And We’re Back In Business! An Equals Zero Return to Form, or So I Hope

After much ado about a whole lot of things, this site is now at least in a working state where all my information is accessible… even if it doesn’t look quite all aligned, all my plugins are missing, things might not be in the right place, and so on. This website is still a van, just a newer one.

By the way, I noticed all of your 63 emails asking what happened to the site! Hell, I didn’t know people still had the patience to read blog posts in this era of Youtube subscriptions and TikTok follows. A lot of valuable info resides here, so I definitely had the incentive to get everything running again, just a matter of willpower (This will be a theme for this post…)

So I had to relearn a lot of “Internet Stuff” since the last real revamp of the site from 2009. The biggest challenge ended up being re-importing the database which actually dates back to 2007 (the earliest posts on this site now), which is why this site was a potato dealership for a few days.

First, I had trouble importing the 200-something megabyte database dump, and it took several retries in different browsers and different times of day. Not only that, but fancy hax0r Charles of 2006 named all of his WordPress databases fancy names, so the new WordPress install didn’t know ass from teakettle. Next, because all of my domains are now unified on one hosting account (Equals Zero Designs and Marconi Motors), I had to connect all the subdomain dots. I’ve also never seen cPanel in my life, despite it being available back then also – I did pretty much all of the setup and back end work through FTP and phpMyAdmin directly, so there was just button clicking to learn.

I’m still going from theme to theme, so the immediate appearance of this site might change in the next few days. I’m trying to keep it a dark and easily browsable theme. The one I have as of 1/11 also has a banner image like the previous rendition, but I haven’t reuploaded those yet. It also has a bad habit of displaying the past few posts all together making the front page infinitely long, and I have yet to find the setting for breaking it up into previews only! I also still need to get used to the visual editor that WordPress ships with now – I’m not a fan of it so far, since it’s more of a walled garden experience and it’s a little harder to use my historic file and photo structure. But alas, welcome to the Internet of Today.

Anyways, after all of my makeshift database adminning, here we are again – I’m sure I’ll make a post like this again in another 11-14 years. All of the old posts should be there, but I have not (and will not) check them for layout or importation mishaps, as I consider those pretty much static archives at this point. Look, my van posts are here for my own reference and that’s all that matters.

So! Onto the new content. Besides now the Summer of Ven and Overhaul 3 Design & Build series posts I need to backfill, there’s some new stuff in the pipeline because I will somehow always find new vans to work on. I’ll just add this to the “List of Things I Still Have To Blog About”. Here’s the short story of, I dunno, since late September or thereabouts.

dromes

You know what? I miss having my own drone. I keep working on everyone else’s drones, but I haven’t had one truly of my own since all the way back in the Tinycopter days. Back then, I had the audacity to code my own flight controller, but these days most of my work is integrating Arducopter and PX4, flight controller firmwares that are….. less haphazardly put together. With safety and what not. Somehow I’ve built dromes for many entities since then, including KIWI of course, and my current place of employ, but what measure is a drome engineer if he doesn’t have any of his own?

And so I went to pray at the Altar of Lord Bezos and visited the Oracle of Jack Ma. You know the adage “Buy right, or buy twice”? My take it on it is “Why buy right when you can buy very specifically wrong and buy a lot?” It’s like getting a 0 on the SAT, since you have to answer every question incorrectly and can’t just shotgun it at random. You have to specifically know what not to buy, so your pile of parts has a minimal chance of cooperating, maximizing your chances of failure but forcing an exploration of the tradespace into places no sensible engineer would touch. Long time readers will understand this is my M.O. for everything – I know what to do, so why do it when you can try something dumb since nothing matters and we’re all going to hell anyway?

As such, crafted out of a tote of deprecated KIWI parts and my robot electronics bins, helped along by some deconstructed Seg-baby packs dating back to 2015 (RIP seg-thing), and with the blessing of the lowest-priced drone parts AliExpress could provide, I present Trashcopter:

The least fine drome that money can maybe buy!

