A guide for a robot finger hack
I think people should more listen to their fingers. Why? you ask. What in the world fingers could tell you? well, a lot…
But first things first.
Half a year ago I went to a body modification studio and got a tiny little neodym-magnet implanted into my left ring finger. Besides pure curiosity, I was totally fascinated by the chance of new research topics coming out of that little body intervention. I thought and expected a new way of sensing more aspects from my environment, magnetically controlling some external devices like my smartphone and alike. But the possibility of actually transmitting audio signals via induction to the magnetic finger was surely not in mind at the beginning.
Since the grinder, bodyhacker, cyborghacker (or whatever other term you will find) community is growing bigger and bigger, remix and modification of modification culture within the scene is also becoming richer and richer. Did I say “richer”? yes, that brings me to the guy who inspired me to do the robot finger hack – Rich Lee. He implanted a magnet into his ear lobe, so that he can transmit audio information via a necklace directly to his magnetic ear lobes and can listen to music without earphones.
How does that work?
Basically it´s all about oscillations of the magnet, leading to a hearable event. To demonstrate that in a more tangible way, let´s first have a look how speakers work.
Good old Mr Faraday not only discovered his cage but also made his contribution that we can go to Berghain and enjoy some nice bass waves massaging our bellies. He therefor began to make experiments with electricity and magnetism, showing that every live conductor automatically builds up a magnetic field around itself. Now, if that´s the case that means that if current runs through the coil, the coil builds up the magnetic field around itself and since it is surrounded by a static magnetic field from the magnet it moves up and down in the rhythm of the audio signal (current). Having the coil connected to the speakers membrane, this vibrating movement is exactly what you hear when the vibes coming through the air to your ear (or belly). Great!
Finger magnet producing sound
In the speaker example the magnet always stands still and the coil is the vibrating element. With the finger hack it´s the other way around. Here you have the coil standing still (i.e. around your neck or your wrist) sending the vibes (electromagnetic waves) to your loosely floating magnetic implant (whatever site of body). The magnet grabs up the waves and vibrates like the coil in the speaker example and yes, YOU CAN HEAR IT! (even if it´s not comparable with berghain sound, it´s there).
Robot finger hack
Now it´s only a small step further to develop some fun stuff to get your finger speaking to you in whatever way or mode you want. I prefered a robot voice coming out there. If you want to build it yourself, here´s the schematic to do so.
I simply used the HT8950 Voice Modulator IC (the 16 Pin version). It´s a chip which provides several steps to shift the frequency of an input voice, producing a vibrato or robot effect. There is also a built-in microphone amplifier included, so you can easily “speak” with it. Then it´s just about to connect it to an amplifier. Depending on the gain you would like to have (options between C10 and PIN8 of amp are: 1,2kOhm for gain = 50, bridge it for gain = 200 [recommended] or remove it completely if you´re fine with a gain of 20) you should also consider putting a small heat sink onto the LM386. Use thermally conductive paste if you want to do so. I haven´t used it for a longer period of time but you´re better off if you give the IC more surface to breathe. Connect a 9V monobloc battery to it, get your coil connected (I made 30 winds) and listen carefully what your robot finger tells you – like for example these guys: video