Adventures with Arduino: Sound and Light Machine

Disclamer: Please note photonics stimulation can cause seasures. The information presented here is for education only, I take no responsibility for your use of this information, you use it at your own risk.

As well as the pulse oximeter project, I have also been interested in mind machines since first reading about them in an article in Everyday Practical Electronics in the 1990s. I listen to binaural beats (sometimes isochronic) and swear they work, although that may be a placebo effect. Want to know more then just do a google, I may explain them in more detail later in the year. I have not experimented with light in relation to Binural Beats, Mind Entertainment or Relaxation (whatever you want to call it). Hence my second project is to create something that would allow me to create a controllable light stimuli to use on their own or with Binuaral Beats.

The hardware set-up is straigtforward for just light, but getting it to work with audio is another thing. The best way that I can see is to ahve the arduino create the audio as well, or to have it connected to a computer and let that control the LEDs via the Arduino. I would prefer the first so that it can be a self contained set-up. There is another aspect, which I will discuss later, but means the project will be split to two phases:

  1. Create a sound and light machine using an Arduino
  2. Measure the effectiveness of the machine

Create a sound and light machine using an Arduino

Like my other projects, rather than rush it I will break it down into small and simple steps:

  1. Create a pair of RGB LED goggles.
  2. Programme a simple, say 10Hz, demo and see what happens. There are several combinations here, have both LEDs on the same colour and switching at the same time, use different colours, switching differently, etc. I will have them both with the same colour and switching at the same time and will experiment at the end of phase 2.
  3. Research how to generate stereo audio. Probably use a DDS system as it only needs to be two sinewaves.
  4. Implement a binaural beat sound system. Fixed frequency.
  5. Possibly add switches and LCD to allow the frequencies to be changed.
  6. Add an input to allow an external audio source to be fed in, mixed with beat, and output to headphones.
  7. Add LEDs to flash at the rate of the beat.

Measure the effectiveness of the machine

As mentioned above I have used beats for a while and swear they work, I do not know if they do. I ahve read lots of blogs and research papers, but to find one that is not biased one way or the other and just uses pure evidence is difficult. I would like to investigate, as far as I can if they do anything, physically, at all. So what I would also like to do is to take measurements of the body to see if it does work.

So the question is what can be measured? Well I have already mentioned a pulse oximeter. That may or may not show anything. There are other things that could be used, a galvanic skin sensor, blood pressure, body temperature and brainwaves. Now blood pressure could be an issue. I have seen some designs for doing that without using a cuff, but that is something to look at later on. Body temperature could also be an issue, don't want something stuck in my ear, mouth, or anywhere else! So some of these could be useful but will be looked at later on.

At present to me the pulse oximeter and brainwave are the two best ones to go for. The brainwave monitor I will have a go at making myself. There is a very nice headset that would be perfect for this but far too expensive. So what are the plans:

  1. Test the Light and Sound Machine (LSM) using the pulse oximer with various settings (just LEDs, just audio, different frequencies, with and without external audio, etc.). I am expecting the heart rate to slow as you become more relaxed.
  2. Add a Galvonic Skin Response (GSR) sensor and repeat above test. Again I expect to see the skin resistance decrease as stress is reuced.
  3. Research brainwave monitors.
  4. Build and test simple brainwave monitor. Unless I win the lottery, this will only be a simple set-up, either using OpenEEG or a totally homemade set-up. The hope is this will show brainwaves decreasing as relaxation sets in and/or synchronising to the beat of the LSM.
  5. Research other metrics that could be measured. Well that is the plan.

Again f I get anything done or not is another question but first priority is to get the pulse oximeter sorted.I will keep this blog updated with all developments and will put code on Github.