This instructable shows you how to build a remote detonator that could be used for something like fireworks or rockets. The schematic is pretty basic and the parts are widely available so it should be easy to get them. The author states that the circuit has a range of about 90 m so that should cover a nice safe distance.
Radio Remote Detonator: [Link]
This project uses an ATmega16 and a radio control kit to get the job done. You can control up to four servo(motors) with a simple push of a button. The system can also control a servo with a photocell, for example if you enter its range it will turn on a light. Of-course there are a few commercial alternatives but the price is quite high and many of them are not a versatile as this one.
Garage Door Control System (or any device radio controll system): [Download Project] - [View Project PDF] - [Via]
Have you ever been into a boring elevator ? with no sound and level indicator lights ? because I’ve been and i can tell you its not a pleasant environment to be in. Those elevators are sometime rebuild or renewed but the level indicator lights and some kind of sound system are not installed because of the high price tag, and possible need of rewiring. This project comes with a solution, and an easy to implement one.
It features a voice message system which inform you about the current level and optional about the next level. It needs no connection to the elevators system, its powered by batteries so you just need to stick it somewhere inside the elevator. If i would to build this system i would also include an FM radio, because most modern elevators include this features and i think its neat.
Elevator Voice Message Level Indicator: [Download Project] - [View Project PDF] - [Via]