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Messages - zacodonnell

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Progress Reports / Re: Team Brain Damage
« on: October 12, 2020, 04:27:59 pm »
I recently realized all of the links I had to the old build albums are broken because Google took down picasa and then google + images (where they were migrated when picasa went down). Somehow I stumbled on this link the other day that includes an archive of my albums. Here are a couple of interesting / recent ones.

Jack Reacher Moto 2013:

Magneato Moto 2014 (cotton gin / coil drum variant)

Magneato Moto 2016 (smaller coil drum, 4wd initial attempt that flopped)

Magneato Moto 2017 (first electromagnetic clutch variant)

Shuttle Launch Bot Blast 2017 (screw powered flipper)

Tetanus FI 2011 (inline-AXI shell spinner with blade teeth)

Tetanus Moto 2012 (big hammer teeth)
editor's note: once I switched to the hammer teeth on this shell I think the robot won every fight it was in by KO except for one until the shell was far too bent to continue at the end of Moto 2014. This was maybe my most successful bot of all time.

Triggo FI 2014 (inline axi, too-tall shell that was much stronger than the one in Tetanus)

If people are looking for a bit of a historical fix on my machines that should take care of it


Progress Reports / Re: Team Cosmos
« on: September 29, 2020, 06:08:03 pm »
These kinds of projects are so cool. Your sensor description and trying to come up with a way for it to fit into a fighting robot reminded me of one of the earliest build reports I read after making my own robot:

People have been doing neat stuff in this space for a long time. I think the sportsman class opens the door up a little more for this kind of thing, even something like meccanum wheels, because you don't have to face the giant spinners. I look forward to more people taking advantage of the opportunity to branch out into this space more. I like the spinners as much or more than the next person, but for a totally different reason. All-out destruction is fun, exciting, and showy, but also expensive, time consuming, and short-lived. Sportsman bots with custom control systems, sensors, and interesting weapons are cool for the engineer part of my brain rather than the entertainer part. I bet you could find a use for some of these techniques and concepts in there.

I'm especially interested in the setup you have for monitoring and telemetry. I've done some basic Arduino serial writing to debug the systems on Magneato, but I never took it as far as you did with a real time output graph, interactive commands, etc.  I always seem to run out of time to do that kind of tuning (just like you) but have never been ambitious enough to aim that high yet.  The 3d printed enclosures around the components are a nice touch. It makes it way easier to leave the wire/connectors on there and pull it out of a tool box to use as an actual tool. I'd love to add telemetry, status, and performance logging stuff to my machines at some point. Even just the graphs that come from the Castle ESCs can be fascinating when tied to the video for a fight.

Progress Reports / Re: Team Thrasher / Sunny Robotics
« on: September 27, 2020, 08:07:59 pm »
This thread/video and some of Pete's work have got me excited again. I'm poking at some ideas for a sportsman concept I've been kicking around for a few years. I don't have the facilities to do much building right now but I am really enjoying the design work. Once I have it far enough along to decide if there is any chance of it actually working I'll post some of the thoughts and hopefully build reports here.

Thanks for the inspiration, and keep it up!


Progress Reports / Re: Team Cosmos
« on: September 27, 2020, 08:05:28 pm »
I just saw your video on Grond from AVC:

I very much enjoyed it. That kind of telemetry, tuning, and sensor work is exactly the kind of thing I'd love to have time to do with a version of my sportsman someday. Description videos that talk about the work and why you did it, where it might go from here, etc. are super interesting to me. I find myself with limited access to a shop at the moment, but videos like this and the gyro-walker bot posted here have got me excited about building again, even though the events are mostly drying up from COVID.

The reason I ran into the build report / video link at all was that I was doing some MOI calculations and my current computer setup doesn't have any form of 3D CAD so I was falling back to the old standby of the Cosmos calc. Thanks again for offering it!


Progress Reports / Re: Team Thrasher / Sunny Robotics
« on: August 31, 2020, 09:40:09 pm »
I know hardly anybody hangs out on these forums anymore, and that robot fighting in the public arena space has taken a pretty big hit with COVID, but it's posts like this that inspire me to get back to work on the crazy ideas I've been kicking around for a while.   I enjoyed your video, and watching you struggle to force the titanium into the shape you wanted brought back memories of similar woes I had with the .050 stuff I was using on Threecoil at one point. What a pain to work with...

Where are you planning to fight with this full combat 12? The drive that an event deadline provides is required for most people to go through the effort you are describing, but it seems like public events will be on hold for a while. A box that holds that monster isn't readily available for most.


Progress Reports / Re: Team Brain Damage
« on: March 01, 2020, 02:47:20 pm »
Pretty "meh" showing at Moto this year for Hyperpolarized.  The first fight was awesome, but one of the huge impacts damaged my weapon controller internally, which caused it to fail intermittently. This meant I thought it was working against Marathon, but it failed to start 5/6 tries.

