Being a technology geek since my childhood, and my general interest in all kinds of sex toys, it's easy to understand my fascination of electric/electronic sex toys. Obviously everything that somehow vibrates is already quite nice. E-Play, i.e. toys that apply electric current to the body (such as EMS/TENS units) also is of interest to me.
Please note that I'm not interested in using sex toys on myself. I like to use sex toys to play with a (my!) female toy. Yeah, men and their toys... they'll never grow up.
But what is probably the ultimate line of thought (and arousal) in this area are remotely controlled toys. There are butterflies/vibrating eggs with a cable 'remote' control, which is already quite nice. Being able to make "her" (the female toy) wear a butterfly under her skirt, hiding the cable under some clothes and putting the remote control into some belt bag or similar already poses nice opportunities, especially for provoking her physical sexual arousal in (semi-)public [but not too silent!] places.
Another interesting method is to attach any vibrating device (let's stay with the butterfly for some time, since from my experience this is the most effective, because clit-stimulating toy) to a computer. Now add a web cam or similar, and make your remote partner use that equipment. Software-controlled vibrators can also be programmed to perform very interesting "ramp-up the level slowly and then pause for some time" operations. I've built (and tested) one such device, and I can tell you it was incredibly joyful for both her and me. I didn't touch her once. She was tied to a chair, unable to close her legs or to touch herself with her hands. Wearing a butterfly connected to a computer, while I was controlling it from my laptop, carefully testing the various interval/pause ratio to see how she'll react.
Anyway, another project that I used to work on some three to four years ago, is a real remote control, by using tiny RF modules. There now are some cheap (well, actually they are only low-quality and still cost quite a bit of money) RF controlled sex toys, but they have extremely low range (3m), are unreliable, inflexible (just on/off) and low battery lifetime. Buying any of these is a terrible waste of money. So I was working on that DYI project. Unfortunately I then was with a partner who wasn't really interested in such forms of sex, and the project was abandoned.
I've recently been working on a number of RF communications related projects, including the design of a tiny, ultra-low-power 2.4GHz transceiver. The plan is now to reuse this design to revamp that remote control plan. Since the transceiver contains a small micro-controller, programming it with various vibration patterns/curves is not a problem at all, even on-the-air readjustment of the patterns is easy to do. A small control unit (key-chain-size) would probably only offer some three buttons (mode, up, down) to select pre-programmed patterns, but using a PC or some bigger PDA-like device you would have the full control.
Now stop the tech babble and get back to what I would do with that kind of device? Well, just get back to the start of this entry. I'm extremely fascinated by the possibility to "bother" my partner with physical arousal in unexpected situations. This device gives plenty of opportunity to do so.
The second version definitely also needs to include support for controlling some form of an electric shock unit (this could be a generic e-play output, allowing for soft stimulations up to hard shocks). Then the operator of the control unit is put into a position where he can both reward and punish at a fingertip. Yes, there are electric dog collars which basically support the punishment operation. But they look quite ugly, and are visible to the outsider. Also, I would want to apply the electric current at some different location ;)
Given my current spare time, it will still take some time to do this. It's not a skill level at all, mostly a time issue. But at the moment I'm aiming for August to finish at least the first vibration-only version.