This thing is…. a drone. There’s nothing special about it. I just wanted a beater drone to fly when I felt like it. It works fine, I went through the usual setup and tuning and fine craftsmanship associated with putting a kit drone together, and it is still in one piece as of this writing. It can fly autonomous missions, take off and land itself, follow terrains and avoid (large, visible to IR light) objects, and do a barrel roll in mid-air once. (Okay, it was for a brief couple of hours not in one piece). It ain’t a Skydio II, it’s basically a potato someone threw very hard, very controllably.

I explored the sub-basement steam room of drone parts on this build by purposefully trying to sort by price lowest and free shipping. What I found is an entire under the fallen log ecosystem of used drone parts, selling motors and ESCs and subassemblies for $1-$5 apiece. As expected, I now own like 50 motors pulled from XiaoMi drones, and the ESCs that go with them.

The frame is the cheapest, most terrible DJI FlameWheel knockoff I could find. The finish is so ratchet that I had to deburr everything before using it (and correct some of the heatset insert work, and open up some of the PCB chassis plate holes…), but I also now have 6 frames worth of questionably molded nylon arms. I mean you should see the sink marks on these arms. What I’m saying is, I can build as many terrible drones as I feel like now, for less than the cost of getting parts stateside for one single functional unit.

I furthermore went shopping for the crappiest radio I could find – the “Can I find something even cheaper than the 4 channel HobbyKing 2.4Ghz radio?” and that result is sitting next to it, the “MicroZone MC6” series. Like Trashcopter, it is “An Radio”. It has all the right shapes and tchotchkes in the right places, and Doesn’t Not Work. Hell, it’s even 6 (secretly 7) channels.

The build report for this guy will expound more on the process I took to get the parts, exploring some of the parts themselves including taking apart the cheapo radio, and just generally show the setup of a modern-day Pixhawk and Arducopter based multirotor from end to end for posterity.

But that’s not all.

I hinted in the original Robot Trap House post that I had unfinished business in the sector of Very Lörge Dromes that I still wanted to explore and develop, but which wasn’t relevant to the KIWI business needs at the time. One of these in particular is my strong belief that the “One motor per prop” multirotor architecture doesn’t really scale to large, flying van levels. You CAN make it work, and many companies have, often at great expense of either buying or developing cutting-edge custom motors and materials for airframe and propellers.

That clashed with my general philosophy of “Don’t custom unless you want to make a project out of the custom thing”, and consequently the direction of KIWI, where every aerospace engineer we tried to hire dropped to the floor and foamed at the mouth as soon as they witnessed our extremely BattleBot-like building approach: COTS and easy sheet metal and extrusion weldments.

The magic sauce to me when it comes to electromechanical hardware startups lies not in exotic in-house cooked and served materials and genetically-evolved one-piece structures, but getting out into the field with a working, reliable robot in front of the customer and a practiced means of getting there many times. I’m a bad CTO – I don’t like technology.

So how do I aim to demonstrate an alternative? Well, I reached just a little bit back into history, like a few years, into the domain of the Variable-Pitch Multirotor. Also called “Heliquads” or “Collective Pitch Multirotors”, they trade a little bit of mechanical complexity (The collective-only rotor head) for, in my soon-qualifiable opinion, a broad increase in the maneuverability space and control bandwidth.

My still-in-progress entry into this design tradespace will be what I affectionately named “Wigglecopter“:

Yes, that is my dinner table. No, nobody ever comes over.

In short, for a minor increase in thrust for vehicle attitude correction, a conventional multirotor has to spin up and down the propellers. Your torque to inertia proportions really, REALLY matter. Everything needs to be as light as have as little MOI as possible, and your motors need to be as torque dense as possible, to get a high enough control loop bandwidth to keep the vehicle stable.

Conversely a VPM/CPM can issue corrections by adjusting the pitch of its propellers. Single-degree movements will induce variations in thrust corresponding to possibly hundreds of RPM of motor speed. There is a lot of literature in the advanced aerospace controls scene pertaining to these, and I’ll collate and dive into a few papers I’ve taken a liking to in its build reports.

