That hammer is awesome! By the by, what kind of battery is that big boxy thing on the stripped down picture of drumroll above? Is it a huge amp-hour rating?
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That hammer is awesome! By the by, what kind of battery is that big boxy thing on the stripped down picture of drumroll above? Is it a huge amp-hour rating?
Thanks Dave, yet to test it properly to see how effective it actually is.
Had a look back at the picture you mentioned and can't see the part you're talking about. The battery is a small 5-cell lipo pack that is behind the left-hand drill motor and under the receiver, but it's not particularly noticeable in the picture (I mistook it for part of the base plate).
Working from left to right, the stuff on the workbench in front of the transmitter is the bulk of the electrical/electronics assembly, then on the robot itself there are the two drill motors, the aforementioned battery and the brushless motor and speed controller for the weapon (the speed controller being the black box in front of the right-hand drill motor, not sure if it was that you were referring to).
Hope that helps!
are you classing that as a hammer or axe?
xx
I'm classing it as a unique device, hereby referred to as a 'smashy smashy'.
On that note, I'm just gonna leave this here 8)
http://www.youtube.com/watch?v=WOSJBug1Y7I
Update
Managed to give a little bit of attention to Scar today for the first time since getting it. First job was to remove the inner box-section 'structure' that was there, presumably for the benefit of the old components that used to reside in it. Since it's getting a complete revamp in terms of its internals, they had to go. They were welded in so I predicted much use of angle grinding and swearing (it's quite tight!), but I quickly realised that the welds weren't that strong and was able to just bash each piece out with a hammer. Easy as pi and much more space now:
Attachment 3659
I then started messing about with possible drive setups. The two motors I have to hand are a 300W scooter motor and a Bosch 400. After some deliberation, it's looking like the Bosch is the more viable option (unless I come across better options). The plan is to run it on a single-stage reduction, very similar to Tanto Jr/Scot-Bots housebot, although I'll maybe gear it for more torque and less speed. Might need to make some wheels from HDPE and cut/screw the go-kart tyres on though as they're currently not best set up to run on a shaft.
Attachment 3660
If you click on the picture to enlarge, you may or may not be able to see the wheel shaft sticking through at the back, just below the welded nut. On each wheel, these are hollow and I'm assuming they just went over the wheelchair motor shaft and got pinned in place. But I'm planning on mounting a solid/fixed shaft on either side of the chassis, with wheels running on bearings. There's no scope within the current wheels to do this hence the possible need to cut and paste.
That's all I managed today, so now I need to source another Bosch 400. Used to have a second one as well - got them when they were going cheap on eBay - but sold it on a few years ago. D'oh!
Update
Kinda forgot about this thread now I've got a FB team page on the go, time to bring it up to speed.
Spent some time over the past few weeks building a robot around the axe module I made pre-champs. Rather than try and get it all in weight when attached to Carcinus, I figured it would work better as its own machine and it means I can tick axe-bot off the list. Back when the Bosch 400 was intended for it, the name I had was Grond (a LOTR reference), but now it's called Onyx. No particular reason other than I think it sounds cool, and no connection to the mineral.
This is how it looked from the back shortly before it appeared at a Scot-Bots talk a couple of weeks ago:
http://i31.photobucket.com/albums/c3...ps3f0bce18.jpg
Since then, the Scorpion XL has been transplanted into Carcinus after I blew up one of its ESCs by running it on too high a voltage (Mtroniks, 12V max) and Victors have taken its place. The LED strips have also gone after I forgot that they too only operated up to 12V and proceeded to plug them into a fully-charged 5-cell lipo pack. The receiver, RX battery and link all now reside in the front right-hand section.
Filmed a test of it today which had mixed results. Overall, the robot is very nippy and, although the axe won't cause much damage, it's really fun to play with and self-rights the robot nicely. The Victors don't offer nearly as much precise control as an XL, something which I've never noticed previously, so will look at getting another Scorpion or some TZ-85s somewhere down the line. The axe gearbox also jammed up as a result of the pins coming out. The same thing happened at the Scot-Bots talk and although I repaired it, it wasn't enough. I reckon I can redo the repairs more sufficiently for it to work for sustained periods, but if it's going to be a persistent problem, I might look at making the transmission two-stage, with the first stage being a timing belt and pulleys from the motor, just to try and reduce shocks. Probably won't happen before Edinburgh though, so will see how it gets on then.
http://www.youtube.com/watch?v=8aObqgv2r2E
Need to grind some bits off the chassis somewhere too as something's fouling on the floor, hindering the drive a bit.
