So, after testing the sensor, I decided to give up the idea of using lights and turn to a different medium. Ideally, if we have the frequency detected, then we can trigger different colors based on frequency range, but with the current readings of this sensor, we get numbers within a range, which we can still divide and define its range within itself, but the end result isn’t significant at all, especially while reading all bands together, so I decided to move to sounds, for 2 reasons: a) We can actually hear the pulse of the bandwidth directly, if we connected the output to an amplified speaker, and b) With the current output behavior, it will be more interesting to use this data to generate tones or build sounds, it will be more interactive. So, now instead of adopting the notion of seeing is believing, the project is moving to the idea of literally: Giving voice to the unseen!

Below is a sample video of translating sensor readings to tone. The melody in the video is constant, given that the sensor isnt moving or affected by anything so readings are almost constant.

Now for remaining 3 weeks, I need to work on different wearable with embedded antennas that correspond to different bandwidth. The GSM 900Mhz antenna can be triggered by phone, am now finding ways to trigger other frequencies. One option could be to make twin pieces that work together!

I made a quick mock up for the wearable and the embedded Bi-Quad antenna, and more to follow:

Quick paper mock up to demonstrate size and usability. Next is applying over a mesh material

Resembling a bow-tie, the Bi-Quad antenna works interestingly as part of the item.

900Mhz antenna field outline demo

So, now we know that in order to build the sensor we need an antenna and RF amplifier piece, but first we need to specify what bandwidths we are talking about, in order to specify our selection. I chose to go for apps from 500Mhz to 3~5 Ghz, given that that is what most of the current technologies depend on, and so they do have lots of ambient presence. The web is full _FULL_ of tutorials on how to build an emf sensor with arduino, and using a piece of wire as a probe. Well, it is definitely sensing something, probably some low frequencies and noise, but this is not accurate and isn’t what we are looking for. There is another piece that is trending all over the web, which was first tried by a German researcher in a media lab in Cologne, then virally continued to expand, it is currently being used by Google data labs and is also being part of other interesting research with mobile apps. The good things about this chip is that it is not difficult to implement, but the cons are that it is not very accurate (its sensitivity is -60 dbm, while we need -110 dbm). In general, there is no current available RF chips that has sensitivity over -75dbm for frequencies above 1Ghz. So, the sensitivity issue will always remain a problem, for now. There are solutions for increasing the dynamic range to -95dbm using different amplification, but still, we will missing the remaining power difference.

I built the sensor chip and tested it, in order to get a sense of how data would look like and how sensitive it is. I tested with different antennas for 2.4 Ghz (which is Wifi Frequency), well, the fractal antenna seems to do better, but still, nothing is incredibly sensitive.

So this is a video of the sensor working with a wire loop antenna for 2.4GHZ.

And my story with fractal antenna goes long:

Milled antenna (well, machine focus isn’t awesome with large boards! )

Copper sticker was faster to implement

This is an ongoing trial for weaving an antenna or making crochet antenna. Looks crazy, but worth trying!

So, how does that work?

Well, it is like we need to talk to the wave in order to interact with it, and the way how to grab its attention is the antenna. There is a relationship between antenna design and the bandwidth, so what works for GSM doens’t work for FM etc..and since we are talking about ambiant radiations, so we need to talk to different bandwidths, where each needs different solution. Below is a little block diagram of how the process should go:

So, we need an antenna that corresponds to the bandwidth we are addressing, then we need a piece of electronics (RF amplifier that transmits and output voltage that corresponds to the field intensity), then we need to do something with this voltage coming out, so that it is representative enough in terms of visualization. Clear?

Until that point of research, I was still focused on the idea of _seeing is believing_ and in that sense we need to figure out a system that depends on triggering lights or any other seen effects, so I was thinking on one of the below applications, I sketched other ideas related to augmented reality and car antenna, but things radically changed, as time went by

Research Phase I:

The purpose of this research is to find ways to interact with electromagnetic waves. Visiualize them. Hear them, any method that would give voice to this unseen which defines our daily lives.

I have an interest the unknown and I like to be surprised. In the beginning of the research phase, I outlined a few topics_as thinking out loud _ then I decided to follow my passion and dig more into electromagnetic waves subject and see where it can lead to, and if it would eventually link to application of data mining (which was my second research proposal)

It has been a long journey of research, where my general knowledge about the field wasn’t much experience in the field wasn’t much in the beginning and my technical expertise in measurements was almost nothing. Nada!

Below are some aspiriation and how my learning process started, bit by bit from experiments carried out in 1800s all the way to the most recent and tiny gadgets. And the story goes long as the need for waves detection is mostly bound to commercial application or military research, which defines a lot of capabilities of what could be done and what the technology can offer at the moment.

0. Tesla’s basic application:
Tesla’s coil is used to produce high voltage, low current and high frequency AC. In practice, it is not a direct application of waves visualization, yet it creates a strong and vivid evidence of charges!

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