Originally Posted by Andrew Schreiber (Post 1308223)

One of the guys at my local space has a series of nasty scars up his right side from when his quad turned on and the blade caught him. Turns out CF blade vs skin… the CF wins by a lot.

Don't forget these are machines with a simply crazy amount of power.

When working with your batteries be careful not to short them. Be careful flying near people, even a small quad dropping at someone can hurt.

Originally Posted by yash101 (Post 1308369)

Also, using a linear voltage regulator at those currents would cause the magic smoke of death to puff out of the regulator. Powering my RasPi from an LDO gets the chip so hot, I have it connected to the aluminum chassey of the robot for a ginormous heat sink!

Originally Posted by yash101 (Post 1308415)

Yeah. Thee Arduino should draw about .2-.5A. The Gyro and other sensors may use up more, so you may use close to 1A/Hr!

Originally Posted by efoote868 (Post 1308191)

If I were to approach this problem, I might start by looking at what's available to the average consumer / near hobbyist level. I believe brushed DC motors are used on the popular Syma S107G model and knockoffs, and searching Ebay I can get a pair of them from China for $6 (including shipping).

One could also try to cannibalize more of that helicopter to get appropriate (and proven) gear ratios, as well as mounting hardware.

Controlling a brushless DC motor is not trivial, which is to say that as a hobbyist you wouldn't build one from scratch as you might an H-bridge or other brushed DC motor controller.

Originally Posted by efoote868 (Post 1307874)

Well, if you're still in the planning stage, you need to first figure out what you want as the end product, and then you can begin to fill in the details of how to get the end product.

Originally Posted by tilky (Post 1307853)

thanks for the pointer about the diode. finally, any suggestions about specific mosfets to buy (don't forget, will be operating at 5v)? and do i need to use resistors at any point, whether from the PWM signal etc.

oh, and is a "snubber diode" a specific type of diode or will any type do?

Originally Posted by nuttle (Post 1308239)

Bottom line is there's a ton of stuff already done for this particular application and you probably want to at least start with what is readily available and in widespread use. The underlying technology is similar, but you most likely do not want to try to build your own controller -- lots of optimization has already been done, just as for motors for this application.

Originally Posted by efoote868 (Post 1308191)

If I were to approach this problem, I might start by looking at what's available to the average consumer / near hobbyist level.

Controlling a brushless DC motor is not trivial, which is to say that as a hobbyist you wouldn't build one from scratch as you might an H-bridge or other brushed DC motor controller.

Originally Posted by Andrew Schreiber (Post 1307834)

I'm using http://www.hobbyking.com/hobbyking/s...ontroller.html for mine.

Originally Posted by philso (Post 1309718)

FRC is an "Engineering Competition". I know your quadcopter is not for FRC but the same though process apply.




The answers to these questions are not rocket science but to properly address them (and the interactions between these choices) would require more than a few posts on a forum like this. If you were in the Houston area, I could help you out. Otherwise, there may be a hacker/maker space near you with someone who has hands-on experience doing this. If you are feeling adventurous, you might consider reading application notes from MOSFET manufacturers such as Fairchild, Infineon, Vishay and others. If you really want to get into it, there are books such as the one by Mohan that are classics in the power electronics field (http://www.barnesandnoble.com/w/powe...an/1101194755). Unfortunately, quite a bit of the advice you have been given in this thread will likely cause the release of a lot of "magic smoke" and lead you to waste time and money.







Even though I design large motor controllers for industrial applications in my day job, I would still buy a ready made one for a project like yours since it would be very difficult for me to beat the price. You have more than enough challenges to overcome in other areas of your project.




I think these are the ones that several of my co-workers use for their electric airplanes and helicopter.

Originally Posted by yash101 (Post 1309767)

I will more-or-less have to agree with you in many ways and disagree in a few ways. The fact that you mentioned, that you need to go by the same engineering process as in FRC is nothing but correct! Ryan, you may want to skim through this. However, where you said that a lot of stuff we told Ryan wouldn't cause magic smoke to appear, if done right. And yes, this ISN'T rocket science (though that is just an exaggeration because rocket science isn't as hard as developing a nuclear reactor) :D. Also, what is this company you work in? I am designing a microcar, and I am having a difficult time in finding a good speed controller that is a lot more advanced than those crappy DIY ones available! Everything will be controlled by MCUs, like the QC we are talking about!

Ryan, after you build this with Arduino, I'd like to see you post a video of it, and for a challenge, you should place an RPI doing vision tracking to automate this QC! :D

Goog luck!