(Part 2) Top products from r/battlebots

• The name of the game in combat robots is robustness and reliability. The forces that even very small robots undergo are mind-boggling, and any weak links can kill a robot.
  
  
• Work on skills like soldering, crimping, and so on. A loose wire connection can be just as devastating as a catastrophic structural failure.
  
  
• The link that Charles posted is very good. Here's another piece of great reading, for robots of all sizes. While some elements are very out of date, and the focus is quite a bit more big-bot, Grant's book still holds up as well, particularly the sections on fabrication skills if you're inexperienced in these areas.
  
  
• Study other robots. Learn "standards" for material thickness and such for a given weight class. Use the cubic scaling rule to convert elements from other classes. Try to intuit how their structural elements react against each other to build up strength. Take these lessons, and apply it to your own designs. Don't be afraid to generously borrow ideas. Ideas are fun but easy, it's quality and tiny details that make or break a robot.
  
  
• If you haven't already, pick up a CAD package and learn it. Autodesk Inventor and Solidworks are industry standard and free for students. If this doesn't apply to you, Autodesk Fusion is free to everybody, and is also a good choice. Learn how to use the material properties features to estimate weight. Not a necessity by any means, but it enhances the experience a ton, and in quite a few ways you wouldn't expect. Easier than you might expect as well.
  
  
• Speaking of which, pick up a good scale that works in fine increments. Check parts and the bot as a whole regularly. Unexpected things like wire weight will surprise you.
  
  
• Pick standard sizes for hardware and stick to them. You'll thank yourself later.
  
  
• Websites to familiarize yourself with: www.robotmarketplace.com, specific to robot combat. Lots of great parts for every aspect of a robot, you can basically get everything except raw building material from there. www.hobbyking.com, great source for lipo batteries, brushless motors and escs, and other miscellaneous electronic components. Some of their parts have a very real "china factor" associated with them, but there's a lot of good stuff as well. www.mcmaster.com, general purpose industrial supplier with amazing stock and shipping speed. Pretty much everything you'd ever want to build or make things can be found there, albeit often at a bit of a price premium. www.fingertechrobotics.com, a whole lot of components purpose-built for insect class combat.
  
  
• If you choose one component to splurge on, make it the radio. It can be shared by every bot you make, and a good radio with great reliability and extra features is useful at every level. My personal pick is the Frsky Taranis, but Spektrum and others make good stuff as well. Ditch the receiver that comes with it and pick up a compatible micro-receiver.
  
  
• Related, ditch any conceptions you may have about neat, nicely laid out, easy to work on electrical systems. That doesn't happen in combat robots.
  
  
• Some ballpark components to get you started for a (US) Antweight: 2x or 4x fingertech geared motors (silver spark, not gold). Fingertech TinyESC, or modified Vex Motor Controller 29. 2S or 3S LiPo battery, 250+ mAh. Fingertech hubs and foam wheels. Aim for ~8fps for a wedge, slower for a weaponed bot. UHMW or Polycarbonate for thick frame elements, Aluminum or titanium for armor plate.
  
  
• For testing, chuck the robot against a concrete wall, repeatedly. Don't be afraid to break it. Breaking it is how you learn to improve it.
  
  
• Bring spare parts to your competition, and design to make repairs as easy as possible.
  
  
• Finally, if you haven't already, I suggest joining here. Pretty much every serious builder in the sport hangs out there, and it's far and away the best place on the internet for in-depth technical discussion of combat robots.

We got second in the 6 lbs class at Bot Blast and had a ton of fun!