Looks good!
Indeed, is looking nice. Also lookign forward to seeing more of scar
Update & Event Report
So I managed to get Onyx finished up a few days before the Robots Live Edinburgh event, with some last minute spare modified drill shafts made for the axe as I expected a few failures. This is how it looked prior to the event:
http://i31.photobucket.com/albums/c3...psb8dd5c80.jpg
The curved scoop is all 5mm steel; took a bit of work and not quite as neat as it could be but it's solid so I'm pretty happy with it. Also shortened the axe arm and curved the head a little as it looked a bit bland beforehand.
All was working well in the run-up to Edinburgh but when moving the arm after arming-up in the first fight (and even before the fight started) the axe jammed. As I suspected, the pins had failed again so I just ran it without the axe in the first fight.
The drive is incredibly fast but I struggled with controlling it a little (too used to the precise nature of the XL) and ended up smoking a motor by the end. Swapped that out during the break but ran out of time to repair the axe, so went into the second fight, again weaponless, and got flipped pretty early on. Had more drive issues but it was just with reverse-threaded screws coming loose so I sorted that out with a bit of Loctite. Finally got to repair the axe but turned out that the grub screws were looser than I though so, although the axe could fire, the torque limiter was kicking in when the robot was upside down so it still couldn't self-right. Eventually sorted it and got it all working well for the fourth and final fight and got a few full-strength hits in before the axe mysteriously started getting really slow. A quick look inside revealed that the screws holding the motor and its mounting plate on had come loose, so the gears weren't meshed properly and had been slipping.
It's an easy fix which will get done, but I'll be looking at fitting the 300W scooter motor in somehow now. The drill motor just isn't designed for the punishment of an axe weapon and will just be a long-term hassle if I persist with it. Weight will be tight using the scooter motor but it's currently at 12.9kg without any form of weight-saving having taken place, so I'm hopeful that I can manage it somehow. The increased reliability will certainly be worth it.
For once, Carcinus was pretty low-maintenance and only had to have a little one-minute repair made to the actuator between shows. Still ended up in the pit a couple of times but I think that wasn't directly connected to my dad's driving this time!
Once I give both machines the necessary TLC, I'll work out plans for heading forward. Not got any more events down as definites this year, but got a couple I'd like to get to, circumstances permitting. Got a lot of work to do on Scar, want to get a couple of beetles up and running and Drumroll - which has been in pieces since the champs - needs rebuilt once it's had a bit of a redesign. Also got that grabber/lifter waiting to be done on top of any Scot-Bots stuff that'll need doing over the year. Eeeny-meeny-miney-mo!
Cheers for the report. Love how little things can turn into anoying problems. Its looking great and I think a 300 watt motor will do it good. Not for damage but for flair.
Looking good. Enjoying these axe bots :)
Update
Started looking at swapping out the axe drill motor for the 300W scooter motor. Finally managed to get the existing sprocket off the motor (turns out I was grabbing the wrong bit) so first step was to see what the damage would be:
http://i31.photobucket.com/albums/c3...ps5b9e89d2.jpg
Lose 900g at the same time as fitting a chugging great big (and more powerful) motor? Challenge accepted!
Next step was working out how to try and fit it in to the existing interior layout. I thought a lot of stuff would have to be rejigged, including the drives, but simply by cutting one of the bulkheads in half (saving 370g) I was able to bolt it in at the back.
http://i31.photobucket.com/albums/c3...ps68dfdf1d.jpg
Weight distribution still seems good; the motor weighs 2.2kg and the 5mm steel scoop at the front is probably a similar amount, so the kilos are well spread over the drive wheels. That's all I managed to get done on it today (forgot to take a picture with the motor fitted) but I did have a cheeky little test of it. Here it's running on a 5:1 ratio at 18.5V(ish), so theoretical rpm at the axe shaft should be around 385rpm, not taking losses into account, so almost four times as fast as the old drill motor setup. It's just a short video as I was doing a direct connection to the battery and promptly soiled myself (not literally) when it fired.
http://www.youtube.com/watch?v=R3pfreELsLo
I'm particularly loving the air time it gets, which is more noticeable in the slow-mo replay. I think when it's fully under RC again, it'll be crazy when it fires, which will look immense. Not fussed about damage, although I expect it to do more now, but as long as it has epic spasms, I'm happy. Just taking wagers now on what will break next. Already eliminated the first source (drill motor) so I expect either the chain to be a regular snapper or the sprocket on the motor to strip teeth or break its welds (not much boss left on it).
