To assemble the apparatus for electrical stimulation just
1. Buy any speakers (1-3 W)
In one of the speakers is a bass amplifier with a step-down transformer on the input transformer of the cut, instead of connected stable power supply 9-12 V
Cut the wire from the second column and plug instead (the second speaker) transformer (nizkovoltnoy party (5-6 In) to the input 220 to the output (ie, the electrodes)
electrodes purchased in any equipment (
http://www.velord.ru/)
The transformer is needed as far as I understand for impedance matching of the object of stimulation and the stimulator
You can disconnect the second column, that would be during work, not cracked
2. download online any program - signal generator (here
http://gvallos.narod.ru/gs.htm either
http://genealogic.narod.ru/audio/generator.htm) , or in the audio editor, draw the signal (and stored in WAV!!!), the frequency of the pulses of 20-30 Hz (for transcranial electrostimulation of 77.5 Hz)
A sound card usually has a passive input filter to suppress frequencies below 20-40 Hz, but the filters are not perfect, so in any case, you can get a signal from 1 Hz, albeit not a perfect step, but for sleep is enough (skin is known, too, distorts, so striving for perfection is silly), you can instead ipulse current use triangular - is softer, the effect is the same (the effect is not the pulse shape and the number of the transmitted energy, a rectangular he's the best)
3. read about the electric in the old textbooks on physiotherapy