I actually tried to buy one of these, as they were sold for a while in the Early Teenies by a few hobby vendors with models such as the HobbyKing Reaper 450, WLToys V383, and the CJY Stinger 500. They’ve pretty much all died out, so instead of hunting around for used or new-old ones, I decided the mechanical problem was simple enough to just put together and get the point across.

If you look closely, Wigglecopter is just made from the same pile of garbage that Trashcopter emerged from. I just ordered a few DJI F450 quad frame cards from Amazon to make it a quad, and had to gently re-engineer the motors to accept the collective pitch mechanism and propellers. I’m going to put some more legitimate gear into this thing from the flight control and sensing side, as I’d like for it to be a development platform.

Notice that it still does have four independent motors? Well, you can still do that with a CPM, provided you now keep the motor speed constant so your thrust output is not a multivariate surface of sagging motor speed and flexible propeller blades…. just one of them, as much as possible. I decided trying to make a serpentine belt drive was just going too hard the first time out, and will just bypass this issue with inertia rings pressed onto the motors if need be, and with the ESCs set to speed govern. We’ll see what it does!

My LTE plan for Wigglecopter is to finish and validate it, then start getting larger and larger. I’m going to need to modify the firmware a little for myself, as I would like to make a collective-pitch Hex and Octo down the line. Wigglecopter itself should be all done and ready this spring, and its bloodline is completely unplanned except for daydreaming of lifting Kei vans in the air.

Overhaul 1 Restoration

A very exciting new development in my life is that I now have Overhaul 1 in my possession again. In November, I made a speedrun up to Boston to collect the remainder of the several hundred pounds of life I left in the ol’ vape shop. At this point, I was able to extract Overhaul 1 from its dormant state. For the past few weeks, I’ve been going through it (there’s not much, mind you) and getting it back in running order.

There’s no intention of putting it back in battle except a few token matches with Sadbot, Overhaul 2, and Overhaul 3. Yes, somehow I will soon have four operational heavyweight Battlebots. It’s like vans, they just keep spawning. Everyone I know agrees that it would be incredibly funny if Overhaul 3 loses to every preceding generation of Overhaul. I mean, it’s never won against Sadbot, so this is a distinct possibility.

I designed up a retrofit for the drive motors on the shuffle pods, implementing a design idea we should have done but didn’t have the time to execute. Right now, the electronics bay is a small plastic tote bungee-corded to the frame, but I’m going to design up an integrated battery case and electronics deck so I can close it up. It won’t be as (unnecessarily) fast as it was before, as as a bot I’ll probably reserve for demos and showings only, doesn’t need to be anyway.

I also had to straighten out a lot of bent parts. You know what – my adventures in Big Chuck’s Auto Body came home to roost. There were a lot of fun rednecky processes involved in straightening the welded unibody-ish frame and the pointy plow.

So, hopefully Overhaul 1’s “Rebuild Report” will just read like one of my many other hundreds of “I fixed this stupid thing that broke because I was stupid to begin with” titles.

all of the ven are piles

As of right now, my entire treasure fleet is in disarray. While everybody runs and drives, I wouldn’t characterize any as “particularly competent”. It’s winter, and they’re not in danger of being towed or fined for the first time, so in a way this little return to form with me building robots again has been at the expense of the ven.

Why are they so derelict? Well, I think in part it’s due to me continually throwing them up and down mountains.

Now that I’m only about 3 to 4 hours from the very vannable mountain roads of northern Georgia and the North Carolina/Tennessee border, it means I go…

I’m the width of the road, I’m the width of the road, I’m the wiGET BACK IN YOUR LANE NOW

…all…

Look at that inside-front liftoff. Rear sway bar time?

…the time

I do think at least once every month so far I’ve ended up somewhere in the area with vehicles nobody expects to ever witness in general, much less on a mountain. I’ve gone with groups (typically composed of SPROTS CARS) and when I damn felt like it.

