This is a fully automated model of a Hungarian-built bus.
About this creation
This model represents my first large-scale Mindstorms project. The aim was to build a model of a bus that would look like the real thing and incorporate some interesting robotic capabilities. Here are some of the characteristics of the bus:
The bus is able to follow a route based on some hardcoded legend (i.e. solid black line means go and a solid red line means to stop and pick up passengers). For that purpose I used two light-detectors. (one for each side of the line)
The doors are pneumatically-operated. For that purpose I incorporated a motor to serve as a compressor and a mini-motor to switch the direction of air flow (doors open/close).
The bus incorporates 2 rcx microcomputers, one to process the input from the light sensors and control the movement of the bus (i.e. driving and turning) and another to open and close the doors by controlling the compressor and the direction of the airflow. Thus the second rcx is a slave - it waits for a command to open doors from the first one.
Here are some of the problems with the bus that need to be corrected:
I have underestimated the final weight of the model, and so the rear-wheel drive bus propelled by two motors is seriously underpowered. As a result the bus travels at a snail's pace at best, and at worst (like if there is an obstacle in the front) the torque built up from rotating motors rips the motors out of the under-body of the bus.
The turning radius of the bus is huge. This seriously puts the design of the route in jeopardy, since incorporating any significant turns is a challenge.
And finally I encountered a perennial problem with Lego designers - I ran out of pieces, which is especially evident if you look carefully at the roof of the bus.
A final note about the model. Ikarus buses were, and still are, very popular in Eastern Europe. I have used them a great deal when I was growing up in Russia, so it made sense to build a model of a bus which roughly resembles an Ikarus.
The front under-side of the bus. On the left is a compressor with the pneumatic switch controlled by a mini-motor. On the right are the two light sensors to keep the bus on route. An in between is the motor controlling the turning of the front wheels.
great bus, but why did you use 2 RCX instead of one? You could make it with only three motors: 1 driving, 1 steering and 1 for the compressor with an autovalve (like this one I build for my supercar) and 3 sensors: 2 light for line following and 1 touch for center the steering.