I spent most of the day Saturday troubleshooting the intermittent controller issue, including doing some load testing in the pit without the shell that I think damaged my weapon belt. The weapon belt gave up the ghost in my third fight against Crmison Snow, but survived long enough for me to get the win.

My fourth fight was against Jamison with MegatRON. I can barely beat him on a good day, and with the issues I was having up to this point I doubted this was going to be one of those. I was right - further weapon belt issues caused the weapon to die after he bashed me into the wall for a minute or so and I tapped out.

In my last fight I faced Emulsifier. If the bot was working 100% I think I had a shot at him, though he had the thing super dialed in this year.  Unfortunately I only had the one spare belt, and I had just killed it against Megatron so no spin means no win for me. KO after the first hit when I landed upside down. 

I'm pretty sure the belt issues were because the drawing I used to replace that frame rail included the wrong spacing for the weapon motor. I fixed it manually last year by remaking the part, but apparently even though I thought I updated the drawing I had not. That meant extra slack (about .040" to short on the center distance!) and that meant dead belts when I smack stuff hard enough. Naturally my spin tests at home couldn't show that problem. I'll need a more thorough testing mechanism.

Videos are here:

I think I basically have to fix a little damage from the Emulsifier hit and maybe grind/rework the teeth a little from accumulated wear, and fix the belt thing and I'm back in business. Alas, another year to wait...


Progress Reports / Re: Team Brain Damage
« on: February 11, 2020, 11:37:34 pm »
I got the bot all wrapped up today.

I ended up raising the shell 1/8". I realized that something was wrong with my thinking. I originally thought because the idler was getting murdered at Moto last year that the drag issue was caused by friction there. After thinking a little longer and watching some of my test videos I realized that the drag issue can't be from friction between the shell and the base... the drag is the wrong direction for that.  If the shell was hitting the base it would be slowly seeking the direction the shell is going. If it was just counter-inertia from moving the shell it would stop if I turn off the weapon motor.  My best guess for what was left was the shell hitting the floor and pushing the bot the opposite of the direction of the shell, because it's really pushing the floor in the direction of the shell.  So I raised the shell 1/8" and... way less drag, way better handling.  It's kinda dumb how long it took me to think of it.  The roller setup was always designed to be shim-able if I needed to, so I just installed the shim under the roller and removed the one on top of the shell.

I also made a lighter weight baseplate that will allow me to have heavier bolt-on teeth if necessary, and function as a backup if needed as well.   Tomorrow will be packing and cleanup, as well as volleyball and catching up on some chores I've been neglecting pretty hard.

Hope everybody else is coming along too!

Progress Reports / Re: Team Brain Damage
« on: February 10, 2020, 07:02:13 am »
Oops, the app should be available in Canada now.  I originally just listed it in the US so that I didn't have to spend a bunch of time dealing with GDPR stuff, but of course there is a large Canadian Contingent invading from the north as well.

The solid UHMW roller with the aluminum hub continues to be a good solution. I did another test with a harder powered roller yesterday to see if it would slip instead of burning up if there was more resistance spinning up the shell than expected. I think this is what cost me the last two fights at moto last year. The first time I think one of the top screws dropped through the shell and bridged the gap with a hole in the mid plate, and the second time I think it was the scum of the first roller getting bound up in the crappy idler. Now I've fixed the idler and the top plate screw issue, but if something does bind up I'd rather the wheel slip than just get completely burned up.

I made spare rollers, teeth, drive controllers, weapon controller, and a weapon motor last night. I also started the painting train. All that's left is final assembly, weight check, and packing


Progress Reports / Re: Team Brain Damage
« on: February 09, 2020, 12:55:12 pm »
I should also point out that when the list changes you won't get more than one notification. If you're watching a whole army of bots (and you will be with your crew...) then it's likely multiples will be on the list at a time. When that happens you'll get notified about whatever the soonest fight is with a "+ 2 more" added to the message to say there are two others you subscribed to also on the list. In any case, when the notification comes in I'm expecting you to check the list to see what the deal is - the notification is just so it doesn't surprise you.

Basically I've been having one of my crew be in charge of watching the list for years. Now I don't have to - there's a robot in Iowa doing it for me.  It only checks every minute but that should be faster than a person was going to in most cases anyway. When we get to the real show I'll disable the simulation and start watching the real list instead.


Progress Reports / Re: Team Brain Damage
« on: February 09, 2020, 12:49:59 pm »
Any Time the Bot Moves is the feature you want. You'll get a message if the position for that bot changes on the list. So if it arrives at the bottom you'll get a message, then every time the fight list is published it checks to see if the position changed. Sometimes we just add more fights below it so you won't get a message, but if any fights ahead of it get remove (like the fight happens, somebody postpones, etc) the position will change and it will tell you. 