The downside is obviously that the exercise is very strenuous for tired old ven. Here’s the lockout tag captions for everything as it stands:

Mikuvan

  • The entire exhaust path from the axle-clearing bend back fell off in late May when I was on the Tail of the Dragon. Yes, fell off. As in the person behind me had to dodge it. Straight-piping 3 hours home was hilarious, albeit dissatisfactory for hearing longevity. I replaced the exhaust in my first fully welded/fabricated custom exhaust job in June. In fact, look at it ratchet strapped to the roof rack above, as a victory trophy.
  • Complete front brake caliper and rotor replacement in November – it’s had one mildly dragging caliper for a while, and it was tolerable until some amount of smashing on the mountain caused it to seize even more.
  • Now it’s slowly leaking brake fluid from the master cylinder/booster assembly – while it stops fine, the fluid loss is gradual and both faster than I’m comfortable with and want to deal with the mess.
  • The power steering pump is now making absolutely terrific sounds and leaking at the shaft seal, so it’ll be on the chopping block for replacement.
  • There is a cable harness that the cruise control computer intercepts the transmission overdrive solenoid with which has failing pins. This has manifested in sporadic loss of 4th gear, meaning I’m either going 55mph tops or absolutely revving it flat out to hit 70. A kick or tug on the harness will often resolve it – I’ve tried various methods of biasing and restraining the connector pigtail over the past year or so, but outright repair/bypass is now a necessity because it’s getting too annoying.

Vantruck

  • Developed either a misfire or bad exhaust leak from the right cylinder bank, so while it will drive fine, it sure sounds like an old rattly diesel when it isn’t one (yet…). I’ll need to do a full heuristic debug before commenting on it more – it got worse lately as the weather cooled down.
  • It’s recently began emitting blue smoke out the exhaust intermittently. I’d attribute this solely to something like worn/crispy valve stem seals or sticky piston rings, but what was more worrisome is that the oil pressure gauge began to not register pressure. Now, in this era of Ferd, the oil pressure gauge appears to be a fake one – really an on-off scenario. I haven’t correlated the two symptoms by physically measuring the oil pressure yet, and really cannot say I’ve paid enough attention to said pressure gauge in months past for it to even have been symptomatic of anything. It could be a coincidence. Either way, out of an abundance of caution, I haven’t been driving Vantruck around the past few weeks.
  • Rear drum brakes have something going on, probably just excessive wear. If I set the parking brake, the rear brakes will drag for a while after releasing them. If I brake in reverse, then drive and brake forward, there’s a palpable clunk as something with just a bit too much slop pops back into position. Sounds straightforward, just willpower-limited for dissection.

Spool Bus

  • It came with a diesel leak around the left bank of injectors – old and crispy return line fittings, and the cold weather has made it worse to the point where I’d prefer not to drive it. Less due to the fire hazard and more because it stanks of diesel, costs me money by leaking it out, and is rude to others for leaving dribbles on the road. Willpower-limited repair, as I have the fittings and hoses sitting in it right this minute.
  • Thrashing about the mountains has caused a power steering system leak. I haven’t dug into it to find out where from, but it’s actually not from the gearbox itself this time (a known failure mode of many a Ford truck), so it’s probably a stiff hose or loose fitting. In fact, I had to abandon a day on US Route 129 a few months ago because the power steering leak became dramatically worse all of a sudden, a small puddle per power cycle. Luckily, the system was filled with transmission fluid and I had a quart to keep topping it off on the trip home.

You notice it’s all turning and stopping related problems, more or less? Well, in order to not fly off the side of a mountain, it’s imperative that you be able to turn and slow down. Vans, while imperfect at this, can be coerced into doing so somewhat gracefully, but they’ll only put up with it for so long.

Oh, yeah, where’s Murdervan? Spoiler alert – I sold it back in September after shoring everything up nicely and writing a Facebook ad that, in light of current events might get me Investigated. It was sold locally in-town to someone who seemed enthusiastic and knowledgeable of old Ferd diesel trucks, and will join a small business fleet that does urban gardening and landscaping work. A very fitting end to its brief story with me, as it was always just too normal for my misfits. I’m sure I’ll see it around the city more!

