Before I start, here is the disclaimer. I bet there are going to be replies to this post warning about the dangers of homegrown PET devices. It is true that you should have an understanding of electronics before attempting to build your own but just because the idiot from around the corner may electrocute himself does not mean that a reasonable bright person can not construct their own device. That said, I have made my own device from old DC computer speakers. As I understand it, they are not as strong as some commercially made products but they work for me. The sensation depends on your use, you can make it painful or a pleasant tingling sensation. If I place one electrode in my butt and one on the tip of my penis, I can make it feel as if my penis is being sucked on ..... quite amazing ..... and the orgasm is very intense as well. I also like to place a single electrode, which I made from an old butt plug, into my ass and turn up the power .... let's call it a very strong tingling sensation The deciding factor of what you feel is the composition of the output. Most better commercial devices have an audio input jack. This allows you to connect a computer's sound card or a CD player to the device. The device will take the sound signal and adjust the voltage to a usable output level, keep it on a LOW setting until you know the sound file you use has no surprises. Compressiona artefacts like a clicking sound found in some low quality mp3 files can be quite painfull. I have found a lot of good information and audio files to play at the SmartStim Forum the wav files are produced using an audio editor such as Audacity but to try it out I suggest you check out the download section of the SmartStim forum first. The members on the forum post guides on how to make your own electrodes and PET devices, so instead of spending a lot of money on the expensive gear you can see if you like it before blowing your cash. Hope this helps, let me know if you have more questions.....