responses!
Sounds like a good idea to hunt down a cheap pillar drill.
@Ellis
Yeah, the bore is originally 12mm, and the inserts are 15 mm across. I'd read in other threads regarding wheels that the nut insert could be hammered into the bore if it was increased to 14 mm. I've watched your videos where you melt the insert into position, but without the more precise movement of a pillar drill I was a bit cautious about trying it out.
I wouldn't hammer them in if I were you. It seems like a recipe for wonkeyness. Use a press or even heat the nut and use the drill press like a press (like Ellis's video) and its much better
Don't go for the holders, unless you need to drill a lot of holes in stone using a hamerdrill. (never found a pillar drill with hammer function)
In any respect, those are just a third rate backup.
I only can advice, go for a real pillar drill, and not the smallest ones either. I had one of those, and Kos made me a longer pillar, making it a lot more useable.
But on the other hand, those are cheaper than a good brand batterydrill ,and they can drill a straight hole.
I have this one, and I'm going to get a bigger one as soon funds allow.
http://www.contimac.be/Repository/Ca.../35015-900.jpg
Maybe this one.
Only major issue I've found, having owned two cheapo smallest-scale pillar drills, is that you need to stick some wood under the table so it doesn't flex when doing anything more than popping small holes in soft materials. Aside from that they have surprisingly little chuck wobble, etc. Of course I'd love to have a nicer, bigger piece of kit (with some slower speeds) but, funding.
I still strongly recommend you try and get one, it's a massive evolution from hand-held. Used via Ebay/Gumtree is certainly an option for cutting costs further.
As for the wheel bores, it seems that you'll likely need a pillar drill to do either thing: drill out the bore with any accuracy, or use it as a form of press to do the heat-insert method with the stock bore. Problem with hammering into the (probably nylon or polypropylene) wheels is that they will likely crack and wheel-wobble, even if it doesn't, will be bad.
With the heat method the plastic actually captures the nut in all directions, from the sides as well as rotationally. The wheels in our old how-to videos are still completely solid after dozens of harsh fights several years on. :)
Thanks for the responses!
I really don't have the cash for one of those bigger pillar drills, but I'll definitely check out getting a cheaper one.
And if I'm going to buy a pillar drill I'll use Ellis' melting method for the wheels rather than hammering it.
Thanks so much for your help!
Just finished cutting the HDPE. Could've been tidier, but it all fits together so it should be ok. Also the pillar drill arrived in the mail yesterday so I'll be able to assemble it all soon.
http://www.fightingrobots.co.uk/atta...tid=5460&stc=1
Good work
The pillar drill will certainly help accuracy
Looking good!
Just realised that it's been nearly a year since my last post on this thread, so I thought I'd make an update. Progress has generally been very stop/start as I live in halls of residence at University, so unfortunately I can't really work on the robot during semester time.
Attachment 5919 Attachment 5920 Attachment 5921
Although Venator isn't quite up and running yet it actually looks like a combat robot now! That's pretty much everything except the battery, steel wedges, power LED and mountings. I also really annoyingly blew something up in one of my ESCs about a month ago so I'll need to do something about that too. :cry:
But considering I knew next to nothing about electronics or D.I.Y. before starting this project I'm really happy with how this has turned out so far. :D (Just pretend those misaligned holes on the lid aren't there.) Hopefully it will actually work when I finally get to turn the thing on!
Looks really nice, good job!
How did you fix the side panels to the center frame? (those blocks between the front and back wheels)Quote:
Originally Posted by dotDominic
Thanks, Andy. :)
@CoolSpeedBot There's a 100 mm bolt which goes through the length of the block, with a barrel nut in the middle. Then there's a hole in the side of the inner bulkhead which allows it to be held in with a washer and nut. Here's a photo of one that was a bit iffy, hope it makes sense. :)
Attachment 5923
Right now it's the only thing that's holding the wedge and outer armour to inside - now I can see where the wedge actually sits I can bolt it to the inner bulkheads.
I see, thanksQuote:
Originally Posted by dotDominic
So I just tested Venator and it actually worked! ... for about half a second...