So there’s also a lot of Ven to write up, besides the Summer of Ven series itself. I better get used to loving this keyboard and its probable timely successor once the keys start falling off.

Cute little robots

A few weeks ago, I was skulking around knick knack stores in the farthest reaches of Georgia (my latest habit, finally checking out all those antique and flea markets I keep blasting by on the way back and forth from the Smokies and Blue Ridge). A lot of these stores have vintage tools and hardware, which I enjoy perusing. However, at one of them, I found this little guy:

That, if you’re not familiar, is a Dr. Inferno Jr. Well, not really. It’s a Tomy Omnibot, a little robot toy of the 1980s that was probably pretty badass for its time, being programmable via cassette tape and all.

Needless to say, I made off with it because hey, it has some relation to BattleBots history as well as the history of programmable smart toys. It was in good physical condition, though the proprietors said they couldn’t locate the remote control at the time but would keep mining their stocks for it.

Without the OEM remote, it seems rather static based on my research, and so I decided to perform a unique restomod. I’d do a mechanical repair and restoration to get it in driveable first, but I had an element I wanted to add.

That is an old Futaba T4NL Conquest I got for free at some Swapfest at MIT many moons ago, and have just had sitting in one of my Electronics Mystery Abyss totes since. What better to control your 80s robot with than an 80s radio!

What you can’t see from the outside is the MicroZone MC6 transmitter that I organ-swapped into the T4NL. Yup, I done did it – a restomod of the transmitter with a modern day, albeit potato, 2.4G computer radio. This was a fun adventure, and I think I approached it in a unique (but harder) way than just tapping the PPM summation point and feeding it into a 2.4G radio module. I fully embedded the MC6 using the original Futaba gimbals, added the MC6 servo reverser switches to the back side, and wired in new switches to turn the 4 channel T4NL into a full fledged 7-channel radio.

And of course, this photo of my 80s robot that I drove around with my 80s R/C radio was taken at a car show I took my 80s van to. This, as I called it on the Facesphere, is #Radwoodbait for whenever those shows come back up.

I’d definitely love to write up the whole restomod of both the Omnibot and the Conquest T4NL radio, because it was just a fun distraction project over the holidays when everything was closed and I didn’t feel like going outside.

Remember, even while I’ve refrained from fixing this web-van (HEHEHE WEBVAN) up to post content, I’ve been taking my usual excessive amount of photos of every step or interesting happening. The content exists, I just have to find the willpower to write it up – and I hope finally having the damn site operational again will motivate it.

Also, I have so much to remember what I named “Potato”…starting with the title of this site. I’ll take care of it soon, I promise.

robots

The Long, Cold Winter of No Posting Ends: Awaken the sadbot2019

Is this thing still running?

Needless to say I am a little less than proud of the longest post drought this site has ever seen. I’m still alive! Just preoccupied largely with getting the company product technology to a stage where I can at least be assured the tunnel will end eventually, even if I haven’t seen the light yet. Along with this gradual better-scoping of product tasks, it’s taken me a while to get used to not just working on dumb projects all the time in big blocks of work, but learning how to divide up tasks and think about their dependencies more, such that I can pick stuff up and drop it back off easily. I brought this up a bit in the preamble of the Great Mikuvan Engine Rebuild Scandal of yesteryear. Whatever, it just means hopefully I can get back to working on stuff, but until the day I exit the company and become a full time bad idea investor, the pace will inevitably be slower.

I believe the real world calls this “Adulting”.

Anyhow, adulting is dumb and robots are cool. Let’s revisit Sadbot, which was left kind of functioning last year some time before I sold the pokey dingle to a west coast team. Then, incrementally more parts started coming out of it until there wasn’t much left but Overhaul 1’s drive system and a steel box. With the coming of BattleBots season 4, I figured I had to at least work on something, and I should probably consider repairing my wreckage instead of creating new wreckage.

