Wireless wires

Easiest way to wirelessly send a one or zero.

Similar projects worth following
Sometimes you want simple wireless capabilities in your project. I'm talking about situations where you just want to engage an actuator or read a "high" value from your sensor across the room. If it is a relatively short distance and only one bit worth of data do you really want to pay (the time and money) for Bluetooth or WiFi?

Of course not!

Use, instead, a wireless wire.

3 pins: Gnd, Vcc, and I/O. If the I/O goes high the wireless wire emits a signal just outside of the audible range. For any other wireless wires in the vicinity If a signal of the correct frequency is detected the I/O goes high.

Here is the great thing: you don't necessarily need two wireless wires to make use of it. Since all smart phones (tablets, and most computers for that matter) have both speakers and microphones you may only need one.

  • 1 × LM567 Tone Decoder Application Specific ICs / Telecom ICs
  • 1 × Piezo Buzzer
  • 1 × MAX9814 Audio ICs / Audio Amplifiers

  • Software

    Chad Grant08/19/2014 at 23:23 0 comments

    My goal is to make the wireless wires without an embedded processor.  My reasoning behind this is to keep cost and complexity down - plus who wants to deal with upgrading firmware on these.

    One of my main motivations for making this device, though, is to use it in conjunction with my smart phone.  I can think of a lot of situations where my phone will be the receiver/transmitter and the other end will be some sort of device that employs a wireless wire to communicate with me (it's only communicating one bit - anything more and I'd move to Bluetooth or WiFi, of course).

    To that end I'm planning on writing an open source android library that can be used to both detect specified tones from the microphone, and emit them from the speakers.

    In the future desktop compatible libraries may also be considered.

  • Interference

    Chad Grant08/19/2014 at 23:15 0 comments

    A question was posted on how interference will be handled.  It is a good question.  When watching the video I posted it looks like my voice is causing interference with the (almost) ultrasonic tone.  I think what might be happening in the video is the microphone amplifier that I am using in the proof of concept (MAX9814) has automatic gain control which is amplifying my voice and attenuating other frequencies - including my 18k tone.

    I believe that moving to more appropriate hardware for these ultrasonic tones will alleviate this problem.

    Another problem to worry about is what happens when the tone that the receiver is listening for is being generated by something else in the vicinity.  This could be handled by providing access to a trim pot that would allow users to select a different frequency.  The problem, though, is that the transmitter would also need to be adjusted.  This would get tedious very quickly.

    A solution that I am currently leaning towards is having the wireless wires require/emit two different ultrasonic frequencies.  Both need to be detected by a receiver in order to turn on, and when a transmitter is set high both will be generated.

  • Voltage Regulator

    Chad Grant08/19/2014 at 03:32 0 comments

    The LM567 tone decoder, which I'm considering using in this project is a Voltage Controlled Oscillator (VCO).  As such, to have a paired transmitter and receiver you either have to have a pot to tune each side, or regulate the supply voltage.

    For ease of use I want to avoid having to tune the circuits.  I also don't want to limit applications by requiring both the receiving device and transmitting device to be running at the same voltage.  So I'm planning on using a voltage regulator that can supply all of the wireless wires with a fixed voltage, regardless of the device they are being used in.

  • Transmitter Details

    Chad Grant08/17/2014 at 03:02 0 comments

    I was generating some lower frequencies with the transmitter while looking at the spectrum analyzer app and noticed that there was often a harmonic frequency generated.

    This makes sense because the LM567, when configured as an oscillator, makes a square wave.  I verified this with an oscilloscope.

    In later version I will see if I can convert that square wave to a sine wave.

  • Borrowed Oscilloscope

    Chad Grant08/16/2014 at 21:36 0 comments

    I borrowed an oscilloscope so I could take a look at the output I was getting from the microphone.  I was originally using the MAX4466 from Adafruit.  At lower frequencies I was getting a fairly well defined waveform, but as I increased the frequency it would soon disappear untill all I could see was noise.

    Luckily I had also purchased the MAX9814 that has built in automatic gain control.  With this amplifier I was able to see frequencies up to about 18k.

    The amplifier is giving me about 300mV peak-to-peak at this frequency - but my transmitter is only 4 inches away.  I'm thinking I'm going to want to use a circuit/amplifier that is specifically designed for 18k-25k Hz range so that I can get a little more distance between them.

View all 5 project logs

Enjoy this project?



Dylan Brophy wrote 07/05/2017 at 05:37 point

This is actually really cool!  I'm glad I found this.

  Are you sure? yes | no

paulcena4 wrote 02/11/2016 at 21:57 point

Really a great piece of innovation, whats your favorite way of remembering your creations, I get them printed on my tshirts, from The Best Tshirt Printing In Los Angeles that really makes them special to me and I never forget them. Might look silly but its how I'm haha...

  Are you sure? yes | no

atuatsu42 wrote 01/26/2016 at 21:44 point

This is really a masterpiece I did a show once on, in which I explained the audience almost a similar type of device, pretty complex stuff though we tech geeks coin it in a jiffy, but for casual persons it's extremely difficult to understand the techs involved! great work by the way fabulous indeed!

  Are you sure? yes | no

sam329672 wrote 07/02/2015 at 13:28 point

Reminds of my knife project when I transformed a fixed blade knife into a wireless
antenna, was my very first innovative creation, after that I have cruised
and that seems a pretty slender achievement now but it was pretty special
at that time, good work buddy nice innovation it must have been difficult to
execute and mastermind due to the delicacy kudos for you, below is the link
this is the knife that I transformed into antenna, pretty wicked isn’t it?

  Are you sure? yes | no

Robert Key wrote 08/16/2014 at 06:41 point
The wireless wires are amazing, their performance is so smooth and flexible, it's amazing how technology is growing day by day and is reshaping our lives and making life for mankind pretty versatile and comfortable.

Robert From---

  Are you sure? yes | no

Chad Grant wrote 08/16/2014 at 19:08 point
Thanks Robert.

  Are you sure? yes | no

aelias36 wrote 08/15/2014 at 04:34 point
If it's just outside of the audible range, couldn't many sounds cause interference?

  Are you sure? yes | no

Chad Grant wrote 08/16/2014 at 19:06 point
That's a good question. I walked around my home and office with a spectrum analyzer app on my phone, and was able to see some higher frequencies present, but normally not too many - it mostly looked like white noise.

Some strategies that I will look in to for handling interference problems are:
- Setting up a narrow bandwidth for the target frequency.
- Requiring/emitting two or more (non-harmonic) frequencies.

  Are you sure? yes | no

Similar Projects

Does this project spark your interest?

Become a member to follow this project and never miss any updates