Sunday, December 21, 2014

Attempt at The Aesthetically Pleasing Quadrotor

I've always loved flying things despite my evident affinity for ground vehicles (they're easier to put a person on). This summer I was given a few small motors so I bit the bullet and bought a complete set of parts. My hesitation up to this point was that homebuilt quads out there are, for the most part, kinda ugly. Yes, hobbyking sells some cool frames, but my real issue is the exposed wires and other electronics...and the overall 'janky' look. Things like landing gear and some of the more intricate wiring organization haven't been totally fleshed out but here's my attempt at a 'pretty' 3D printed quadrotor.

Inside, you can see the motor controllers (red), the flight controller (green), the battery (blue), and the receiver (gray). I don't think I forgot any parts but I'm honestly not sure.

Top is held on by a few screws

The base

Section view. Wiring between motors/controllers will run through the hollow tube arms and up through the holes at the bottom center. 

Printed a draft of the bottom on Rufus. After this I made a few modifications to avoid unnecessary support material.
Updates soon to come!

The guitarist's best friend: Kaye-Po

A friend of mine named Kaye plays guitar. She lost her capo. I made her a Kaye-po. Ha, punny. Don't tell her yet - it's a surprise.

The whole concept is pretty straightforward. It took only two tries to get the locking mechanism to work. The purple stuff is PLA and the orange stuff is O-Ring cord stock to protect the guitar neck and mash down on the strings a bit more gently/consistently. The model in the pictures was intended as a prototype but at 50% fill it is plenty strong. The pieces are held together by 8-32 screws and the holes for the rubber bits are tight enough to hold them in place. The final versions will be 100% fill for safety, will ideally have black rubber bits, and the pieces will be printed in a consistent orientation.

The teeth on the ends lock into each other and can be adjusted for different neck sizes and tightnesses. A friend named Chris also found that this capo has a convenient quick release feature.

Screwdrivers are like guitars.

Text on the side

Thanks to Dan and his guitar for being wonderful models

MacroKart - Transient Version 2

Wow, this hasn't been updated in a while. Since the last post on MacroKart, just about everything that was made of wood is now metal, and the thing went through a brief period of complete functionality before I decided things needed to change... but we'll get to that. This summer I had a friend machine a few parts for me since I was at work during shop hours. These parts included the front wheel uprights, the motor mounts, and the brake mounts. I also borrowed a stem from a friend's bike for the handlebars.

3D printed steering column support

The tube was too small so I had to improvise.
 I also changed the throttle to a twist throttle. The pedal required my foot to be uncomfortably extended at full throttle.
Brakes partially complete

Brake assembly after a bit of use

Here's a short video of the brake supports moving. I don't have a video of one with the complete system, unfortunately.

At this point, the kart was complete. I rode it up and down the street many many times. I did a few time trials and found that I was going about 17 miles/hour. It was fun, but I wanted MORE. So I bypassed the current shunt on the controllers. this involved removing the loop of wire in the picture below and replacing it with a shorter copper wire. The picture below also shows the capacitor that fell out of one of the controllers when I opened it. I guess it wasn't important. I soldered it back in anyway.

This was a huge success. Big boost in acceleration and about a 30mph top speed. As a result, I was blowing 60A fuses like it was my job. At 33V, that's two '350W' controllers burning through 1kW each. Below are two of three that I blew the first week. After that, I was more careful and did fewer 'full-throttle-from-a-stop' runs. I had 5" wheels - the acceleration was something fierce, I'm tellin ya.

Sadly, all good things must end. Not that my controllers were particularly good, but they both died after about three weeks with the current boost.

On to bigger and better things. I pulled out some 8" pneumatics and put them on the front wheels, yielding a pretty goofy looking setup.

Just for fun, I threw a controller on the left motor and did a few runs up and down the street. I ran into my friend Amir, who took a lovely picture and then went on his way.

Summer also participated in the Imagineering 500 and took both first and last place.

Current status: I have two Kelly KBS36101 controllers and sensors mounted on both motor cans. Rear wheels have been replaced with razor scooter wheels that come with brakes! I need to mount the controllers, wire precharge circuitry for the controllers, attach throttle, sensors, power and finish the brake supports/cabling. I'll also probably redo the steering column and have something a little more robust holding the handlebars in place.