Parts Used:

2x Fingertech TinyESC

2x DC 6V~12V 280RPM Micro Mini Full Metal Gearbox Gear Motor

2x BaneBots Wheel, 1-3/8″ x 0.4″, 1/2″ Hex Mount, 40A, Black/Orange

2x Hub, Hex, Series 40, Set Screw, 3mm shaft, 1 Wide

Fingertech Master Power Switch

HobbyKing 939MG Servo MG

Turnigy 500mAh 3S 20C Lipo Pack

Fingertech Power Terminals

2-6S Lipo BEC UBEC 3A 5V Input 5-23V

Hobby King 2.4Ghz 6Ch Tx & Rx V2 (Mode 2)

A Dark and Dirty Disco was a bot that had MANY revisions. I knew I had Robot Battles coming up in less than a month, and I wanted to try and complete a second bot. My first bot, 10 Days Til Destruction, was made from the Viper Kit sold by Fingertech Robotics. I wanted to see if I could come up with a 3-d printed design that would work. I knew that if I wanted a bot that was 3-d printed, I would have to teach myself one of the many CAD programs available. Great idea with less than 4 weeks to competition, right?

So, first thing’s first… what kind of design do I want my bot to be? At first, I thought it would be great to come up with an ant version of the classic Middleweight Battlebot, Hazard. A dominant performer that only had one loss to its 18 matches. I thought it would be easy to come up with something in this design, so I started the journey of learning Fusion 360. This is what I came up with after a few hours of design.

I know what you’re thinking, pretty impressive, right? I can’t tell you how long it took to get those angled sides and filets to work right. Turns out I was over complicating everything in the design. I quickly realized that I should probably attempt something a LITTLE easier to design. Especially if this thing was going to be 3-d printed. At this time, I was thinking that the bot would have to be PLA, which is basically a sacrifice. I doubt any kind of motor mount would hold up after a hit with a PLA mount.

I turned my focus into creating a bot that had more of a 2016 bite force. I can’t tell you how excited I was to get that weapon mount design completed, but I quickly realized that this probably wouldn’t hold up as well. I got a little ahead of myself and ordered some pulleys and belts before realizing exactly what I needed. By the time the belts arrived, I realized my mistake of ordering severely undersized belts, which would entail basically mounting the motor about an inch away from the spinning disk. Live and learn… It wasn’t too long after this that I abandoned the idea of doing a spinning vertical disk. Did I mention that a this point I have about 2 1/2 weeks before the competition?

With an increased workload, I found myself working a lot of overtime, which really cut into my bot designing/Fusion learning time. I started to come to the realization that I probably wouldn’t get the bot designed in time for the event. I still had to add the new LEDs into my other bot (learn/teach myself how that all works) and designing a bot with 2 weeks left made it seem time was against me. I abandoned the idea of doing a Bite Force style bot, and remember a cool little Antweight lifter that I saw a few months before called “Pad Thai Doodle Ninja,” designed by Charles Guan. Four wheeled bot (back wheels have motors and front are driven by the motors in the back) with a lifting arm. I decided that instead of working in CAD, I liked being able to see the dimensions of a design, so I bought some foam board and a hot glue gun.

This is about as far as I got on that project before a friend of mine offered to help me out by offering to print the final bot in 910 nylon. I realized that I needed to get the CAD finished, and I started designing again, attempting to get a little more comfortable with Fusion.

You can start to see the design coming into play. At first, I was trying to find a CAD file of all the components I would be using in the bot (battery, motors, TinyESCs, servo, etc.). Eventually,

I decided to take-what I would call-the “easy route” and just invested in a digital caliper. This allowed me to measure all the components I would use inside the bot, make cubes with these dimensions, and insert them into a layout for the bot. This allowed me to get close enough to where the final configuration was basically the same as it looked on the screen. The picture to the right is the basic configuration. The squares that the motors are mounted into are a representation of where there would be cutouts in the base of the robot, so that the tires have a place to go through.

With about a week left, this is what A Dark andDirty Disco was looking like. I was planning on printing the motor mounts into the main body of the robot (this ends up being a pretty bad idea in the end. We’ll get to that soon enough!)

At this point, I just had a rectangle acting as a placeholder for the lifting arm. I thought I would be able to use a piece of 3/4″ aluminum with a 3-d printed hook on the top of the bot ALA Alpha Raptor (You know? Back when Chuck was dressed like a Jurassic Park safari guide?).

Side note, this was the first design that I ever designed from scratch in Fusion and printed on a 3-d printer. For a first timer, I feel like it turned out pretty good. It was also at this point that the 32 disco balls I ordered had arrived.



Based off the test fit, I realized that the Disco holder arm had to be taller. I also wanted this hook to act as a stopper, so that any bots that got on top of me wouldn’t just ride over the bot entirely. The idea being this lifting arm is not necessarily to flip the bot, but to get it lifted enough that I could push it into the 18″ opening I knew the arena in Nashville would have.

