INTROImagine you could take 7 old Amiga 500 computers, Amiga 1200's would be even better, and connect them in parallel in order to create a magnetic rod which rasters scans through a central scanning area in order to see the electromagnetic structure of the human body. Herein I will share complete plans on how to build such a system. No kidding, I'm going to show you how to make a brain scanner with old Amiga computers! MRI machine cost millions, I'm going to provide complete details on how to make a machine which offers realtime video of the bodies electromagnetic structure.
A LITTLE ELECTROMAGNETIC THEORYTake a loop of wire shaped like a circle and apply a voltage potential to the ends of the wire and we produce a current through the wire. The electrons, flowing in a circle, create a magnetic field which extends out of the circle, the most basic electromagnet. If we loop many turns of wire we multiply the strength of our magnetic field.
If we make two such electromagnets and orient them on the same axis, we produce a vector addition of magnetic fields. Essentially, we end up with a 'Saint Andrews cross' shape, or an X, where each line is a separate electromagnet. Because the fields add by vector addition, when we adjust the voltage applied to our loops of wire, we can point the magnetic field to any point within the angle of the X, extending out through the matter in front of it.
At infinity, the furthest point from the electromagnet, a magnetic field decreases quicker than the usual 1/d, we may refer to this area as the 'infinity point'.
We arrange 8, or 16, 32 or so, equidistant magnetic X shaped transmitters around the circumference of a perfect circle thus pointing multiple magnetic fields at the same point at the same time.
Each transmitter is thus capable of aiming its magnetic fields at all the points within a certain circle in the center of our scanning area.
Let us, for the sake of explanation, focus all our magnetic fields at the center spot. For this, each coil of wire will be driven with the exact same voltage, and current. Each magnetic field propagates through space towards the center. At the furthest point, the center, the magnetic fields decay quicker than normal, and all of our infinity points collide. Due to the nature of magnetic fields adding by vector addition, the geometry of the system cancels out all the extraneous magnetic fields in the intervening matter. The resultant field strength, of all our transmitters combined, has thus concentrated the magnetic field energy upon the central spot. We have created a rod of magnetic energy at a distant point in 3-dimensional space.
If each transmitter is wrapped with a coil, and each of these receiving coils is connected in parallel, the receiving coils will sense the magnetic field strength as determined by the distant point. The 'permeability' of the atoms, chemicals, or neurotransmitters, which our magnetic infinity point resides in will determine the magnitude of the output field.
Finally, we need to move our rod of magnetic energy through space in order to create television like video images. Each transmitter has 2 transmitting coils, so each one must be driven by 2 amplified 'video waveforms'. Each waveform is created such that all transmitter pairs point at the same point at the same time. Conceptually, this can be hard to envision, but the process is simple. Like a television, we choose to scan in a raster fashion, from left to right, one line at a time. The angle from each transmitter to the moving spot is calculated and the appropriate vector sum is stored in video memory. Each waveform, for every transmitter, is output, through high current amplifiers, simultaneously; thus moving our magnetic rod of energy through space in realtime, at television like frequencies. We calculate the waveforms required for each transmitter to hit our moving spot:
CONNECTING AMIGAS TO PRODUCE OUR WAVEFORMSIf we genlock 6 Amiga computers we can have 18 channels of simultaneous video output, we only need 16 to drive our scanner with 8 dual-loop transmitters.
The above genlock design carries the required video sync signals to 6 Amiga computers. In addition, the mouse port is carried through to allow GUI control of all Amigas concurrently.
The video ouput of each Amiga is connected to a custom video frequency amplifier, which plug into each other and the genlock board: (video amplifier x6)
We use a helpful diagram to help us connect the 6 Amiga computers to the appropriate transmitters on the scanner:
Every transmitter must be driven by the correct waveform such that each one points to our moving magnetic rod. Each Amiga will appear to produce rays of light which extend off the edge of the monitor.
We connect all our sensors, wrapped around each transmitter pair, in parallel, which effectively multiplies the output signal:
We then amplify the output voltage to approximately 1V peak to peak. We feed this output with our 'video sync' directly to a computer monitor with minimal processing. The system thus produces video frequency data automatically, which can easily be viewed and recorded. The more transmitter/receiver pairs, the more precise the system can become.
Every transmitter helps to fine tune it's co-operative partners. The overall distance to each point is a constant. As you move away, from the left, you move closer to the right. Every element, from electric metals to sodium and potassium, have a different magnetic field permeability. The resulting video frequency output will display realtime images of the bodies electromagnetic structure.
We can calculate the expected output values for every element found in the table of elements:
We can use any computer language to create the correct video display on each Amiga computer, I used assembly language allowing total control of the Amigas. Amiga 500's, running in HAM mode, allowed only 4 bits of resolution for each half-transmitter, Amiga 1200's would allow 6 bits for increased output resolution. Modern video hardware could offer 16 bits of resolution across the horizontal section, the images would be miraculous.
I assembled my 6 Amiga motherboards into a rack system with the 'master' Amiga located above them:
The same code can run on all 6 Amigas, all you need to change is the location co-ordinates for the transmitters which that Amiga is driving. You can find the actual working 68k assembly language code along with many more details at:
http://www.thetemple.cc/story/halo.htm
