Simple Small Robot

Project Logs

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"Final" CAD
Andrew Schreiber • 08/10/2015 at 01:26 • 0 comments

So, I spent some time today putting the final elements in CAD, I'll spoil you with a series of pictures from that before going on to boring details...
Above: The top armor removed to reveal the inner workings.
Above: A shot of just the inner components.
Above: Front shot showing how low profile the bot actually is. Yes, I know if it were actually for any sort of fighting I'd want the CF armor panels to go to the floor.
Above: And a top view.
It probably will need some extra mounting holes along the sides (and it def would if it were to see combat) but this is just a demo robot, the most dangerous thing it'll probably face down is an overly ripe gourd.
The more I think about it, a spinning blade bot, while showy, is a TERRIBLE demo bot because of how horrendously dangerous it is. There might be a later revision switching out the spinning motor mount for some sort of lifter or grappler. Actually, a grappler could be really cool to do and fairly simple given there are low cost servos that can lift a pound or two with a 4" lever arm.
So, minor setback, I found the only way to buy the eflite connectors on my batteries was either as part of the receiver board ($60) or as part of the charger adapter ($12). Good thing I only need 1 for the wiring harness. Speaking of which, FINALLY managed to get the GF interested in this little project and she agreed to help me solder together the wiring harness. Which is good because I'm actually really bad at soldering. But either way, I have the charger adapter so I can wire up a test set using some .1" header cables. At least get things driving and connected. The second charger adapter is on order from Horizon Hobbies thanks to my local hobby shop.
Design Coming Together
Andrew Schreiber • 08/09/2015 at 00:32 • 0 comments

Spent some time today designing the rest of the bot and how it's all going to fit together. Only minimal changes. I lengthened the chassis by 10mm to add some room for the battery leads. I also added a bracket to hold the ESCs and the receiver. I still need to chop some slots for the wires to route inside the chassis.
The light blue is the battery, 450mAh. The other blue piece is the 3d printed bracket for the ESCs. it'll be held in place by the carbon fiber armor. That armor will be held on using some heat set brass inserts so it'll be easy to open up and I don't need to rely on taping into printed plastic.
Still to do are a few small brackets to hold the motors.
Framing The Problem
Andrew Schreiber • 08/07/2015 at 21:30 • 0 comments

So, I decided to try out OnShape as a CAD software. Previously I'd worked primarily in CREO 2.0 and struggled with it (I know Solidworks and Inventor far better). I'm also a Mac user and using a VM to do CAD was annoying. So I heard about OnShape and decided to see if I could whip out a frame in it. Guess I can.
You can also copy the file and make modifications inside OnShape at (I assume) Mini Robot Frame
Making ESCs Smaller
Andrew Schreiber • 08/02/2015 at 22:02 • 0 comments

So, the Vex 29 Controllers are great, cheap capable little controllers, but for this project they are actually too big. The good news is, most of the size is actually just casing. So, the first one I broke down I used a utility knife and a flat head screwdriver. It was scary. So the next three I tried something different, I put the screwdriver in the seam between the halves, a couple LIGHT whacks with a hammer and a twist of the screwdriver, and it cracks right open.
So here's the controllers and motors for the drive system. Next step is shelling out the receiver, but that has tabs and will be easy to do.
The batteries should shipping from Arkansas (Hobby King US East) and I expect them by next weekend (which is conveniently when I can work on this) Sadly, I just didn't feel up to stripping down my printer's extruder today so no update on the frame.
Gathering Components
Andrew Schreiber • 08/01/2015 at 20:26 • 0 comments

As of today I've gathered the majority of the parts. How absolutely tiny this thing is really started to sink in.
No, seriously, that's the motor and a normal quarter. I've also started pulling the casing off the Vex 29 Controllers. It's the only way things are going to fit inside the bot. Fairly simple to do, simply put a blade in the seam of the casing and twist. It'll pop right open.
I also went to the local hobby shop to sort out the issues I was having sourcing a receiver and transmitter. The guys there looked at me like I was crazy for trying something that small. So they hooked me up with the smallest 4 channel receiver they had and helped me figure out how to make it talk to a transmitter.
Earlier this week, I tried to print out a prototype of the frame but my printer extruder jammed halfway through, haven't tried again since.
So far, not counting transmitter, I'm about $110 in on this project not counting the $40 for the speed controllers (I've got a ton of those sitting around)