I’ve ordered a few more parts which are needed for phase 1.

EDF Ducted Fan Unit 2.56 inch 6 Blade

This is a fantastic EDF unit, the look, size and specifications are perfect! One problem I see is the motor that I ordered has a shaft of 2.26mm which could pose a problem. But hey, we’ll resolve that problem when we need to.

Hitec HS-55 Micro Servo Motor

Servos will tilt the EDF units, 2 have been ordered. Another component...

Since I've never made anything like this before, choosing these parts was rather hard. I have done as much homework as possible but there is no way to know how well a part is going to work with another until you try it. So here are some details..

Motors: Mystery 5000 Rpm/V Outrunner Brushless Motor D2825-5000

I was rather impressed with the weight a lot lighter than expected and the max current is perfect to allow more air time than orignally thought.

Electronic speed controllers: Mystery 30a ESC

...

After a few solid weeks of being tied up with work, I've managed to get a few hours free, and am going to try and use that time to decide on a Micro Controller.

So since we know most of the requirements it shouldn't be too hard. For the HK to work we need a minimum control over 2 servos, 2 speed controllers, 2 gyros, and about 4 proximity sensors. Other peripherals would be GPS, Bluetooth, and maybe Wi-Fi. We also require the Micro Controller it to be as light as possible. I found a few that meet the listed requirements, there is some really neat stuff out there for this kind of thing.

Qwerk
Features: 340 grams, 32+ IO, 200 MHz ARM9 RISC processor
Pros: Very powerful processor, has Wi-Fi built in.
Cons: Weight and size are an issue.

VEX
Features: 127 grams, 16 IO, PIC18F8520 Processor
Pros: Robust, very powerful processor.
Cons: Weight and size are an issue.

Axon Micro Controller (small...

External module for a 8 bit Shit Register, for use with the Oshonsoft Simulator.

Unzip the zip file to the hard drive.
Run the 74LS164a.exe file, a simple asm/hex demo file is included in the zip.

Running the *.exe will start Oshonsoft.

"I'm going to blow up the earth, it obstructs my view of Venus......"

quite often there are posts i see, that remind me of this classic cartoon line. common subjects are EMP generators, lasers (in the Megawatt or Gigawatt range), and other devices in the "infernal machines" class. usually the interest in these devices is from some type of annoyance factor ("my neighbor plays his stereo too loud", etc...)... in fact i've been known to dabble in the "infernal machine" category myself from time to time (once built a Tesla coil that blanketed the 4-story apartment building i lived in with wall-to wall RFI, and burned out every CMOS chip within 50 feet). my interest was just plain curiosity, i wanted to build one just to see it work. while i have no problem with experimenters trying stuff out to see it work, i do have a problem with annoyance driven projects whose purpose is to intimidate or exact retribution. grow up, and tell your neighbor...

Back in my early days of design, we would work out designs on paper, put them to a schematic, and head for the cad department. As time grew a certain newly appointed project engineer gave the whole design team a speech. “Simulate, simulate, simulate” he said, as he emphasized the importance of simulating ones design prior to production release.

This was very good advice and I followed it as I learned the sim tools of Mentor logic. From this project managers advice I have become a disciple of simulation in the practice of engineering.

With that said, I find far too many now rely on sim tools as a design tool rather than a check tool of ones design. Instead of working out a problem, many rely on the simulation tool to do the work for them. This is not what the sim tool is for. You must first design your circuit, have a reasonable understanding of how it should work, once the design is made, then a simulation should be run. Do not use the sim tool...

A big part in this project is choosing the size to build the HK, and also the weight. To figure this out I have been trawling the internet looking for potential motors and batteries that will be suitable. By knowing the thrust of a motor it will allow us to determine the maximum weight that can be supported and then will give us an approximation on how big to built the HK. Also knowing the battery will give us some insight into how long it will be able to sustain flight.

So in my search, I actually came across some great info. It was quite a big learning curve as I never even knew about brushless motors. I was somewhat blown away by their power and efficiency! They are smaller, quieter and more efficient that a normal bushed motor. Excellent! I found one motor which weights 76 grams and can output 1000-1500 grams of thrust. Having two of these would support anything from 2000, to 3000 grams in weight (theoretically). Batteries have also come a long way since I last checked...

it would be nice to be able to measure impedance of an AC circuit as easily as measuring DC resistance, wouldn't it? there are many times in the audio business, when i would like to find out what the impedance of something is at a particular frequency, and i usually have to resort to some indirect method. an impedance bridge is a piece of test equipment that measures impedance, but such a beast is expensive, and is an indirect method, and a bit more complicated than putting a pair of test leads across a device and reading a number. i would like to be able to put a pair of test leads across a device and know it's impedance as a direct measurement. of course there would be one added step, dialing in the frequency i want to measure at, but i can live with that one extra step. so how to go about it?

a DC DMM ohmmeter circuit is a simple device. you have a digital voltmeter across a pair of probes, and a DC current source set to a known current. if the current were for instance...

I have an idea, a big one. It's going to consume many hours - and annoy the heck out of my girlfriend, but it's going to be awesome! I plan to build an autonomous model air craft based off the Terminator movies, it's call a Hunter Killer, H.K. for short..

Since this is a rather large project I plan on breaking it down into three phases. The first phase will be building the craft (my initial thoughts are to make it approx 50cm long) which will have many hard to accomplish mechanical feats. The first one that comes to mind is solving the power to weight ratio. This will require choosing the correct materials for the hull and also deciding what types of motors, batteries, etc to use which will have enough thrust to lift it off the ground. This first phase is all about building the craft so that it has the engineering to fly.

Phase two, we have the challenge of getting the HK to hover and balancing itself (autonomously). Now, if you search YouTube for "model...

everybody should know what this means...... if not here's a linux page with a description of this command and it's usage.........
http://www.wlug.org.nz/rtfm(1)



ok, if after you read that, and you're still not sure, it means Read The Fine Manual, Read the Fun Manual, or another version not suitable for polite conversation.

working for a large service center, i see a lot of equipment that comes in for repair which, frankly, wouldn't have to if people pulled out that mysterious book that comes with your shiny new home theater system, sat down and read it cover to cover just once. and those who should read the manual are not only the consumer, but the sales staffers who guide the consumer in their purchasing decisions. two examples of this are from actual pieces of equipment that came in for repair recently one of them is from a consumer, one is from a home theater sales "tech". the first one (from a consumer adding an additional...