My Second Implant

by Estragon

My first implant was really not a big deal.

Getting it was about as complicated as getting an ear pierced.  It is a small inductive microphone implanted in my throat.  It's basically just a throat mic, but permanent.  There is a lot of space between the muscles and sinew of the throat, so the implant was able to include a transmitter about the size of a grain of rice, a piezoelectric film attached to the outside of my esophagus, and a small rechargeable battery.

Because the piezoelectric film actually generates electric current as it responds to the vibrations of my voice, I can keep the battery charged indefinitely just by speaking and eating.

Some people are getting these microphones implanted in their lip or somewhere around their mouth, but this isn't nearly as good for sub-vocalizing.  Also, they tend to get impacted with food particles, and pick up sounds from the environment (including breathing and eating).  The advantage, though, is that they pick up sounds from your real voice.

For the induction mics to sound more like you, some digital signal processing is needed.  This is done by a tiny radio receiver which, in turn, connects to your cell phone or other devices via Bluetooth or something similar.  The implanted mic has no computing power at all - it's just a miniature, low-power radio transmitter hooked up to a microphone.

Anyway, this implant worked just fine, and still does.  I can sub-vocalize commands to my computer, speak on my cell phone, and make recordings of spoken notes.  The radio transmitter is good only for a few feet, so surveillance is really not much of an issue.  If you're close enough to pick up the radio signal, you're close enough to see my lips and throat move, and probably hear my sub-vocalizing.

Implanted microphones like these are pretty common these days.

Although you can't yet get them at your local body piercing shop, you can buy kits on the Internet, or find some doctors to do the implant.  Personally, I decided to get mine from one of the original sources, Yongsan Electronic Village in Seoul.  It's not even a back room thing there; it's more like a barber shop.  You lean back in a chair, get some local anesthetic, and boom: you're walking out with a small bandage on your neck, and in your hand is a combined receiver and digital signal processor the size of a half-dollar coin.  Make sure you get a couple of receivers set to your radio frequency (and write down the frequency somewhere!), in case you lose one.  It was less than $200, though I hear you can get some Chinese-made models installed for $125 in Greenwich Village.

I guess I'm avoiding talking about the second implant, since the first one is so sweet.  In fact, you probably guessed already that I'm speaking this whole document into my computer right now, sub-vocalizing to my microphone implant.

Consider that the throat implant is basically just a very small transmitter, sort of like those mini-spy mics you still see advertised in electronics magazines.  It turns out that receivers can be a lot more complicated.

For my second implant, I wanted to pair my microphone with some speakers.

When you think about it, this makes sense as the next popular wave of human-machine interfaces.  There are literally billions of cell phones, MP3 players, and similar devices in the world (this is several times greater than the number of computers).  When we were tired of walking around holding our cell phones to our ears to talk, we got wired headsets.  Then we got wireless headsets, based on Bluetooth or something similar.  The obvious next step is to have a permanent speaker installed in or near the ears, that can communicate wirelessly with phones, computers, or other devices.

This isn't without precedent.  There has been some cool technology for deaf people for a while, but it's pretty kludgy and custom.  One technique is to use bone induction to help deaf people to hear.  A more mundane technology is the common hearing aid, whereby people who are hard of hearing can get custom-fitted aids that go into the ear canal, amplifying what is heard.  These devices consist of a microphone at one end, a speaker at the other, and some electronics for the battery, volume control, and sound processing.

Did you know that leading-edge quality hearing aids can cost thousands of dollars each?

Compare this to under $100 for a really good Bluetooth headset for your cell phone.  Well, as you can imagine, some entrepreneurs are working to make in-ear speakers the next big thing.

I thought my first implant was bleeding edge, but this second one wasn't even being mass produced yet.  I had a contact - a fellow graduate student who came to my school after graduating from Beihang University in Beijing, China.  Beihang used to be known as the Chinese Defense University, and they have some way cool technology there.  It's sort of a mashup of a high-tech university, such as Caltech or MIT, with a defense industry lab, like in the old James Bond movies.  I don't want to get anyone in trouble, so let's just call my contact Benny Li.

Benny did his undergraduate degree at Beihang, with dual majors in electrical engineering and computer engineering.  He spent a lot of time in the lab where they develop microcircuitry for things like those tiny electronic spying insects.  Benny said that actually getting insects to fly has been really hard, due to the energy required and weight needed for, say, a robotic fly.  But they walk and crawl just great, and can transport themselves by piggybacking on unsuspecting human carriers.

To make a long story short, when Benny heard about my first implant, he got one too.  It was during a trip home to China over winter break, and he never told me exactly where.  His implant worked just like mine, except his radio signal was encrypted.  How encryption of the radio signal happens in a transmitter the size of a grain of rice is beyond me, but maybe his transmitter is bigger than mine.

This first implant got us talking about our desire for in-ear speakers.  The basics aren't too hard.  You can either use a vibrating surface to make a regular speaker that pushes air around (thin metal sheets, or paper, or whatever), or rig up something similar that impacts the bones of the ear canal or eardrum.  But the details are a bitch.