I struggled with making the names concise and also useful. I'll have to think some more. Basically "when up soon" is for people who want to watch the fight like family and friends (or really cool bots for other builders). "Any time it moves" is for your bots, so you know you will be ready for the fight.

Feel free to provide any other feedback you have. Right now I know it's annoying that the android "back" button doesn't really do anything. It's on the list... but it's probably not happening before the event unless time magically appears :)


Progress Reports / Re: Team Brain Damage
« on: February 09, 2020, 08:05:36 am »
I didn't work on the bot at all yesterday. Still to do:
Spare weapon rollers
Spare top plate
Some more testing

I'll try to do some of that today.  Instead of working in the shop like I should have, I tried to wrap up the project I mentioned the other day on here. I have created a phone app (currently only available on Android) that should help builders know when they are on the list and be able to look at the bot details for registered bots. It will also be useful for the friends/family of builders so they can tune in to the stream when the time is right.

For the moment it is in beta mode (anybody with the link). and there is also a web site that doesn't have all the native app goodies but still allows some of the interactions. I expect to publish it on the android store before motorama but not tell non-builders.  It still probably has bugs as I haven't tested it super-thoroughly.

At the moment it is running a fake simulation of Moto 2020. The list updates every minute or so and you can subscribe to bots and it will send you notifications. Humphrey Hugabear is a frequent bot so you can see the notification flow easiest by using that as an example. The Watch Now link points to an old youtube capture. When I have the live stream link I'll update it to point to the right place.

Eventually I'd like to roll it out to IOS as well, and allow the live stream and audience in the stands to use it. Long term I'd love to allow people to upvote fights they like and stuff like that but I don't have any more time before moto. For now, give it a shot and see what you think. I'm currently rolling out a fix for the wrong bots showing up the first time you "explore". It takes a while to propagate through Google's app servers.

Android Beta:


Progress Reports / Re: Team Brain Damage
« on: February 06, 2020, 06:44:11 pm »
After some minor adjustments I'm happy with where the solid UHMW roller landed. I don't have the video on hand just yet, but it is much smoother than before. I think the underlying issue is a slight inaccuracy in the flatness of the shell top. When I rotate it by hand I can see the center of the shell going up and down a little, maybe a bit more than 1/16". At the speeds I'm dealing with that means a lot of vibration

I've got some spares to make, painting, etc but I should be in business next weekend.


Progress Reports / Re: Team Brain Damage
« on: February 01, 2020, 04:41:14 pm »
Yep, I'm coming to realize that. Thanks for the confirmation. Unfortunately it's designed as a 2" diameter part and I only have 1.75" UHMW in stock. I ordered some 2" material (and 2.75" so I can make whatever I need in the future!). It should be here Tuesday.

In the mean time I got the idler hub made, top plate installed and verified, bearing mount installed, and top teeth installed. It just barely makes weight with everything, but I have a double stack of retaining plates on the center post that I can use as ballast if the scale is not feeling forgiving.

I've got some other stuff going this weekend, but will try to get the idler and some spare stuff made up this week.



Progress Reports / Re: Team Brain Damage
« on: January 30, 2020, 10:36:20 pm »
I *could* make them the exact same, and in fact I have two duplicates for the powered roller so I can swap in two minutes instead of disassembling the hub assembly. It's like a speed reloader for a revolver. Actually it kinda looks like one too since it has six standoffs screwed into one side of the hub.

The thing is, the shaft setup for the idler one is more compact because the bearings are inside the wheels with a dead shaft instead of a live shaft with bearings outside. I am totally out of space. A hub for the idler could be a lot simpler than the powered one because I could skip the keyway, counterbore, and standoffs. Just glueing the roller to the hub since it shouldn't need to be replaced would be fine. I may just go that route if the banebots wheels don't work out. It's basically the same amount of work as making a hub for a colson that fits the bearings I have.

Tonight I got started on replacing the center post. I the OD, ID, and retaining nub on the back finished. I'm happy with how they turned out. I still need to drill the bolt pattern and add the retaining screw like I did with the other one. Then I have to install it in the bot which will require unbolting the weapon motor. That's an unfortunate artifact of the design, and I could have skipped one of the six retaining bolts to avoid it. If I expected to do it more often I probably would have but the extra strength in that part was worth the extra headache. I wasn't even planning to have a spare originally but the tolerances on the center bearing are just too bad to keep what I have.



Progress Reports / Re: Team Brain Damage
« on: January 29, 2020, 10:34:55 pm »
I tried small UHMW last year and it annihilated the bore. With the bigger space I might be able to make something work but it needs to reliably retain the bearings too so having a metal hub with a tight press fit is important. If I'm gonna go that far I'll just make it out of the same as the main roller and be done


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