D102-3 Comments Expand

This is a conversation under article D102-2 Silent Sound Demo schematics, circuit and operational theory documents

These look like good introductory circuits. Another good intro project is to make LEDs flash at 4-40 Hz brainwave frequencies, which causes the brain itself to resonate at those frequencies.
Mounted on sunglasses, with a fancy case, these 555-timer based circuits sold for up to hundreds of dollars in the late ’80s and early ’90s.

The true “silent sound” technology is more complex than what is shown here. It uses two ultrasonic emitters of nearly the same frequency, with the instantaneous difference in their frequencies being set continuously by an arbitrary audio source.
The two highly directional “silent” ultrasonic beams are aimed so that they only converge and overlap at the target, where the “beat wave” of their frequency difference re-emerges as audible sound.
The effect of this is to make the sound only appear at the target, “throwing the voice” like a ventriloquist while the actual speakers seem to be silent.
It doesn’t reproduce low frequencies well, such as are needed for brainwave entrainment (synchronization), which would also require two SS devices for stereo, a pair of emitters located on either side of the subject.
They can be used for sending subliminals (but are not as good as regular sound sources). Their main potential use in mind-control is making people think they’re going schizophrenic.

That kind of silent sound isn’t introductory hobby-level stuff. But there is a lot of impressive and useful stuff one can do in electronics while working up to that level.

Some advice for getting started in electronics:
you need a budget of at least a couple hundred dollars, several hundred is better (Unless you just buy circuit kits, generally not recommended for real learning. Exception: the “150 in one” (or some similar number) -type kits, which can be wired up as many different circuits.)
have at least two decent multimeters (volt/ohm/current). Most have only spike leads that require you to hold them against the wires – slip-on attachments with little grabber hooks are available, allowing using
have a solderless breadboard (not good for high frequency, but better than chip sockets for prototyping)
solid-core wire of compatible size for the solderless breadboard and wire-stripper tool
an oscilloscope is a big help, cheap ($40-$200) USB scopes adequate for audio and even low MHz frequencies are available, Ebay has surplus scopes for reasonable amounts. (Tektronix or HP are best.) You need probes for ‘scopes, they aren’t as cheap as one would think.
Get and study the “bible”: “The Art of Electronics”. 2nd ed. (’80s) is ok, there are pdfs out there.
For basics, Forrest Mimms’ books are the best, starting with “Getting Started in Electronics”, also his books on op-amp and 555 timer circuits.
You need sets of the common values of resistors, electrolytic capacitors (+a bunch of 0.1 uF if doing digital chips), and film (polyester/ Mylar) capacitors. These are available as sets from electronics supply houses.

• By far the most versatile active component is the op-amp. Most of the time any standard modern op-amp can substitute for any of the triangle-shaped things in schematics, e.g. the 741s shown in the article’s schematics. The 741 is really ancient, one of the first op-amps.
  Today you can get excellent op-amps for a few cents each. The Texas Instruments TL074 is a good choice for most circuits.
  These, like most of the old DIP packages, (the ones shown in the article that will work with solderless breadboards or sockets) are best sourced from surplus dealers, e.g. Electronics Goldmine (US). China no doubt has its own such dealers.
  Nevertheless, there are hundreds of different types of op-amps, which have different capabilities, about which whole books have been written.
  Try to verify when substituting that your op-amp can handle at least the power and frequency needs of the circuit, using the datasheets or online selector at the manufacturer’s site, but for simple circuits it’s easiest to just wire it up and see if it works.
  Search online for: “op-amp circuit collection pdf” – there is hardly any analog circuit that you can’t make from op-amps.
• you’ll probably need a few other things for most circuits: some diodes (type generally doesn’t matter, except for high- power, get a bag of misc.
  surplus small-signal diodes), and transistors (typically bipolar pnp and npn -types, the 2222 and 3904 being the most common of those respectively), a 4xAA battery pack with leads is useful, a multi-voltage power supply (power brick type, a good bench PS ca cost hundreds), a couple of 9V snap-on leads is quite handy
  the 555 “timer” (it’s a bunch of things, really) is another very versatile component, and a mainstay of hobbyist circuits. They are great for making oscillators of a wide range of speeds, including for making audio tones and for slowly blinking lights.
  it’s good to have on hand some solder-type breadboards for permanent circuits, soldering iron, lead-free solder, extra iron tips, project-box enclosures, etc. etc. It all ads up, though.
  Radio Shack shutting down was a blow to the hobbyist, now one has to wait to have each little thing shipped.

