Orlando Mihich, Facilitator

Patrick Mahaney, Mentor

Arkadiy Kukarkin, Constructor and Programmer

The RoboEye

by Patrick Mahaney

Ever since the first legos rolled off the production line, they have been captivating audiences of all ages. The latest product to roll out of the lego factory is known as the RCX. To others, it is known as the brick.

The RCX is a completely autonomous microcomputer carefully engineered into something that resembles a large lego block. The RCX is capable of operating three output ports individually, or simultaneously, which may control lights, motors, or sound elements. As well as output ports, it also has three input ports, which may be connected to temperature, light, angle, and touch sensors.

The RCX receives the list of instructions to be carried out from a host computer via infrared communications. Once the program is received, the only thing the user must do is hit the green "run" button. From there, the RCX goes autonomous. Depending on the complexity of your program, no user intervention is required.

The Roboeye project is an example of one of the more advanced things that can be done using the RCX. In this project, it has been given a sort of "intelligence" to be able to react to objects around it.

The RoboEye resembles a combination of a Tank and an Insect. The tank treads give it a lot of power to carry a heavy load on varying terrain, while the insect like antennae relay information to the RCX about its surroundings.

This Roboeye has two touch sensors and one light sensor. The program has been adapted to utilize all three of these sensors to give it a certain "intelligence." The touch sensors are connected to long antennae which determine whether or not the RoboEye has run into an obstacle. When this happens, the programming tells it to back up and turn in the opposite direction of the side that contacts an object. The same is true for the other side. This allows for the RoboEye to navigate around objects.

The third light sensor is also used for navigation. Its function is actually personal safety. It rides low to the ground on the front of the RoboEye, and scans for a light intensity drop. For example, when it is traveling across a light colored table, conditions are normal and everything is safe. However, if it should happen to venture off the edge of a table, the light sensor will detect a sudden light intensity drop, and the RCX will run a program to turn around and continue on, thus avoiding near certain death, and several dismayed programmers.

To complete the project, a wireless video camera has been added to the top to provide visual information to any human observer. This comes in handy if for some reason it ventures out of sight. It also just looks cool. The camera transmits on the 2.4 GHz frequency. Not only does it broadcast video images, it will also broadcast audio. So, the RoboEye can be used for covert spy missions as well. If it doesn't do what you want it to, simply re-program it to suit your needs. It's that easy!

So, whether you want to have something to entertain your pets, scare your neighbors, spy on your co-workers, search for dust bunnies behind the couch, or just want something that looks cool that you can show off to your friends, the RoboEye is for you!

by Arkadiy Kukarkin

Introduction. The RoboEye is a self-navigating vehicle that uses a number of sensors to find its path through the environment. A number of extra features were added. A hull-mounted wireless video camera which transfers signals (pictures) to a receiver is a useful addition in some real situations, such as exploring of non-human friendly regions. Two long sensory antennae detect obstructions, and a light sensor scans for terrain plunges.

Construction. The model is built mostly of Lego elements. The main parts are: two touch sensors, one light sensor, RCX 1.5 microcomputer, and the wireless camera. The chassis consists of two tracks driven independently by two motors. The camera is removable.

Logic. The navigation is based on the contact method: whenever one of the touch sensors mounted in the front touches an object, it sends a signal to the central computer. When the computer gets this signal on one of the incoming data ports, it turns both motors in a backward motion for 5 seconds, and then reverses the respective motor, thereby turning the RoboEye in the opposite direction to the obstacle. After this procedure is completed the normal movement continues. Another problem such a vehicle can face is running off a surface edge resulting in equipment damage. To prevent this, we used a distance sensor. The two parts of it are the light source and the light sensor. During the procedure of distance measurement the source emits light, and the sensor receives it reflected from the surface. The further away the object is, the more light gets diffused, and the sensor receives less light. This is also affected by overall illumination, object color, etc, so it cannot be used for accurate measurements. However, when the RoboEye with this system mounted on it reaches the edge of the table, it detects that the light level is much lower and, therefore, the distance to the surface is greater. The central computer analyzes this information and launches a backing-up program.

Programming. Lego ROBOLAB interface was used. The process of programming is represented by connecting logical modules and modifiers: each element (or group of elements) is an action, a trigger for another action or a condition. This interface offers less freedom than the traditional programming, but allows one to create programs faster and make them easier to manipulate. The completed program is transferred to the microcomputer via the infrared port.