It’s awesome that you are working with the Arduino – thats how I started and I think it was probably the best approach to learning about electronics. I’ve been studying for my undergraduate degree in college so I have very limited amount of time to browse the Internet which is why its been hard to get around to your question.

This project you referred to was lost in a computer crash – so I have no code to give you. But let me give you a few hints.

I used the “Minim” library for java that you can find here: http://code.compartmental.net/tools/minim/. I believe this library is now included with Processing now (the platform I used to communicate over serial to the arduino).

Minim requires an audio input, so you can either run a splitter from an ipod to your microphone port on your computer, or use some sort of software to route the sound output from your computer back as an input. I ran my software on a Mac so I used a piece of software called SoundFlowerBed.

Anyways, Minim has a BeatDetect class (seen here: http://code.compartmental.net/tools/minim/manual-beatdetect/) It was useful in the video I had but it can be pretty jumpy sometimes.

You can also use what is called a Fast Fourier Transform (FFT For short) (Minim does this too, check out their documentation.) An FFT basically takes your audio input and seperates it into frequency ranges. So basically you can tell how loud the audio is from say 0-60 Hz and compare that with the entire audio signal. From there I was able to basically look at the “jumps” produced by the bass of the music and determine if that is a beat compared to how the jumps occurred in the last say 10 seconds.

Beat detection is a fairly complex thing to do – and I never got it to really “work” half of the time. For example, a snare hit spreads across the whole frequency spectrum of hearing (20-20000Hz) so when I compared the lower frequencies to everything else, it just seems that it fit in.

I went a long way since then, and found the best effect is when you just change the intensity of the light with respect to how loud those lower frequencies are. You can see this in my video I attached of my last lighting project.

I hope this gives you some ideas, good luck with your project.

Can you tell me more about what you mean by ” I was using C# and kept writing directly to the stream when I noticed a significant lag in sending and receiving data. I thought it was the Xbee until I wrote to the stream’s buffer instead of directly to the stream output.”

I too am communicating with one side of my Xbee’s using C# code. What is the difference and how do you write to the buffer instead of the output?

Thanks!

Justin

I have a fascination with LED lighting and I made a wireless “wall washer” using Xbee to individually control 8 high power LEDs. I’ll be putting up documentation on the project sometime soon with the details on that.

I am definitely continuing work with the Xbee modules, especially in home automation. I am working on possibly starting up a company to do Xbee related kits. Stay tuned.

Andrew

I have been ‘playing’ with these on and off over last year and a bit and they are really easy to get up and running.

Your tips above are a good pointer to those just starting out.
Cheers,
Dale

I’m curious, what are you using the Xbee for?