Building a Fighting Robot (part 3)

Shipping Delays

Andrew Schreiber
Jul 28, 2017 · 4 min read

No updates the last couple days, why? Simply put no progress. Work kinda got in the way but, really more importantly, shipping got in the way. I’m still waiting on the wheels from Banebots. USPS said today but, well, they aren’t. Hopefully tomorrow. I’m also missing the weapon motors.

Neither snow nor rain nor heat nor gloom of night stays these couriers from the swift completion of their appointed rounds

Except apparently nice weather does. Nah, that’s mean, our mailman is great, nice guy. It’s at the regional facility according to them. Whatever, no big deal.

I have received the batteries, went to get them charged only to realize I didn’t have the right connector for my charger, heading into the space tomorrow to build the cable (I don’t like soldering at my place cuz of the cats). I’ll also likely take a first pass at the wiring harness. Current electronics:

  • 1x 450mAh battery
  • 1x Fingertech switch
  • 2x Vex Controller 29
  • 1x 6ch Receiver
  • 1x Afro 12A Brushless Speed Controller w/ BEC

I’m currently debating if I want to put connectors on all my motors, I have micro JST connects that should handle the drive motor current, they won’t take up much space. I’ll see, I’m pretty sure they are locking if they aren’t it’s definitely just getting soldered in. On one hand, lose match cuz connector comes undone, on the other, lose match because I couldn’t swap a motor in time. Decisions decisions… which is funny given the whole thing should explode gloriously and provide entertainment for me and anyone who watches the video on youtube.

Oh well, enough rambling. Tomorrow I’ll do the wiring harness and hopefully test driving out on Rev 2 of chassis, I have a Rev 2.1 designed but I think I’m going to skip it and move on to Rev 3 without printing 2.1 The big reason being that I think I came up with a good way to reduce plastic weight and achieve all the goals of Rev 2.

Rev 2 Side View

Here you can see why Rev 2 added more plastic. I’ve expanded the entire bottom to act as a skid plate to keep the drum off the ground. However, this adds a HUGE amount of plastic to the frame as well as complicates if I ever wanted to machine this out of plastic/aluminum/Jello. After discussions with a friend i’m going to add a bent sheet metal bracket underneath via screws to act as both the skid plate AND feeder wedgelets. This will help get under opponents so the drum can smack them better. Bonus, I now have an excuse to order thin sheet steel so if I have weight I can skin the sides with it to deflect blows rather than giving them something to grip.

Rev 2 top view

This change added some plastic but, after destructive testing of a spare Rev 1 frame (someone threw it at a concrete floor, plastic bounced off my safety glasses… kids I’m a professional, I swear) I realized the front forks felt a little weak. So I expanded the round shape to be more of an egg and rounded off the remainder of the corners. It looks substantially more resilient. Idk, I’m a software engineer, I make pretty pictures and yell obscenities at javascript during the day. Don’t listen to me, you want someone to listen to? Rob Cowan is pretty clever, in fact, I based good chunks of this design on his Sgt Cuddles build go watch it.

He also has a series talking about the construction of that thing. It’s pretty cool. While I’m giving out resources I used — Charles may have questionable choices in vehicles (and headphones) but he builds cool robots, or, you know, he build stupid things that break your brain (Stance Stance Revolution) And, I mean, the Riobotz Combat Robot Tutorial [warning PDF] is really the gold standard, no really, the printed copy is almost a gold color, but they also distribute it for free.

I’ll leave you with a shot of Rev 1 with it’s teeth smashed in.

Rev 1 with face smashed in. Please ignore my obnoxiously yellow tables.
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