This page describes how to make a vibrating "egg" that can be switched on or off by using an ordinary pocket pager. You must have pager service, of course. Someone dialling the phone number or the pocket pager can trigger the vibrating egg for a few seconds.
(Note: This project is not for the electronically timid. It assumes that you know how to solder and how to identify electronic components, and that you are good at working in tight quarters.)
Building a sex toy controlled by a pocket pager isn't terribly difficult. What you'll need are the pager itself, a sex toy of some sort (it's by far easiest to work with the kind that has a battery pack connected by a wire to the toy; I usually use the "vibrating egg" variety of toy), some fine wire (I use Kynar wire, usually used for wire-wrapping; you can get spools of it at Radio Shack), and a relay or a "solid state relay." The relay is necessary because the pager operates on a different voltage from the sex toy. You will need either a small 1.5 volt reed relay (probably won't find this at Radio Shack; they sell 5 and 12 volt relays) or what Radio Shack calls a "solid state relay" (which is manufactured by Sharp Electronics, part #S101S05V; Radio Shack's part # is 275-310).
STEP 1: Modify the pager
The hardest part of the project is usually opening the back of the pager. I use Motorola pagers; the Motorola alphanumeric pagers are easiest to work on but expensive; the cheap Lifestyle and Bravo pagers are much more difficult to modify. These things always snap apart in some way, although it's usually tricky figuring out how. Alpha pagers, for example, have a long, thin rectangular section on one side; you pry up one end of this part with a fingernail, slide the little plastic rectangle out, and then pry the shell open.
Once you have the damn thing open, look for the little motor that controls the "vibration" setting. On alpha pagers, it's in the half of the shell away from the electronics. In Lifestyle pagers, it's in the center of the pager, sandwiched between two circuit boards; you need to gently pry the two circuit boards apart (they are connected by a pull-apart connector). On cheap pagers sometimes sold in places like Radio Shack, the motor is in a clamp soldered to the circuit board; you'll have to carefully heat the solder joints while you pry on the clamp with a jeweler's screwdriver.
Once you've found the motor, pry it out of its housing. It will probably be held in with a clamp; in alpha pagers, it's just sitting in the plastic shell of the pager. Find where it gets its power from--in an alpha pager, there are two wires that lead to springs, and the springs touch two spots on the circuit board; on a Lifestyle pager, there are two metal studs on the sides of the motor, and these studs touch two small brass "fingers" on the clamp that holds the motor. What you'll want to do is solder a short (3" or so) piece of Kynar wire to each one of the spots on the circuit board where the motor would normally get its power. If you want to test that you have the wires attached right, set the pager to its vibrate mode and send it a page. If you have a volt meter attached to those two wires, the needle will move when the pager receives its page.
STEP 2: Modify the vibrator
Now it gets easier. If you are using a reed relay, attach one wire to each "coil" connector on the relay. If you're using a solid state relay, there are four leads on it: two labeled "~", one labeled "+", and one labeled "-". The wires go to the "+" and "-" leads. You'll need to make sure the "+" motor connection goes to the "+" lead and vice versa; you can either experiment or use a meter to figure out which wire is + and which is -.
If you're using a reed relay and a large pager, you might be able to fit the relay into the case where the motor used to be. Otherwise, you'll need to find somewhere else to put the relay or solid state relay. One possibility is to attach the wires coming out of the pager to a jack, put the relay in the toy's battery pack, and run wires from it to the other part of the jack. Another possibility is to Epoxy it to the back of the pager shell. Either way, put the pager back together.
You'll need to open up the battery pack of the toy. If you managed to get the pager open, this will be a cakewalk. If you examine the battery pack and the vibrating egg, you should see 2 wires that lead from the egg to the battery pack. One of these wires goes directly to a battery contact in the battery pack; the other wire goes to the speed control dial, which then in turn goes to the other battery contact.
What you need to do is cut that wire, and cut the wire that leads from the other contact on the battery pack. So you should have one wire that is attached to the second contact on the battery pack, and another wire which leads out to the egg.
You'll have the right wires if you can touch the stripped ends of the wires together and make the egg vibrate.
Assuming you have the right wires, these are the wires that go to the relay. Essentially, the relay is taking the place of the little speed control wheel in the battery pack; the speed control wheel should be completely bypassed.
Now you're going to take these two pieces of wire and run them to the relay you have connected to the pager. If you're using a reed relay, they go to the two "switch" or "load" leads on the relay. If you're using a solid-state relay, they go to the two leads marked "~".
Put the battery pack together and that's it! You will need batteries in the toy AND in the pager for this to operate; the pager's batteries, by themselves, are not powerful enough to run the vibrator. Now whenever the pager is set to its vibrate mode, the pager will activate the relay, which will in turn activate the toy, when it receives a page. Enjoy!