There was a bit of a poof around the removable link as I hooked it up. The negative terminal of the link has gone black and no longer conducts. Was wondering if anyone knows what I've just done? :? Is this due to a naff solder joint somewhere?
Thanks,
Really hard to say, generally smoke could be from anywhere if it's been going for a while but if it's been almost instant that it's happened I would guess it's a battery short. Or maybe that the link wasn't in all the way and it's arced across the contacts, but make sure the battery being shorter isn't the issue first
Ok, thanks for the help. Will look into that.
Get some pictures up, it will make diagnosis much easier.
I agree with tony that at first it sounds like a Dead Short, or possibly you have an ESC in backwards or something. Or it could be as simple as the link was dodgy and not up to the usual standard.
Ok sure, here are some photos. The circuit as a whole, the individual bits and then the link.
Attachment 5961Attachment 5962Attachment 5963Attachment 5965Attachment 5966Attachment 5967Attachment 5968Attachment 5969
Attachment 5970Attachment 5971
Also one of the motors has been making a grinding/crunchy sort of noise when I turn the axle by hand. It also moves a bit less freely, and didn't want to lock up with grub screws as well as the others. Could that be a problem related to this issue? It's still attached to a bulkhead here because I can't get it out without a thinner pair of pliers to grip the axle with.
Thanks.
EDIT 08/03/18: For those reading this in the future, turns out that wiring the fuse on the positive side of the battery, is a more correct way of doing this. So the order should be on the positive side: Battery terminal - link - fuse -*split to parallel*- Led, OR Esc - Motor.
I really wouldn't have your remove-able link that way round. Anything could fall on the male pins and short them together activating the robot. Also it looks like you've tied to pull far too much current through the XT60 and it's charred the end. Try using XT90-S with the female end in the robot and the male end as the removable link.
You also need to insulate the soldered terminals of your connectors, insulation tape will work however clear heatshink is best.
Hi Pinski, thanks for the response.
I will go ahead and sort out the link, then. I've used coloured heatshrink on everything - I wound a bunch of insulating tape with heatshrink underneath on the link because it was soldered at a 90 degree angle to the connector. The photo with exposed terminals is the link with the heatshrink/insulating tape removed.
I suspect the problem might be that you've wired your speed controllers backwards. The red and black leads coming out one side of your ESCs should go to the battery, and the two black leads coming out the other side should go to your motors.
From what I can see, the rest of the wiring looks okay, so I'd try rectifying the ESCs first then trying again.
OH DAMN SON!
Yeh, what Jamie said, man, how did I miss that! the 2 black leads are for the motors, the hint being it doesn't matter which way round the motor is connected. However the power supply into the TZ85A has to be red = +ve battery, black = -ve battery.
I fear you've fried both the TZ85As
:-| D'oh! That's a pretty big problem, then! Considering these two didn't smell, sound or look like the other ESC I blew up I think they should be ok. (They'd better be...) While taking these photos I was thinking to myself "There's no way I could've hooked up my ESCs the wrong way! How silly do the roboteers think I am?" ... Uh, yeah, don't answer that question... :P
I'll re do the link anyway since that is definitely busted and I want to make sure it's safe.
Thanks again for the help!
It's cool we all make silly mistakes, you make less as you go on, but they still happen and tend to cost more...
If it's any consolation, every roboteer will do that, or something similarly d'oh-ish at somepoint in their lives. You're not the first and you certainly won't be the last :)Quote:
Originally Posted by dotDominic
If the was no smoke from the ESCs and they don't smell cremated then they may well be fine. Just have to plug them in (right way round this time ;) ) and see.
Yeah, thanks guys. :) When I undertook this project I did realise much of the learning would come from things breaking - but I was expecting that to be in the arena, not before I'd even entered it! :P
Odds are that your ESC's are still fine. just give them a test (but the right way round this time). Unless you were spinning the motors backwards and forwards by hand (making the motor a generator) there is little that happens. reversing the polarity on the battery side of ESC's is most of the time the culprit for ESC's breaking (next to capacitors breaking off).