“You just got bombarded with 26 videos” Yes I did. That’s what I woke up to when I opened RU-vid this morning. I opened my subs and all I see is a wall of just cuz robotics. Took my about a minute to figure out that I now have something to actually watch now(there is nothing happening on RU-vid lately). Love this bot. Cool design. I’m almost finished with my first beetle. I’m gonna be very tight on weight.
Yeah I was pleased with the grip for sure especially given they are getting covered in sawdust and debris and still working. I have a tutorial vid where I cast wheels for my 12lb bot and it's the same exact process for these, only difference is the hubs and molds (obviously), and I used a softer and gripper shore 30A urethane because the 40A is out of stock everywhere due to a global urethane supply shortage. I also used Micah powder dye instead of liquid which is much easier to get a decent color without ruining the curing of the urethane since it isn't diluting it. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-U-_xxI6qvlg.html
I was really excited to see how Shrapnel Mine performed, it's one of the more unique design's i've seen from an overhead spinner. (or is it underhead?) I don't think the floor did you any favors, but i'm impressed how well it did perform, considering how experimental a design it was. I really enjoy these event recap videos, looking forward to seeing how Division and MM did!
Thank you! I'm thrilled it worked at all, I honestly was very afraid it wouldn't work at all, glad to be wrong. Clearly lots of room for improvement as well
It's exciting to see this in action since it's such a unique design for a saw. Shrapnel Mine being underweight for its first ever appearance also has an arguable benefit that there's weight to allocate into improving the bot. Bots are going to have teething issues, and seeing where those issues are and having the weight to allocate into fixing those issues seems very good for improving the bot from its first iteration. There's also a moral benefit of knowing the bot's core design is solid enough to perform when underweight, so it's more likely to perform well when it makes weight.
Thank you! Yes very true. Much better to have a lot to play with since the weight distribution sucks currently and moving existing weight backwards is a lot harder than adding weight at the back.
I'm disappointed my controller broke because I would have liked to exchange some hits with Shrapnel Mine but I'm glad to see it did really well at the tournament!
I still like this bot very much. It reminds me a lot of Red Devil, which was one of my favorites of all time. The way it grabbed and buried into Witch Doctor was a thing of beauty - and I love its grabby arms in general lol
Shrapnel Mine reminds me of a story I read once. It was about mice who were at war with weasels. The weasels had won their most recent encounter, because of their armor technology. This one mouse was able to get his hands on a weasel helmet, and bring it to his fellow mice. They made their own suits using the technology, and went off to battle the weasels once again. But then it started to rain. The mice’s suits became filled with mud. Mobility became difficult. When they finally made it to where the weasels lived, the mice discovered that the weasels were not wearing anything. And with their large agility advantage, they easily beat the mice once again. Shrapnel mine reminds me of that.
Man that thing is cool! I also agree it would be neat to see at a heavier bot. But I totally understand such things are not cheap and the destruction level is even higher so it might hold up.
Great to see ur experiment showing great results. And love that countdown and celebration sequence. Would a diamond saw would work too? How about adding a wedge variant of your pinning bar? And adding some armor? Since u said it's under weight, it should probably make it more solid and hopefully an exciting entry for next years NHRL(assuming u will be taking Shrapnel there).
@@JustCuzRobotics Oh...must have missed that. But I really love ur innovative approach to bot building. I still think u should add some armor to shrapnel considering the damage beater bars can dish out.
@@JustCuzRobotics Reminds me of what Donald Hudson said on a Battlebots podcast. Nothing is more satisfying than seeing your bot do exactly what you built it to do.
nice to see slightly different take on spinner, also i always have a great respect for people coming with dfiferent than standard design robots, and joke bots
With 10 more oz to work with Id definitely beef up the saws drive system to get more speed and go with a like a 6s battery so that saw never stops lol love the builds!
So far I have never tried to scale my designs, I tend to prefer building something totally new in every weight class. Every weight class requires totally different construction methods, making it only minimally faster to scale an existing design compared to designing from scratch - every single part needs to be redone from scratch anyhow. That said... I have plans for a 12lb full combat bot for 2022 which may have inspiration from a larger robot 🤔😊
@@JustCuzRobotics tbf the half control - half spinner is catching on in BattleBots. We got Whiplash saw blaze and skorpios as some of the best examples. Shapnel Mine's weapon system might be the next step for this type of robot. Because it's designed not just to control the match's pace, but it also attacks the one area that simply cannot be protected without exceeding weight limits.
