Noise Generator 2 – Hardware Updates and Software Plans
It’s been a minute since my last post on this project. This doesn’t surprise me, as I often find myself very busy with everything else going on. In this time, I’ve rethought a couple of things on this project which I believe will make it both more portable and easier to maintain.
The big change: no speaker/amplifier
“But Johnny!”, I hear you say, “How can you make a noise generator without a speaker!?”.
I have one word for you: television.
The purpose of the noise generator is, after all, to help me get to sleep. It occurred to me that every room that I sleep in has some kind of television set with, you guessed it, a speaker!
By losing the speaker, I can also make the project much more portable. No more lugging around a speaker and amplifier. The project can be as simple as a microcontroller and an HDMI cable. And who knows, maybe I can add some visuals on the screen?
Microcontroller: Raspberry Pi B3+
With the TV setup in mind, my goal is to use my old Raspberry Pi B3+ SoC as the audio generator. I’ve tested a couple of noise generation codes on Python with good success. Hopefully this will translate well onto the Pi.
Notes on the audio spectrum
My testing with the brown noise generation has led me to some interesting observations. The sample I provided in the first post demonstrated a 20dB/decade rolloff, which sounds quite nice. In preliminary testing, I notice that sharper rolloffs correspond to ‘deeper’ sounding brown noise, which can be more soothing.
Our ears don’t hear low frequencies as well; and speakers don’t tend to produce them very well. Thus the ‘deeper’ the brown noise, the louder the speaker has to be to produce the same volume in our ears. I forsee this being a problem with playing ‘deep’ brown noise. I hope to add some configuration on the software side to tune to whatever speaker setup I run into.
Going Forward
The next steps for me are:
- Write a reliable Python script for generating and playing brown noise.
- Configure the Raspberry Pi B3+ OS to boot into this script.
- Debug where I can.