Monday, August 29, 2011

Shenanigans, Light Sabers, etc.

Well with the first week of school happening and me now possessing an R/C vehicle that drives on freaking walls and ceilings, I've been quite distracted. I've been working on designing a little motor-driven pan and tilt mount that holds one of these unsafely powerful lasers light sabers that Alex will be spending way too much money on though. If you don't know already, these lasers cost thousands of dollars because...well, let's just say light saber is literally a better name for them, rather than laser. I'm pretty excited to carve my name into unsuspecting people's arms from afar see it in action. So here's v0.2 of the pan and tilt mount:

Don't ask about v0.1, it was just a bad idea altogether.

So I designed this thing with my new love in mind. It's like 90% laser-cut acrylic, because when your suction car which has an acrylic chassis falls from a 10ft ceiling three times and everything but the chassis breaks (I don't want to talk about it), acrylic suddenly becomes the new steel. I think it will look awesome with clear acrylic anyways...oh speaking of which, I can actually apply that material to parts in 123D.

Instant cloak of invisibility.

The gears will be laser cut from the wonder-plastic that I've been dying to work with, Delrin. You don't even know how excited I am to design my own gears, by the way. Oh and then the little aluminum main mount will be machined by Alex because he loves me (although I guess this whole design isn't really for me anyways), and because these people lied and apparently I can't use the UCF machine shop after all. Oh well.

Then of course the actual pan and tilt functions will be powered by these little gems that I love so very much. This of course gives me an excuse to design some extremely simple motor controllers and maybe learn a little more about those silly little electrons. I ordered some of these incredibly awesome little joysticks partly to control this pan and tilt thing, and partly just because...LOOK AT THEM! You want some too, don't even try to lie. Anyways...looks like I'll be designing my first H-bridges. I've hardly even thought about that yet...I'll get around to it.

Saturday, August 20, 2011

Drum Roll Please

So over the past couple days I've been conducting some research on this new little project of mine that totally sucks, trying to optimize its performance and such. I settled on 40% throttle for the fan as the lowest I'd ever go. That setting works perfectly for walls and ceilings and there is minimal traction loss. At that setting, the car's ability to stick to surfaces is however all based on suction, meaning that if I run over an obstacle too big and the chassis gets raised off of the surface too much, there is not enough thrust to keep the car on that surface until suction can take over again. At 40% throttle, battery life for the fan also seems to be around five to six minutes, which I say is pretty decent. Battery life for the drive motors, which all run off of the tiniest, cutest little 3S lipo ever, is probably like 15 minutes...or something. I haven't even tested it but after a five minute run the 3S pack's voltage only drops about 0.4 volts.

Anyways, now that I'm back at UCF and reunited with this guy, we took some video. And without further ado, here it is, the feature presentation.

Tuesday, August 16, 2011

It Lives!

Well this is exciting.

The Ponoko laser cut chassis has arrived! The final piece to this seemingly never-ending puzzle. It's really nice too. Once again, I definitely recommend laser cutting. Time to put stuff together!

This is so exciting. As a result of the excitement overload, from this point on I kinda didn't take any intermediate pictures. So here's the finished product with everything stuffed onto the chassis.

If you look carefully, you can see the gobs of epoxy holding the ducted fan in place. I just really did not want a brushless fan with 540 grams of thrust coming loose. And now for another view.

I call this one "OH MY GOD WIRES".

Oh umm...anyways, keeping things short and sweet, it works.

Ignore the shirt.

It's extremely loud, like you don't even know. It sounds like a jet engine. It also works on ceilings (although I don't have a picture at this very moment), and the ducted fan is only running at 50% throttle for both wall and ceiling use. It absolutely killed the batteries the first run, lasting for about two minutes total, but I don't even know if they were fully charged. It was just a quick test run to see if it worked. I'm pretty sure I can reduce the throttle to 40% or even 30%, and I'm really hoping to squeeze five minutes of run time out of it.

SO, coming soon to a blog near you (...this one), I'll have test results for battery life when I have the amount of throttle absolutely necessary from the fan tuned in, a video, and ramblings about my ideas for v2.0. I might even actually organize the wiring on this thing. I'll post again within the next few days for sure.

Sunday, August 7, 2011

Oh The Anticipation

I don't really like the idea of posting mini hey-look-I-got-some-parts-but-can't-use-them-yet updates but that seems to be all I've got for now. I can explain. First though, look at these new parts that I got but can't use yet!

Here are the awesome little Pololu wheels and micro metal gearmotors:

Yeah they're pretty sweet. Next up, the incredibly powerful ducted fan, accompanied by its partner in crime, the Hobby King 30A speed control:

This thing is seriously insane, especially since I'm using it with 4S power so there's nothing holding this fan back.

Oh, also, those little GWS speed controls that I got suck. I soldered them to some very small test motors just to make sure they work know how electronics can be. The first one's BEC transistor exploded upon plugging it in for no reason. Didn't even get to use it at all. The next one worked the first time I used it, but then the next time I tried, it just didn't work. The BEC circuit was working fine because the receiver was on, but the test motor just wouldn't spin. I emailed GWS customer service and after a few emails back and forth of the guy doubting that I was using the size battery I said I was, he stopped emailing me back. Fuck GWS. That being said, here's a picture of new speed controls I bought. Their features include:
1. Lower price tag than GWS.
2. Double the amperage capabilities of GWS.
3. Pretty blinking lights which GWS did not have.
4. Operational. (this one's a real luxury)

Blue Arrow. Never heard of them. But as you can see their features list is impressive compared to the GWS speed controls I bought before. Now, here's a picture of the speed controls soldered to little test motors and plugged into the $6 receiver I got from the great Hobby King which by the way works perfectly.

Well anyways, at the beginning of this post I promised to explain why I'm posting yet another mini hey-look-I-got-some-parts-but-can't-use-them-yet update, so here goes that.

Ponoko takes forever.

More explaining. You see, I ordered a nice piece of carbon fiber for the chassis of this vehicle that I was going to have a friend cut out on his CNC machine, but I decided to get adventurous and use Ponoko's laser cutting services for the first time instead. I uploaded my design and ordered it and all that good stuff, and shortly after learned that it takes about three weeks to receive a part.

Three weeks. That's like three years in engineer-time.

So I'm just waiting anxiously. It should be about another week and a half before I have it and then I can finally put all this stuff together and make it work. By the way, it only cost $5 for the materials and cutting service to make the chassis out of acrylic, which is incredible. Besides the fact that they kinda shafted me with a $12 shipping charge, I would definitely recommend Ponoko to anyone looking to make small to medium sized 2D parts. They do 3D printing too but I don't know much about their 3DP services. But yeah, for now, this is all I have as far as a chassis goes:

Paper certainly isn't a very sturdy material, especially for a chassis, but it's good for mock-ups!

I would install the ducted fan and wheels and stuff know, paper. Not good for much more than lying flat.

Well for now that's all I've got. As soon as my chassis arrives I'll be able to actually put everything together and perform testing and take videos and all of that exciting aftermath of projects such as this one.