I have an old brain machine - a Synetic “Esprit” ‘Computerized Relaxation and Mental Fitness System’ that still works. It has 12 Presets and a very simple interface 4-button/6-LED project box interface. It uses a sunshades with four small ganged LED’s per eye and a pair of stereo headphones (any set works fine). I want to recreate the brain machine shown here, but using my existing ‘eyephones’ and headphones.
I bought two stereo headphone jacks that fit the eyephone and the head phone plugs.
This one was confusing enough that I decided to check out the stereo plug on the eyephones to see what works to light up the LED’s. It turns out ground has to be in two places at once to light up both arrays when I test the plug directly, but that doesn’t make much sense to me. This looks a little like charlieplexing, so should I use a third pin instead of ground? I know both eyes on the eyephones blink sometimes in tandem and sometimes alternately when used with the “Esprit”, so that functionality should be surmountable with the arduino. If someone give me a hint or two about how I need to interface this with my pins so the output from pin 12 goes to the right eye only and pin 13 to the left eye only, both at the same time or alternately according to my preferences, I would be grateful.
These work, but not exactly as expected. For this experiment, I’m the ToneTest from the Arduino Tone library exactly as is. I’ve put one of the stereo jacks on the breadboard. The center pin is ground. The left jack pin goes to arduino pin 12 and the right jack pin goes to arduino pin 9. If I play ‘a’, I can hear 440 a coming mostly from the right ear. Play ‘s’ to stop. Then play ‘A’, and I hear it mostly in the left ear. Play ‘S’ to stop. Then play ‘a’ and play ‘D’, and you can hear two tones louder and in both ears. In both instances, I’m hearing bleed-through, where the sound from one speaker can also be heard to some extent on the other speaker. I was hoping I’d be able to get just pin 9 out of the right ear and just pin 12 out of the left ear, without combining. When I remove the wire from the ground pin on the arduino, the sound is equally loud in both ears. I would have thought the sound would have stopped, since the circuit technically has no ground.
How can I make it so the sounds coming out of each pin are truly isolated from the sound coming from the other pin?
These are the things that