 

Videos of the fights:

Finals vs Plan F: https://youtu.be/xridxprporI

Semifinals vs Marauder: https://youtu.be/AUJgsL_dAjY

Third Round vs Plan F: https://youtu.be/2GYZhm7ABO4

Second Round vs Dynamo: https://youtu.be/odUNREOE6wo

First Round vs 6 lbs Rock: https://youtu.be/wIxcVdQMbhA

 

We learned a few good things too. First off the motors we used were meh for this class. Can push a beetle but not a mantis without teaming up. Perhaps we could overvolt them a tad... but I'm afraid they would blow up. Secondly we really need to glue the tires on, ha! I was super happy with our chassis, which we printed out of PLA (!) and was able to survive (mostly) a direct hit on the base from Plan F (!!!). Cuttingboard/UHMW wedges worked out awesomely. Scorpion Mini ESCs are pretty great too. Overall we are super happy with the results! We ordered the parts a couple weeks ago, designed the first rev of the chassis on Wednesday, bolted it together Thursday and redesigned it for rev 2 which we printed and assembled on Friday. If anyone is wondering, I used 1mm nozzles, 0.5mm layers, 2 layer top/bottom/perimeters, and 15% fast-honeycomb infill. Print time was about 7 hours on a gMax 1.5xt+ printer.

 

Overall cost for everything, minus transmitters & spares, was $152 per bot:

-ESC $45: https://www.botkits.com/collections/all-products/products/scorpion-mini-electronic-speed-control-esc

-Motors $28 total (400RPM): http://www.ebay.com/itm/DC-12V-2RPM-1000RPM-Powerful-High-Torque-Electric-Gear-Box-Motor-Speed-Reduction/351900958125

-Hubs $16: http://www.ebay.com/itm/12mm-Hex-Wheel-Adapter-for-6mm-Shaft-2-Pack/192198095398

-Wheels $11 (one pack per two bots): http://www.ebay.com/itm/US-4Pcs-RC-1-10-Short-Course-Truck-Tires-Wheel-12mm-Hex-For-TRAXXAS-SlASH-Car-/391591375091

-Battery $11: https://hobbyking.com/en_us/turnigy-nano-tech-1000mah-3s-45-90c-lipo-pack.html

-Cutting Board $15 (local store)

-Bolts $5 (home depot)

-Polycarbonate top (scrap)

-Speaker Wire (scrap)

-3D printing material $20 (one spool makes two bots): https://www.amazon.com/Polymaker-Polylactic-PolyMax-Spool-Diameter/dp/B00YXBNDHY/

 

If there is interest I can post the STL files for the chassis & motor mounts. Could be made even cheaper if you use a cheaper esc (found some on ebay but didn't know if they had BECs?) or cheaper hubs or cutting boards (these were from Sweden! ha, I liked the color...).

It was a joke. Chomp bounces around a lot like objects in a lava lamp, but at a faster pace. (I like Chomp's bouncing, by the way.)

I wonder what other bots would make a for a good lamp or other household objects? Warhead? A Tombstone model could make for a nice air fan. I want a Nightmare pizza cutter. Other TV objects have them.

Captain Shrederator mounted on the ceiling would make a nice lamp. A Smeeeeee toothbrush.

Have you ever played around with this? https://www.amazon.com/gp/aw/d/B004MFLU4Y/ref=mp_s_a_1_1?ie=UTF8&qid=1495313333&sr=8-1-spons&pi=AC_SX236_SY340_FMwebp_QL65&keywords=instamorph+moldable+plastic&psc=1

It's a plastic that turns clear, sticks to itself and gets a texture similar to silly putty when you put it in 55 degree Celsius water. Once it cools, the plastic hardens and is actually pretty durable. I made a cone shape like a party hat and smashed it with a hammer a few times and it flexed but sprung back into shape immediately. The plastic is remoldable if you just heat it back up. You could mold it into any shape or thickness you want, and it is actually pretty strong.

I don't see a weapon motor on your list. Do you already have one? Also, what's the servo for? If you're adding more to the kit, make sure you have the weight for it.


Now the Scorpion is overkill for an ant's drive system. I'd use 2 Vex29's instead for half the price. https://www.vexrobotics.com/276-2193.html The Vex's don't have a BEC, so you'll need one. My BEC of choice http://www.robotmarketplace.com/products/0-dys30053.html.