First off, you don't want everyone hearing what you are listening to.  So, that rules out a regular speaker placed in the outer ear canal, like those in-ear ear buds or hearing aids.  We wanted to be stealthier, and not have it obvious to an observer that we are wearing speaker implants.

Placing a speaker deeper inside the ear canal could work and, in fact, there are some hearing aids that work like this.  Our dear, lamented President G.W. Bush supposedly used these all the time while he was giving his speeches, so that a remote person could prompt him with things to say.  But these aren't permanent, can be uncomfortable, and tend to muffle outside sounds since they don't have built-in microphones like regular hearing aids.

The plan we arrived at was to place a small Bluetooth receiver and battery subcutaneously, just behind the ear on the outside of the head, but connected with very thin wires (also subcutaneous) to an induction speaker deep in the ear canal.  The Bluetooth receivers would be generic items, about the size of 5V voltage regulators and available from places like Mouser.  Another thin piece of piezoelectric film would let the battery charge whenever the wearer chewed food.

So far, so good.

Since everything would be under the skin, it wouldn't get wet, and wouldn't get moved around if I scratched my ear.  Yes, clearly I was thinking I would be the person to test this new gizmo we were dreaming up.  The induction speaker would rest right on the bone of my inner ear canal, and would cause me to hear things through my eardrum, but nobody in the room would be able to hear what I was listening to.  We decided to leave volume control to the transmitting device (capped to an equivalent of no more than 100 decibels, for safety).

This was just dreams and schematics, but then Benny went home again for spring break.  When he came back, he said he had a surprise for me: his friend from Beihang would be visiting and would implant the prototype, if I wanted to try it.  Of course I did!

This was a lot more intrusive than the first implant, and left a lump behind my ear where the receiver was.  I opted for general anesthesia, but the whole operation took under an hour.  Once I healed, I could barely feel the wires as they went into both of my ear canals.  But the fact was, it worked great!  I could pair the Bluetooth receiver with my cell phone, computer, and MP3 player, and use the first implant as a microphone.  It also wasn't dangerous to wash my hair or get water in my ears.

No, I didn't get an infection or develop an allergic reaction or anything like that.  Benny's friend who did the surgery, who I'll call Jing Yu, was also a grad student, but he had done a lot of work on experimenting with microelectronics implants in lab animals.  I asked him if this was for stuff like turning hordes of rats into surveillance drones, and he said it was something like that, but didn't elaborate.  Well, even if I was a lab rat, I could at least enjoy some tunes in the privacy of my own head.

It went well for a few months, and eventually Benny got his speaker implant, too, during another trip back home.  Just for kicks, we used it once to cheat on an exam.  I sub-vocalized the questions to him, and he gave me the answers - all with my cell phone hidden innocently in the bottom of my backpack.

So what went wrong?

Well, I guess I should tell you what I'm studying at grad school.  I don't want to give enough details to get me or my advisor into trouble, though.  Let's just say that I'm studying communication, specifically for orbiting satellites and, someday, interplanetary spacecraft.  My advisor has grants from NASA, but my tuition is actually paid by a grant from DARPA.  Yes, I'm studying to be an actual rocket scientist.

Anyway, what happened was that my receiver implant was a little more capable than I expected.  It has a microphone, not just a speaker.  In addition to pairing by Bluetooth, it connected to any open wireless access point and opened up a TCP/IP connection back to a system somewhere behind the Great Firewall of China.  We found it was able to use WEP- and WPA-enabled access points at school and in my apartment, too.  In a nutshell, everything I heard and said, for months, was streamed live to someplace in China.

I might have never known, except that one day in the lab my advisor got a phone call from his DARPA sponsor.

It seemed that the algorithm I'd worked on for spread-spectrum communication with ground- or space-based devices was detected on the new Chinese telecom satellite that went up earlier that year.  My advisor had provided DARPA with the source code and a paper that he and I had worked on, and I can remember several times we had had detailed technical discussions about it.  Plus, I had been in the habit for months of dictating my papers and emails by sub-vocalizing.  The spooky part was that this all happened within a few months after getting the second implant.  Even DARPA said it would be years, if ever, before they put the algorithm to use for their own purposes.

While my advisor was on the phone, I didn't know whether to be flattered or scared, but I kept my cool and didn't reveal my growing nervousness.  That weekend, I got another grad student friend to spend some time with me in a Faraday cage with a multispectral receiver and spectrum analyzer.  We figured out what was going on.  Benny swears he didn't know.

I was physically infected by this implant, and turned into a human network zombie.  We finally got the thing turned off by carefully snipping the wires from the receiver (and, I now know, transmitter!) to the battery.  This hurt like hell, but I won't feel comfortable until I find someone to surgically remove the whole thing.  Until then, I'm back to my regular Bluetooth headset, which I now keep wrapped in aluminum foil when I'm not using it.

I don't know whether there's a clear message or moral in my story, but I wanted to share it with you.  Partially as a warning to readers about the potential dangers of new technology, partially to brag that I was the first kid on the block with implants that, someday, will be as common as wrist watches, and partially to try to inspire entrepreneurs and inventors out there to get this type of thing working better, and at a good price.  Hell, with two billion cell phones in the world, there's a huge market to be tapped.

Next, I've gotta get some cameras installed in my eyes.