# Recent content by KLoux

1. ### I Help Understanding Luminance Calculation Process

Hello all, I have a system that consists of: A projector with a known position, orientation, and brightness (luminous flux, I guess - units are lumens), A lens with known distortion characteristics (i.e. a known light ray vector for every point on the projector's image-generating panel) A...
2. ### Friction Measurement of Rotating Equipment

Hello, I have two questions that I have been pondering for some time without arriving at an acceptable explanation. The questions require a little bit of background information: I work on rotating machinery that operate across a range of (relatively slow) speeds, and generally has a...
3. ### Extended Kalman Filter(EKF) concept (SIMULINK)

I haven't looked at your attachment yet, but here are comments on your two questions: 1. If you're initializing the state vector, you should initialize the covariance along with (i.e. what is your confidence in your initial state estimate?). 2. Can you be more descriptive? Are you using some...
4. ### Harvesting Load Cell from Food Scale

Hello, I've been toying with the idea of making a cheap dynomometer for small electric motors, but one of the obstacles I'm encountering is finding a cheap load cell. The best I've done so far is a \$75 sensor from Omega, which still requires conditioning. Then it occurred to me that you can...
5. ### Can this be solved?

Hello, I have an equation which I am trying to solve for t. Of course the problem I'm having is due to the combination of ts within the argument of the sin term and also outside of it. I think I could also manage without the constant D (using sin(x)/x=sinc(x)), but that's no help here (as...
6. ### Brushless AC Motor Windings

Hello, I've recently read a couple of things about brushless motors that have spurred quite a few questions. Googling has solved some of them, but I'm hoping that you can help with the rest :smile: Apparently there are two types of permanent magnet brushless motors - DC and AC. This is...
7. ### Sound intensity using decibel values

You'll need to post more details. What answers are you getting? What did you try? Show step-by-step. Also, check that you copied the book answer correctly for (a). -Kerry
8. ### Mechanical power transmission

I think it comes down to how your defining efficiency - if you consider efficiency to be power out / power in (this is usually what is meant by efficiency), then Bob is right and efficiency is not a function of position. If you are looking at it from some other point of view (torque, velocity...
9. ### MATLAB Calculating FT using matlab quad function

The error that your receiving about functions being undefined for inputs of type sym means that you're trying to send a symbol into a function that is expecting a number (or numbers). Here, my guess is that you need to use finite limits (inf and -inf won't cut it). Try replacing them with...
10. ### 2D Collisions

What do you mean, it doesn't account for friction? Where is it that you are expecting friction to come into play? Can you give an example? Typically, this type of problem involves considering the system just before and just after impact, so if there is friction between the two bodies and...
11. ### MATLAB Matlab load question

Have you tried using single quotes around the file name? The documentation has some information about backwards compatibility - sometimes you need to add a flag like -version4 to save it so older version can open it, but my guess is that this is not required for 2008 -> 2007. -Kerry
12. ### MATLAB 10Hz High Pass filter with Matlab

I'm not familiar with the MATLAB command fir1(), but here are some thoughts: 100 is a pretty high order for a filter. I would recommend starting with N = 1 and step up one order at a time until you get something you like. High orders might tend to distort your data very badly. The cutoff...
13. ### 2D Collisions

Search for "Conservation of Momentum" and "Conservation of Angular Momentum" - you should be able to find some explanations and examples. -Kerry
14. ### Dsp is:TMs320F28x

If you can convert the transfer function into a difference equation, this should be pretty easy. If you need help, can you provide us with the transfer function? -Kerry
15. ### Finding Current

What are you trying to do with the equations you provided? It looks like you're adding resistors in parallel... this is not what you want to do (what is your thought process? - maybe we can help put you back on track)... what other equations might be useful here? -Kerry