I'd use the money saved on the Vex's to get a FS-i6 transmitter/receiver https://www.amazon.com/GoolRC-Flysky-Transmitter-Helicopter-Receiver/dp/B013OHJ8JE/ref=sr_1_8?keywords=fs-i6&qid=1562437419&s=gateway&sr=8-8

It's a few bucks more. But all of mixing settings can be done on the screen, saving you the hassle of plugging it into a computer whenever you want to change something. The fs-i6 also allows you to store multiple profiles/receivers. So you can use the same transmitter for multiple robots.

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I'd assume you'd plug the servo directly into your receiver. In that case you'd need a dedicated BEC anyway because the Scorpion was designed to only power a receiver with its small current supply of .01 amps. Not enough to power a servo. The BEC has a current supply of 3 amps though which is plenty.


Let me know if you have any questions on any of this. I'd be happy to elaborate more. :)

If I was going to make a beetle crusher, I'd probably get something like this and strip as much weight from it as possible. I'm not sure it would be competitive- if you settled for just grappling and put the extra weight towards better drive it'd probably do better. But that's what I think it would take to get through the top armor of most beetles.

Here you goI'd still recommend ordering from the main site, they may have important information that's not detailed or is better formatted on their own site.

Hold on to the Nextrox motors, they could still be useful for lifting.

I still recommend the riobotz book. It gets to the point, has great information, and answers 99% of the questions most people ask, but don't take the time to actually research. If you read the book cover to cover, you'd have very few questions left. Plus, it's free to download, or you can buy a physical copy (like I did) from Amazon.

Amazon is actually pretty good for this kind of stuff: https://www.amazon.com/Molecular-Polyethylene-Standard-Tolerance-Thickness/dp/B00CPRDLAW/ref=sr_1_1?ie=UTF8&qid=1475004240&sr=8-1&keywords=uhmw

Sorry for the late response! I couldn't find this chat for some time and then I forgot. Here is what I wore for the 2018 season:

Jacket (gold) - https://www.amazon.com/Light-Up-Astrohoodie-Medium-Silver/dp/B00RC72EA8?ref_=w_bl_sl_ap_ap_web_8073005011&th=1

Shoes - https://www.amazon.com/gp/product/B01LX2VV2K/ref=oh_aui_detailpage_o06_s00?ie=UTF8&psc=1

Glasses - https://www.amazon.com/gp/product/B078GLGWHD/ref=oh_aui_detailpage_o06_s01?ie=UTF8&psc=1

Enjoy!

get yourself a quality soldering station because temperature control is actually extremely useful. There are cheaper alternatives to the hakko f888 but everywhere i've been this particular station eventually finds its way into every electronics room.

The SLA should be 12 volts. It's a standard size for lawnmowers.

https://www.amazon.com/UB1270-12V-7AH-SLA-BATTERY/dp/B0089N311K

Why do I get the feeling that you're trying to stick a car battery in that thing?

Somewhere he mentioned they came from amazon. Not sure if this is the exact one or not. Shoes similarly

https://www.amazon.com/Electric-Styles-Light-Astrohoodie-X-Large/dp/B00RC72DYU/ref=sr_1_51?keywords=light+up+hoodie&qid=1568341671&s=gateway&sr=8-51

https://www.amazon.com/Rust-Oleum-1937830-Metallic-Spray-Copper/dp/B000I1AXVW

Got ya fam. https://www.amazon.co.uk/Robot-Wars-Manual-Haynes-Manuals/dp/1785211862

I use these

https://www.amazon.co.uk/Bosch-2607010546-Multi-Construction-Drill-Pieces/dp/B001L1RAYQ

No pilot hole, tapping compound for coolant although you can do without and as slow a rotation as you can. Got one 10mm bit through 60mm thickness of hardox.

fwiw, i had a lot of radio interference problems on my heavyweight at robogames 2017, then i wrapped up all the high amp wires inside the bot with EMI tape and it seemed to fix it.