Recent content by asynchronous13

It may be clear how to compute it for someone who is more familiar with these methods than I am. However, this is outside my normal field of work, so I could use some pointers. While I could do an integration over the entire blade, I thought it would be simpler to use a moment of inertia that...

I am interested in calculating the centrifugal twisting moment (CTM) of a variable-pitch propeller blade. It's been a long time since I did anything with moments of inertia, so I'm looking for pointers to good info, or direct help if someone here can provide it. Assume there is a propeller with...

The micro-controller suggestion is a good one. Another option is to use an N-bit counter and a DAC. Many counting chips will count up or down. So, connect the outputs of your Quadrature Clock Converter to the up/down inputs of a binary counter. Then the binary counter feeds the DAC...

You could use a Stirling Engine or a thermoelectric generator. http://en.wikipedia.org/wiki/Thermoelectric_generator http://en.wikipedia.org/wiki/Stirling_engine

You are definitely not alone. For me, the most painful class was Electricity and Magnetism. I signed up for, and then dropped the class twice -- mainly because I didn't like the material. I finally committed to finishing the class on the 3rd try, but unfortunately for me a new professor came...

Trek recently released a belt driven bicycle (instead of chain drive) which led to a discussion among some cycling friends. Which led to discussion of torque, power output, etc. Anyway, I'm trying to compare the chain tension of a motorcycle vs the chain tension of a bicycle. I'm better with...

The Basic Stamp is incredibly easy and quick to program. Great for quick proof-of-concept work, but also very limited capabilities. BASIC only. PICs are numerous, pretty decent, sort of stuck at hobby-level applications. C compilers available. Atmel AVRs are what I would recommend...

For hobby-style RFID check Phidgets or Parallax. Prices from $40 to $65 for the reader, the cards are $1-2 /each (for passive). Active costs more, but I don't know a brand off-hand.

Have you looked into RFID? The passive version only detects out to a few inches, but the active/powered versions can detect to several feet.

Let's say you've got a transfer function \frac{X(s)}{U(s)}=\frac{G\cdot\omega^2}{s^2+2\zeta\omega s+\omega^2} Then \zeta is your damping ratio. If I remember correctly, the damping ratio determines the shape of the step response and impulse response of the system. If \zeta > 1 then the...

There's several designs out there to run a battery charger from a bicycle hooked up to a car's alternator. Most people can generate about 100W for several hours using this method - maybe up to 300W if you are in really good shape. If you really need up to 1000W, then you'll have to pedal for...

You can also use transistors to affect current flow. You'll still have power dissipated, though.

Look, I don't know anything about your level of education, so I started simple. I missed the line when you mentioned already knowing about the data, apologies. good luck.

I think the iPod has a built-in voltage regulator, so you could probably get away with a very simple setup. However, a quick search indicates that the iPod Touch needs some data sent to it to commence charging. You'll have to send that appropriate data, not just tie the data lines to +5V.

Try measuring the batteries when they are not connected to your circuit. You'll probably find about 6V. A diagram could be helpful to help you diagnose the problem. Have you heard of Minty Boost? It's an open project that does the same thing you are trying to do. (I can't post URLs yet, but...