Oh, if you notice the timing of this post – I’m clearly not competing in Season 4 with Overhaul.


I mean, if I didn’t even clean the barbeque out of it yet….

Ultimately I didn’t think I could muster up the time and resources to do the bot justice, and enough of the team has split off to get real jobs (among other things, I mean) that i would have had to rally up a new crew. So, perhaps next year, and maybe it’s a blessing in disguise because now I’ll work on Sadbot out of FOMO and remorse, perhaps discovering something new about Overhaul in the mean time!

Next season, though. I promise I’ll be Bach.

So I set out to change up Sadbot in a fashion that would reflect the mods I want to make to Overhaul for next season. That in detail is itself an entire blog post for when Overhaul is modified for #Season5 one day, but in short…

  • Change the drivetrain to the 80mm “melon” motors – Sadbot being a single motor per side, it will 100% reflect the drivetrain setup I want Overhaul to have in the future, as in my post-season assessment the dual motor setup has not been as reliable as I wanted.
  • Using this opportunity to make sure the 12FET Brushless Rages weren’t actually trash, but were not utilized right the first time out. I had some more testing and changes I wanted to make after Season 3 that I hadn’t gotten around t
  • Finally doing the tractor pull contest between Sadbot and Overhaul which never happened. While the bot had “more” traction than Season 2, it wasn’t that much more, just more linear and predictable. I want more, something which I suspect is beyond the capabilities of my current bot architecture.

The first step is putting the damn thing together again. To do that, as usual, it has to come apart more first!

To retrofit the 80mm outrunners, I had to re-introduce Overhaul 1’s intermediate drive gear. The previous motors in Sadbot were 59mm SK3 outrunners running into Banebots P80 gearboxes, so the motors were already geared down and only needed the center sprocket.

To get the ratio I needed using a gearbox would have made the assembly too long to fit into the frame, so I needed to directly attach the motors to the face, needing the extra ~3:1 the intermediate gear provides.

I machined these gear-sprocket combos late last year. They’re waterjet-cut 12DP gears that are pinned into the sprocket face such that the assembly rotates on a dead shaft (pictured mounted in its former home). These were virtually identical to Overhaul 1’s (which were long disassembled or I’d have used them again!) but a different ratio.

New socket cap screw holes sunk into the drive plates – now featuring THREE bolt patterns! P80, 3″ Ampflow/Magmotor, and 80mm C-series outrunner.

Modules taken apart, cleaned, regreased/re-threadlocked, and reassembled.

At this point, the ‘skateboard’ of the bot weighed 163 pounds without batteries or the controller housing. This began my contemplation for bringing back the pokey dingle. I’d sold it because I didn’t like the design any more and someone else was going to incorporate it into another bot, so what better way to force me to start over?

Originally, Sadbot was going to be 220lb (nationwide Heavyweight class) without the pokey dingle, functioning only as a pusher/brick bot, and 250 pounds with it in order to simulate a BattleBots practice opponent. I was, after this weigh-in, now convinced I could make it close to 220lb even with a weapon, which would let it compete in the rising amount of “Heavyweight Sportsman’s” events around the country. Or at least I’d get it close enough that the laid-back nature of these events would make them take it anyway!

Next up, assembling the control deck. These were parts also designed and cut out last year – a basic polycarbonate tabbed box and nutstrips to make a second floor. Batteries will be mounted on the first level, and the aluminum plate mezzanine will house the brushless Ragebridges.

Originally, I wanted to use the Overhaul 1 batteries after being decomposed from the modules. However, they aged poorly and the cells have high internal resistance now, so I put together some of the Overhaul Season 3 batteries (Hobbyking Graphene bricks) instead. I greatly enjoyed how these worked in Overhaul, and while it packed four, I think two would have been plenty. Well, it’s time to test that!

The batteries are secured on the bottom with a few acres of Dual-Lock – think gender neutral Velcro for the woke Millennial – and then pressure-retained downwards by the 1/8″ aluminum plate with the adhesive-back foam rubber pad.