Great improvments so far. Best of luck shaving the 900 grams
I saw it on Facebook, its a beasty
Weighs 13.5kg in this video, all that's left to go back on is armour, which currently weighs 600g. Still haven't done any weight-saving though and I can downgrade some of the armour, so I reckon it'll all be fine. Enjoy :)
http://www.youtube.com/watch?v=60-9-927nPw
That's got some serious kick, wow! I'd prefer not be under it when it fires now, damn...
:lol: great vid, that does look like its got a good bit of power
like the video, do you have a job !!!!!
looks really good motor still looks abit loose on mounts possibly lots of flex in video, cant wait to have an axe off some time soon if I ever get round to fixing my cracked chassis thanks to ls4
good job :D
Thanks guys. Yeah the motor looks a bit loose (especially at the bit when the axe head gets stuck) but it's solidly bolted into the machine; the flex is coming from the polycarb baseplate. Hopefully it's strong enough for the job, but with enough flex so as to absorb the forces when the arm hits.
Definitely up for an axe-off (get Little Hitter and Asgard in there too), got more chance of the axe bot still running after an event than I do with Drumroll (a drum-off will take place one of these days!)
Just uploaded a couple more photos, just to better show the interior with the motor fitted:
http://i31.photobucket.com/albums/c3...ps2cf54259.jpg
http://i31.photobucket.com/albums/c3...ps71af0578.jpg
It's absolutely mahoosive in relation to all the other components. The drive is a little bit squiffy at the moment though; not sure if that's to do with the 2.2kg of motor being off-centered or the fact that I've got two different speedos controlling it (had to switch one of the drive Victors onto the scooter motor and use the 25A Botbitz from the old axe drill motor for the drive). Will probably fit TZ85s for all three channels soon so will see what happens when that's done and everything's properly bolted back together again.
are you using a speed controller for the axe? if so, how are you applying full power instantly?
Looks really good so far Jamie. Have you got any limit switches on it?
Yeah I'm using a Victor 883 on the weapon at the moment (will be changing to a TZ-85 when I move across to them). Just controlling it by throwing the transmitter stick to the left or right as quickly as my fingers will allow, so not completely instantaneous, but the difference is negligible. However in the 10 years I've had the transmitter, I've never once used its trainer switch (which is a spring return switch) so I'm planning on rewiring that onto the channel pot so that I can flick the switch to get instantaneous power yet still retain proportional control for retract and demos.Quote:
Originally Posted by Bodge Job
Cheers Dan, no limit switches fitted on it (they'd probably get destroyed) but I've found that just judging it by eye seems to be sufficient. Because the joystick and switch both spring back to the centre/off position, it's easily enough to let go when it's either hit something or reached its travel. Will be adding some rubber absorption/protection to the chassis at the travel limits though.
Hi Jamie, I like your new weapon videos.
Have you tried experimenting with a larger gear-ratio for the axe? I'm guessing the sprocket on the motor shaft already has the fewest teeth possible?
Cheers Sam, haven't played around with different sized axe sprockets yet. It did cross my mind when I first converted to the scooter motor but at the moment I'm happy with how it's running so will leave it for now. And yeah, the motor's currently got a 9-tooth sprocket on it which is the lowest I could go before running out of boss material!
Update
The battle for weight loss has been won! After drilling 140-odd holes, I managed to get Onyx down to 13.6kg:
http://i31.photobucket.com/albums/c3...ps266de405.jpg
The only problem is that my scales are only to one decimal place, so it could be anywhere between 13.61kg or 13.69kg. I thought about drilling more holes to be sure but then I realised that:
- I'll lose a bit of weight when I swap from Victors to TZ85s (might even put the XL from Carcinus back into Onyx as it'll be lighter)
- I can ditch the RX battery, mount and switch and use the BEC on the XL or TZ85 controlling the weapon
- I estimate the tether to weigh around 50-100g, and tethers aren't included in the weight (will actually weigh it to be sure)
So the combination of those three things should put it safely underweight; I'm also hoping there will be enough spare to afford some protection to the currently-quite-exposed scooter motor, but we'll see.