It would be nice if the linkage movement of the forks had a lower position that lifted the sharp point off the ground and allowed you to skate across the floor.
the hooks on the top of the forks seemed to make the saw get less reach into the underside of bob in that fight, and they did get caught on the egg beaters, not sure if you're want to get rid of them but just a thought
Thanks! Imma be honest I do not intend to fight many robots with egg beaters attached 😂 I want some sort of backstop but the forks aren't as shallow of a slope as I thought so riding all the way up is way harder than I had assumed it would be. I think I'll probably make them hook over like 100 degrees instead of like 150 degrees, and be a lot stubbier. Also considerring making the saw arm longer to get more bite into opponents and maybe even bigger diameter saw as well, we'll see
Gotta say, it would be neat if you could modify this robot in a way that had 2 arms on the sides for grabbing bots, that moved in tandem with the saw arm which should stay exactly the way you have it, but what I'm picturing, is 2 arms closing to grab the target, while the saw comes down on top of them at the exact same time, pretty much exactly how Deadmetal housebot from the old robot wars used to work, except instead of having the arms and saw move independently, they could be connected with joints that move everything in the right direction, because you'd most definitely need more weight to hold more servos.. or anything else.
Interesting idea. The design was motivated by fighting vertical sinners like I said at the start. By hinging the movement vertically its extremely strong against vertical plane hits. But I'm afraid a horizontal spinner could demolish the forks. I think if the arms were sliding in from the sides then a vertical spinner would demolish them easily as well. I do want to come up with a better answer for horizontals tho. My only plan currently is replacing all the forks and linkages and saw entirely with a lifting wedge mounted straight to the servo, though it was basically an afterthought.
Yep. That's one thing I wanna address next time. But lower start angle means more angular travel to get to vertical which means the entire linkage geometry changes... It snowballs really fast. If I can do that without having to remake the baseplates I probably will do so, those were the most expensive part aside from the CNC servo brackets.
@@JustCuzRobotics what if the forks were just not a straight line? Like the very bottom half inch could be much more shallow, then it goes back to the current angle with an elbow bend. Or maybe a smooth curve.
I need to keep the overall distance between the pivot point and ground contact point similar, but that's an option as well. I'll probably 3d print a few different options to try out, maybe a mock 3dp D2 kit for geometry testing too
What is that spinning blade supposed to do? It doesn't have any reach. You're just pushing the other robot with the two side 'arms' and then you have maybe 2-3 millimeters of cutting depth.
Any reason why the wheels don't just have the large gear printed onto the hubs? I've been doing that for some of my bots. Why two parts with the hex connection? It seems like a single part would've more robust.
Partly because that way it prints with no overhangs and no supports, partly because it was carried over from the prototype phase when I was trying a few different materials, and in large part because the hubs are TPU. TPU hubs need to stay since they directly get hit. TPU gears I haven't tried but I expected the teeth would bend and it wouldn't really work. But I'll probably try it out.
@@JustCuzRobotics that makes sense. Maybe it just needs a larger mating feature since there's really no constraint if both sides are 3d printed. My printed and cast wheels are PLA mostly but they're interior and hard to damage. It wouldn't work as well for yours. Maybe a multinozzle printer like the new Prusa Max could print a single part with dual materials though and give you the best of both worlds.
Haha yeah I don't really wanna spend $2500 and wait 5 months to find out. That printer does look amazing tho. I actually originally designed the wheels to be able to screw onto the gears with 2 screws, I just accidentally left those holes out of the last gears I printed. I'll likely just use that so the hex is redundant.
I plan to do a whole video about this topic as a 4000 subscriber special. Short answer, as much as you are willing to spend, but probably at least a few hundred dollars upfront. Lots of buy-once-cry-once items that are costly but well worth it in the long run like tools, 3d printers, batteries and chargers, and more durable components.
@@JustCuzRobotics So to be competitive you are looking at no less than 1-2 thousand? Also, I realized that I didn't specify weight class so I'm guessing the price you gave me was for the 3lb robots? Is there a reliable website that you guys use for parts information ect? Im an old guy that needs a new hobby and I love watching the videos. I know the bots on TV are crazy expensive but it sounds like the 3lb class is something I could possible afford. Thanks a bunch for the info !!