I ordered servos based off of what Charles used in Pad Thai Doodle Ninja. They have all metal gears, so I figured they would be able to mostly handle the lifting. I ordered 3 of them just in case. After a few days, they finally showed up, and WOW are they tiny!

I sketched up a servo arm attachment in Fusion, and mapped out how much overall movement I should get out of the servo with this arm attached. I was happy with this range, so this is what I wound up going with.

In the initial designs, A Dark and Dirty Disco was a four wheeled design, but after weighing everything (yes, after I designed), I realized that I was already about 20% overweight, and that didn’t include a lid or the lifting arm! With one week remaining before I left for the competition, the only logical thing to do was cut out two of the wheels and shrink everything together.

I added the spikes in the back to try and keep the front end from lifting up, but I realized that this would not only give opponents something to hit, but would also be susceptible to breaking off. Plus, at this point, I wasn’t quite sure if disco would be able to self-right, but with those spikes, it was 100% that it wouldn’t be able to. The bot was really starting to take shape. Did I mention that I’ve never designed or built a 100% original bot before? All of this is based off of a “I hope this works” attitude.



The next step was to design a lid that would cover the vitals of the bot. It wound up being easier than I thought. Sketch a rectangle that is the same size as the top of the body, and add filet, and this was the result. I was pretty happy with how the bot was coming along. I felt like I was pretty close to being ready to print!

In the end, I wound up removing the spikes on the back of the bot.

This was my big idea for how the lifter was going to work. A pin of some sort locking the lifter to the servo arm in the back, and a middle support system in the front, based off a hinge. Is that stupid? Is that going to work? I don’t know! Like I said, “Hope this works” attitude. I decided if it even remotely does “the thing,” I would consider that a victory!

I got to designing the arm, and how this whole system would work out. Eventually, this is what I came up with. It has a support pin in the bottom of the front hinge, which would be 3-d printed out of 910 nylon. This build has pretty gotten to the point of a YOLO build. The back hinge and middle hinge would be supported by a nut and bolt system that is tightened down enough that the joint can move freely.

Now that the design was basically complete, I combined the squares that were holding the motors into the design to the robot body to act as cutouts for the wheels.

I decided that before I gave the files to my friend to print in 910 nylon, I was going to print a “test fit” print out of PLA with a 5% infill and a raft. After the first few layers, so far, so good!

This 3-d printer is a Griffin XL that is at the Maker space that I’m a member at. The print

was going to take about 11 hours, so I decided that I would come back very early in the morning before work to check the print. I walked in to the printer being turned off and this sitting on the printer. A member had messaged me to let me know that the end was coming up off of the printer, and they stopped the print. I racked this fail up to thinking that I didn’t cover enough of the space with glue to hold the print in place.

I made sure to cover the full range this time and started the print again. I came in after work to find that the printer, again, was not working, and this was sitting in the printer. The print most definitely got further than the first print, and was sticking to the table, but a combination of many factors caused the print to fail again.

With two days to go before I left for the competition, I decided I was at the point where we had to start printing with the 910 nylon if we were ever going to get the print finished in time. I sent off the files and hoped the parts would fit like they should.

To my absolute surprise, most of the parts fit FAIRLY well. The lifter actually did the thing!



The print wound up being pretty light, at 13.65 ounces. You can see I wound up having to use zip ties to hold the motors in, because when I attempted to use the motor mount that

was printed with the body, it snapped off. I wound up doing the same with the other mount, drilling holes in the sides of the remaining part of the motor mount, and zip-tying the motors onto the body. So far, they have held up pretty well!

Here’s a picture showing the layout of the insides before doing some wire routing cleanup. As you can see, a lot of gorilla tape holding things down! I attempted to stack gorilla tape high enough to where the lid would press down and hold the servo in place even better, but that would have required a lot more tape than shown. The receiver, battery, and TinyESCs in the back are being held down by Velcro. The power switch was press fit into a hole in the base of the body, and taped just for extra security and access.

Things that I learned through this first design.

3-d printed motor mounts, no matter the material, can break REALLY easily (HINT: Make sure that your orientation is set up in a way to where the first time you attempt to use them, they won’t snap off)

Tolerances are important I didn’t take tolerances into consideration at all, which led to a lot of items not really fitting all that great. I had to eliminate most of the sidewall was meant to protect anything from getting inside the bot. The lid has to be taped down, because the tabs like you see in the front *kind of* fit in the slots of the body, but the screws I bought are not long enough to hold the lid down on the body.

Just go for it Before this build, I had very little knowledge of Fusion 360, so I just kind of went with it. Try not to over-complicate the build (yeah, right!). I did a lot of things in this design that are probably not ideal or “correct,” but I’m actually really happy with how the bot drives and acts. The lifter arm extends in an up and out motion, just as I was looking for.

Gorilla Tape is your friend The stand that the servo sits in has pieces of nylon that are printed that are way too thin to really do much, so I decided to use the weight I had remaining to tape all I could on the robot. I taped down the servo, the lid, the motors, whatever I could.