I forgot how easy wiring a 3-motor robot was. That’s it! This is the whole wiring harness, minus the battery-side mating connectors.

The rest of the wiring was built up over basically one evening. I had two leftover Whyachi Switches, one which I’ll set aside for the New Pokey Dingle weapon and the other for the drive. This keeps the activation process similar to what’s expected for BattleBots and also just allows me to test one system or the other.

And that’s all, really! This build was quite short and pleasant, occurring over several nights in about a week and some. Sadbot at this point weighed just under 180 pounds, which only left me around 40 for the entirety of the New Pokey Dingle. Difficult, and I decided at this point that the 220lb max goal was probably not that important, but I’ll give it a try.

 

I knew the parts I wanted to use already – an Overhaul lift gearbox (Banebots BB220 16:1 and SK3 59mm 149kv motor), enough reduction to get to about 180:1 which is the same ratio as Overhaul, and that the end effector should still be the Harbor Freight “manual slide log splitter” / toe destroyer. Furthermore, last time I permanently welded the tool to the output shaft, but this time I intended to make the output a socket to potentially make interchangeable ends.

I started flowing plates around some initial component placements. The output sprocket was only going to be able to get so big, so I fixed that first (48 tooth) and gave it a position that had some clearance to the electronics box, some clearance to the ground, but high enough to allow the motor to tuck underneath with some semblance of an intermediate stage. The width was fixed by choice at “Between the Melons” – one of the things I didn’t like about the last Pokey Dingle was how wide it was for what it did, and I had some ideas which involved moving the sprockets around to make the while thing narrower.

Here’s roughly what that looks like. The chain stages are very short and all overlap. Technically, I could have made this just open gearing, but chain drive is more available and serviceable – all of these sprockets, save for the output, are off the shelf parts.

I was contemplating how to make interchangeable “manipulator” sockets compact enough to fit in the confines of the side plates. I played with a couple of ideas including welded machined parts, making it a live shaft again (but with a socket tube welded to the shaft, and so on. All of these ideas turned out to be either too wide or, after a moment of …. brilliance? too tacky and complex.

Why not just weld the damn square tube to the plate sprocket, using the bushing as a locating feature!? The  wall thickness of the tube certainly permitted any inserted attachments to not come in contact with the drive chain, so that was really all.

I also utilized a chain tensioning approach which I remembered, but couldn’t place where I learned it from. Typically with a slotted mounting system you’d place the slots parallel to the direction of tension needed, e.g. slide the motor away from the shaft perpendicularly if you need to adjust the chain/belt spacing.

However, this arrangement doesn’t resist the normal forces that chain tension plus torque puts on the sprockets, which tends to force them together and loosen things up. At least, not all that well unless you had massive fasteners. Instead, I angled the bearing mounting slots at 30 degrees from the perpendicular to the axis joining the sprocket centers. This means I move the sprocket more “up and down” relative to the other one, but there’s that 0.5x component introduced by the 30 degree inclination which adjust the actual tension, and also reduces the effect of the tension “attractive force” immensely.

The downside? I have to have two chain pitches (well, sqrt(3) / 2, so basically 2) of vertical free movement in the chain to gain that horizontal spacing. That’s not all that much when considered, so only a little geometric squishing was needed to get space for everything.

Initial positioning in the bot  yielded some more Geometric Squishing to get the parts to all clear. I went out of my way to make things actually parametric and geometrically related instead of hard-coding dimensions, enabling some click-and-drag placement.

The final assembly by itself modeled with shaft and bearings for a realistic weight. It looks like this thing will weigh a little over 40 pounds after all. I added some cutouts to remove material where it wasn’t really needed, but the final bot will still end up around 225lb.

About a week later, this showed up! I sent these out to a local shop which the company has built up some rapport with, and they laser cut it from 1/4″ regular-ass P&O steel. Nothing too high tech going on here, though I recommended they stock up on ARx00 steel for future robot seasons…

Because I wasn’t in control of the machine any more, I very liberally oversized all the slots and shrunk the tabs – I went 0.015″ oversize in X and Y for planar square slots, principally. This turned out to be a near perfect, slightly jiggly fit. Laser cutting generally has a less clean finish than waterjetting, plus I couldn’t order them to “move the laser inwards 5 thou” like I typically fudge nozzle offset distances when waterjetting personally.