No problem! I don't think that it would get into multiple thousands when just starting out. You can get a really good transmitter, battery charger, soldering equipment, cordless drill and hand tools for like $300-400. Cheaper versions of all that for
The motor side drive gears are steel, the interfacing gear that is printed is a $0.30 3D print but would easily be a $30 machined metal gear and would weigh 4X as much. I think I would rather the motor mounts be metal actually than to make the gears metal. Having more rigid drive shaft to motor shaft spacing is pretty key. And I think that I can make those mounts on the tormach myself, but the gear teeth are too small to cut conventionally.
@@JustCuzRobotics I know aluminum tends to weigh 2x as much as plastic and steel 2x that but.... Either one would likely eliminate the shearing problem and you were too light on the back anyway. :p (And they could be skeletonized, unlike the printed one.) BusterBeagle3D on youtube makes a home shop scale Injection Molding Machine. Do you think an Injection Molded drive gear would be better? Or do you think adding reinforcement pin/staples would solve the shearing problem?
Laser cut plastic acetal gears would be just as good as injection molded but a million times easier and cheaper to make. Also steel is 3X the density of aluminum, aluminum is 3X the density of plastic. Steel is 2X the density of titanium.
The howl "get them from below" thing is overengineered. 1, your weapon takes like 3 seconds to be used 2. it only works when pinned and good luck pinning bots with more weight that wiggle around and got weird shapes. Your test at home- a flat non moving disk- thats far from reality 3. clearly you need stronger batteries. didn't you test a full "endurance run"? like just letting it spin 5 minutes with it all on Oo?
Keep in mind this video is almost 2 years old and I learned a lot on that time. This was a proof of concept not designed to do that well. 2: My newest beetle SSP is 2.25 pounds in it's lightest config and literally shoves around and pins bots over twice it's weight no problem. It's all about having grippy wheels and enough drive power, the weight isn't that big a deal. It's always easier to add weight than remove it. 3: already addressed this in a redesign, I switched to a 4S LiHv and it did a bit better but still kinda sucked for other reasons. Like I said needs time and attention I haven't really had yet.
You're not wrong. I definitely have plans to make this bot a lot better but haven't had time in the last year or so to really improve it. I think the concept if executed better can work well.
I really think I had that fight until the 2:30 mark! But the D2 did go on to get second place in the weight class so I can't feel too bad about that loss.
@@JustCuzRobotics you definitely had it beat, the robot performed really well all things considered, and for its first time in combat. But yeah, it's a basic design, but it's hard to go wrong with a 4 wheel drive aluminum framed mini racecar with a titanium wedge on the front..
I considered calling the robot Bouncing Betty but I thought the context of the name might be lost on most people who aren't familiar with Vietnam War Era weapons
If you want to see some better bots maybe check out some of my more recently videos like this one ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-puyQjctngl0.html
It seems like Shrapnel Mine’s design could be improved. I would have some forks that are not attached to the weapon, but end going up sharply, so pinning a bot with them would shove the bot upwards. Then it could have a traditional hammer saw, with the hinge right on the front. That way, Shrap. Mine’s forks wouldn’t have to turn downward when it attacks, a seeming weak point in the bot.
I didn't have any issues with the mechanics of the forks. Not really sure what you mean. I think the major issues I had were that the battery life was too short, drive torque was a bit lacking, and the front heavy weight distribution made it worse. I'm already working to address all those issues with a redesign.
@@JustCuzRobotics So, what happens when Shrap. Mine fires it’s saw? It hoists itself upward via its forks, because they’re hinged on the hammer arm, right? That just seems like a weakness that, no matter how slight, seems easily fixed, and you wouldn’t have to worry about being vulnerable for that split second that it does that hoisting. So, if your design requires pushing another bot into the wall anyway, why not just shape the forks so that they turn the opponent over upon pushing them into the wall? And on top of that, why not give it a Tantrum-styled puncher to make it easier to get to the bottom than with a hammer saw that has to arc upward? Just trying to expound an idea here.
"Why not give it a Tantrum style puncher" That's a lot easier said than done. I use an off the shelf servo for the arm motion which is very powerful and convenient for positional control but it's much slower than a puncher would normally be. I pretty much would have to re-engineer the entire weapon system. I don't think fixed forks will accomplish the same goal I have in mind for turning a bot onto its side either but I can play around with some ideas for that. Combining both doesn't seem too bad. I also don't think the hinging action makes the bot vulnerable since the AR500 forks are sticking out past the hinge points at all times even mid pivot. There isn't anything for the opponent to grab onto if they have a wide drum spinner, and if it's a narrow vertical spinner I will try to avoid a head on engagement. I generally will avoid pivoting the arm forward until I have the opponent in a good position.