Weekend In Review
I guess I didn’t put a post up for my weekend plans. Probably because nothing super exciting was scheduled. The only thing I knew of for sure was a family dinner at our place on Sunday. That was a lot of fun. Amber and Brian didn’t come because Amber had to work (Brian, you should have come anyways, you would have had fun regardless).
I suppose I haven’t mentioned my new hobby yet either. I’ve taken up building little electronic devices. I bought one of those “500-in-1 lab projects” things that is teaching me what all the little pieces do, and how to put them together so that each of them gets the correct voltage. My first goal in this is to create a helicopter with 4 propellers. What interests me the most about this idea is having a chip on-board that can tell if the craft is tilting in any direction, and then automatically adjust the engine power to compensate.
Saturday I received the accelerometer (tells if it is tilting) and the ultrasonic range finder in the mail. I haven’t had time to hook up the accelerometer yet, but I did get to play with the range finder. It’s pretty stinkin’ neat. I also wrote the little snippet of code to calculate the speed using the range finder. In the end, I want the helicopter to be able to land itself as quickly as possible (for when the battery gets low on power)…so I’ll need to be able to cut the engines to a minimum, and at some point turn them back on to keep it from crashing into the ground. I think I have that part of the problem solved.
I also bought an infrared receiver from the Radio Shacks and hooked it up. After a little bit of playing, I can now decode the signal coming from the TV/Cable/DVD player remote controls. Since I don’t want to buy a real remote controller, I’m going to use a TV remote to control the helicopter. At first it is just going to be a simple thing that you type in “10″ and it will start flying 10 ft off the ground. Something along those line. Maybe you hit a direction button and then a number and it will travel that far in that direction. Maybe the volume buttons increase/decrease the height it is flying. If I can get it to work reliably (without flipping itself over) with simple commands like that, it should be trivial to hook it up to a controller that will allow advanced maneuvers.
I think either today or tomorrow I will get the motor drivers in the mail. They are just a chip take a digital input and converts it to the full amount of power going to the electric motor (allows you to supply a little bit of power, or a whole lot of power, or somewhere in between). After I get that figured out, the only real challenge left is building the frame for the aircraft.
If I can make it light enough, then the motors I buy from Radio Shack will work fine. If it is too heavy, I’m going to have to buy those expensive motors from a hobby store. If that’s the case, I might make it into a single prop helicopter…which kind of ruins my plans. I could still use all the stuff though, and just make the prop work with a servo to tilt it in a certain direction.
After I build the helicopter, I think I’m going to build a robot.
June 30th, 2008 at 11:42 pm
Casey,
Sorry I didn’t make it to your dinner this weekend. On top of my online classes I have been taking an 8-5 class and it is really kicking my ass. I couldn’t do my homework Saturday because of the gig I got, so I had to do it yesterday (Sunday).
That helicopter project of yours sounds pretty damn cool too. You’ll have to show it to me some time. And just to clarify, your helicopter needs at least 2 propellers/motors (i believe the correct technical term is a rotor). The reason is because of the gyroscopic force generated by such a large “wheel” spinning in one direction. On a conventional helicopter (one with a vertical tail rotor), the tail rotor is used to cancel out the gyroscopic rotation induced by the main, horizontal rotor.
On a coaxial (i think that is the right term), the helicopter has 2 identical horizontal rotors (no tail rotor), and each rotor spins in the opposite direction of the other, thus canceling out the gyroscopic rotation. The military uses coaxial helicopters (a chinook is a similar idea) when they need a more stable and steady flight platform. Just FYI
So, I’m not sure how a 4 prop (rotor) helicopter would work, but you are definitely going to need at least two. Also, if you want some ideas on how to implement the pitching/yawing process that controls the direction of the helicopter, you might want to go to Frys and buy one of those little 40 dollar toy helicopters. They are real basic, but still the same principal.
Also, I don’t know what your specific plans for the helicopter are, but I would imagine you would want to stay fairly simple, which means that for controlling height you will have to use faster or slower motor speeds.
Anyways, hope I didn’t rain on your fun, but I thought I’d just share some of my helicopter wisdom.
Also! If you and Kim want, I am playing a fourth of july gig in terrell on Friday…a concert at 8. If you guys are interested, maybe you two and amber could meet up and go out there for the concert (i will have to be out there early to warm up). I don’t know about beer, but I know there will be fire works. If you are interested let me know and I’ll try to get more details. I could be wrong, but I think it is free too.