 

The machined parts needed for this new Pokey Dingle was really just the output dead shaft/epic standoff. I used some 1″ precision ground shaft leftovers and end-tapped both sides.

It was then used as a welding fixture. The P&O (pickled and oiled hot roll) steel was very clean from the get-go, not needing the intense sanding/brushing typical of A36/A514 hot roll or tubing products.  So it was literally just 10 minutes of MIG blasting here.

I modified the Harbor Freight Robot Tallywacker this time by cutting off the heavy punch weight at the back – it’s just a 2″ steel billet chunk. Previously I drilled a 1.25″ hole into it and welded it to the output shaft. This time, the 1.5″ main body section is more interesting, since it will be cross-drilled and bolted to the tube socket.

 

I then proceeded to get carried away.

It started out innocently enough wanting to paint the frame of the New Pokey Dingle my signature Overhaul Miku Blue – and then I discovered I had a Miku Magenta can I never used!

Yeah, well, this is what you’re getting now. aestheticbot9001

I was also tempted to paint the frame itself a light pastelly purple, but by this point didn’t want to disassemble the thing again.

Marking and drilling the front mounting holes for the NPD which brace the thing against the massive C channel section of the front of the bot. Another reason I didn’t like the old NPD – it only was bolted to the bottom of the the bot, meaning a hard enough hit and it will probably just bend. The New Pokey Dingle acts as a truss structure to past the center of the bottom plate – hopefully this will yield substantially more rigidity.

Drilling the holes themselves was an adventure. It was too heavy to put on a drill press, and too tall for the Bridgeport. So hand marking and drilling we go!

I’m rather fond of step drills. For hand drilling in steel, twist drills are almost inevitably too aggressive and tend to either spin in the drill or catch and throw you halfway across the room. Step drills feed more controllably and never dig and then slam the drill into your kidneys.

I machined a small donut piece to bridge the gap between the shaft bushing and the plate sprocket’s 2″ bore.

The same annular cutter I used for the original Pokey Dingle (as well as Overhaul’s gear holes and a lot of other parts) was used to put in the 1.25″ bushing hole. Really that was the only operation needed here! Just a single, albeit massive, cross hole.

Then you clean the parts and MIG-smash them together!

Here’s how it is going together. Since I don’t really care about the precise alignment of the socket tube, all the bushing has to do is center it. I put a few tack welds around that end first and more solidly welded the other side (carrying most of the load) – welding too much around these bushings would deform them due to the lower melting point of pressed-together bronze particles (not to mention sweat oil everywhere!)

Installation was simple, with just a few shim washers needed to space everything out.

Well, I ended up taking the whole bot apart again anyway, so maybe I should have painted the frame purple. But here’s how the New Pokey Dingle elevator machinery bolts in – a line of nuts on the bottom, and the four big bolts on the front.

I broke into the electronics enclosure again to add the 3rd Brushless Rage. I ran out of production-spec boards at this point, though, having packed the majority of them already for product shipment and BattleBots, so I pulled out one of the previous version power boards (The signal board is the same production-spec one though, just an older power end revision).

The 1″ UHMW top lid had to be modified a little to clear the new sprocket placement, which was a simple jigsaw job with drilled holes at the vertices to turn the saw around.

And here it is put together! The final weight? 226.5 pounds (with the top plate, which isn’t on here). I could probably knock 6 pounds out of it somewhere, but that’s not really the point.

So that’s where Sadbot sits now! It drives great withe dual 80mm “melon” drive, but I haven’t fought it against Overhaul yet or otherwise substantially battle-loaded it. In between the first photo and now, we actually moved shops again, and Sadbot is still hiding behind a few pallets. So, watch for both a post about the #NewVapeShop(tm) as well as some more testing and driving videos.