Also, it you ever wondered what 375g of HDPE swarf looks like, here you go:
http://i31.photobucket.com/albums/c3...ps3b43194e.jpg
Great stuff. Love the desk covered in swarf. Think mine may look similar soon.
If your scales are rounding to the nerest tenth of a KG then wont it be between 13.55 - 13.64?
That's a good point actually, never thought of them rounding like that. Won't really know for sure until I get them on a more precise set of scales. The only event where that will be strongly enforced will be the Robo Challenge champs, but I'm hopeful of getting along to at least one RW/RL event before then so I might be able to check it out on their CO2 scales (if they go to two decimal points...)
When you fit the tether, please could you show me, so that I understand what exactly they are?
Yeah can do. It's already fitted but I will be taking it off and weighing it so will get some pictures when I reassemble it.
OK, thanks.
Don't use there co2 scales just guess will be more accurate 300gram difference on no toy from RL- Robochallange scales
that was alot
Update
Been doing a little work to Flatulence over the past couple of days. It's been sitting for about a year needing its armour completed and I've been putting it off for ages because I expected it to be fiddly and annoying to do.
I was right, but got it done eventually. It's quite thin, at 2mm, but seems reasonably strong. The bottom half is 4mm HDPE which will stand up to the spinners a bit better, but I'm fully expecting all of it to take a beating. At least it completes the look a bit more. Ignore the multiple fail-holes where the armour layers meet:
http://i31.photobucket.com/albums/c3...ps1f0d2f19.jpg
http://i31.photobucket.com/albums/c3...ps2fb53569.jpg
http://i31.photobucket.com/albums/c3...ps4ee5572c.jpg
Currently weighs 1083g so got just under 500g for....stuff. The only thing I want to do is replace the ali flipper plate with a steel one with triangle wedges at the front to finish the shape off and offer some protection. Will also need to stick something on the top of the flipper plate to help it self-right as it only rolls halfway over before getting stuck.
I'll never expect this to be a serious contender as I started building it two years ago and since then, despite not even having an event yet, beetleweights have already stepped up a level. But if nothing else, it's good fun to play with :)
http://www.youtube.com/watch?v=bYRiReRymms
Love it :)
what voltage you running the servo off?
Cheers Harry. The servo's just plugged into the receiver, which is getting a 6V, 5A feed from the BEC. Was originally using the BEC in one of the Botbitz ESCs but it was underpowered, especially since it's a beast of a servo. All good now though :)
Are you going to finish the BW Drumroll?
Probably at some point down the line, yeah. Not with that chassis though, would make a new one out of some thicker/more rigid material, and need to get a smaller diameter brushless as I planned to have the current one pressed into the drum tube, but I couldn't get a tube with a suitable ID so just plan to revert to a pulley transmission.
Jamie, okay cool. You could probably get away with overvolting that servo for a bit more speed and power if you needed it.
cheers.
Update
Well it's finished, paint and all:
http://i31.photobucket.com/albums/c3...psb61f902b.jpg
Happy with it weighing in at 1.35kg. After several attempts at different attachments in order to get it to self-right - and getting nowhere - I eventually resorted to hacking the servo for 360° rotation, allowing the flipper arm to travel further back, turning the robot back onto its wheels. The downside is that I had to cut away some of the back armour which now spoils the look a little, but functionality over image!
http://i31.photobucket.com/albums/c3...ps7e17f085.jpg
A lot of the wiring was pretty exposed due to that too so I've redone it all, doing away with the connector block and just splicing all the wires together where needed, and have been able to pack it down to protect it more. Finally, needed a bit of protection on the insides when the flipper is up and still had to add an LED, so bazinga:
http://i31.photobucket.com/albums/c3...ps335a200c.jpg
So that's that for Flatulence just now. Need to get some practice in controlling the flipper as going to 360° completely changes the dynamic of operating it, but nothing else apart from that to do :)
Love it :)
Need to put it on a spring action trigger, either rudder on the remote or use a DPDT switch like I do, middle as neutral, full power either way.
It's on the rudder channel already, it's just that I've been used to flipping a switch and letting go when it was set up like a normal servo on the throttle channel, where it would stop when it reaches its limits. Now I just need to familiarise myself with the new fire and retract movements, especially for quick, repetitive flips as I don't want to hold it too long in one direction or other and have the flipper either travel too far for a quick reset/attack or be stalling the motor too long at the ends of travel.
It's not challenging, it's just to get comfortable with it so I don't have to think about it when in the arena.