Yes. “The Art of electronics” is a true classic. I would respectfully suggest you read my article “Mad Scientist Explorations”. I think that you would love it. In fact, I urge everyone to read some of my older articles. Don’t let this jewel slip into the cracks.

Great article, thanks especially for the electronics surplus sources. I saw you mentioned the RadioShack Engineer’s notebook series – those were all done by Forrest Mimms, who is still around, with his own site.
(I see Amazon wants about $130 for his Getting Started in Electronics; it’s $20 from his site.)

Back in the early ’90s (IIRC) Forrest was going to take over the Scientific American Amateur Scientist Column, which you also mentioned, until they found out he wasn’t a Darwinist fundamentalist and withdrew the offer. A real shame, Sci Am has gone steadily downhill since then.

I just found that my favorite mad-scientist book when I was 12, a 1960 collection of ’50s Amateur Scientist columns is available online free: https://archive.org/details/Projects_for_the_Amateur_Scientist_Scientific_American/page/n1/mode/2up . I really, really wanted to build the Van de Graff particle accelerator, but my parents didn’t know any metal-spinners or glassblowers, the high-vacuum pump needed rather a lot of mercury, and even the blase ’50s writers noted it might have a tendency to explode.
Not a downside to a 12-year old!

I should add that electronics has moved on from these types of circuits to microcontroller-based ones. For hobbyists, the Arduino and “shield” add-on boards are most popular for embedded circuits.
The Raspberry Pi line of development boards are high-powered computers running Linux that can also control their “GPIO” lines for connection to a solderless breadboard or other circuit. For motor control, the “Beaglebone Black” is superior to the Pi.
(Hobby King is a great source of cheap servomotors, also high-power lithium batteries, power controllers, and motors). The linuxgizmos.com site covers all the development board / single-board computer (SBC) releases, there are hundreds.
Many have useful features such as accelerometers / gyroscopic sensors, camera inputs, display outputs and more. Beyond features, one should look at the quality of the documentation and the activity of the user community, since that is generally the only support.

Using a microcontroller board with built-in DAC (digital to analog converter), one can produce any arbitrary waveform at will, at whatever frequencies or spectrum of frequencies, which replaces most of the older circuits.
Even without a DAC, toggling a digital I/O line rapidly (pulse-width modulation) through a capacitor (to smooth the voltage) gives the same effect as a DAC.

Most microcontrollers also have ADCs (analog to digital converters), which allow measuring the voltages on several different wires millions of times per second, converting the waveforms on those wires to digital form.
The combination of ADC, digital processing and DAC allows a microcontroller to emulate essentially any circuit of any complexity, and to do things that would be difficult or impossible to do with analog circuits.
The cost is that one has to program the microcontroller to perform the functions one wants.

Analog circuits are still needed for higher speed / lower-latency in some situations, to make inputs conform to the voltage / current / power limits of the microcontroller, and to produce higher voltage / current / power from the microcontroller’s outputs.
Power and radio-frequency (RF) are also still analog, though usually with digital monitoring and control.

I might ask you to help design the intention control system that these preliminary schematics point towards. Are you game?

Sure, I’ll try to help – how much I can help will depend on what you have in mind, of course.
For a system to be used on oneself or to create audio files for distribution, it seems to me that a software solution would be best, a program that takes an audio input (music or whatever) and mixes it with another input (suggestion track) which is optionally processed in various ways (FM, speed, pitch, amplitude etc.), to create an output which can go direct to headphones or be recorded to a file.
More advanced would be to have the subliminal track’s volume regulated relative to the main audio, so it is a constant dB lower.
Adding hemi-sync processing (shifting one stereo channel by a few Hz to create a brain-entraining beat-frequency at a target brainwave frequency) would also be fairly easy and should make it more effective.

I’m not convinced that making suggestions more subliminal or scrambled makes them more effective, rather, I think they work best if they’re barely audible / understandable if one concentrates.
Simplicity, vocal tone, rhythm and repetition are most effective to speak to the subconscious.
(NLP has a lot of applicable techniques for crafting effective non-subliminal but covert messages, but they can’t be automated.) So far as I know, not much practical testing to optimize subliminal technical methods’ effectiveness has been done.

Have you looked at the Mindzoom software? It does just about all of that. http://www.mindzoom.net

Correction: I meant Beaglebone Blue for motor control.
>https://beagleboard.org/blue

Among many other features:

• 8 6V servo out, 4 bidirectional DC motor out, 4 quadrature encoder in // Sensors: 9 axis IMU (accels, gyros, magnetometer), barometer, thermometer

Great for robots, UAVs, CNC machines
currently $82 at Mouser