First thing -- it is simple "car" with two motors for movement, and we added it a sonar and a special key with color combinations matching secret gate code.
Gates: the bridge is connected by ropes, connected to motors on the top. Here under the EV3 Brick you can see our weights, we made them just for gates didn't fall. The most interesting is a color detector, in Mindstorms each color has its special color, we detect it from car's key, and even show it on brick, if it has correct combination gates will open by program! The gate just waits some time and then it closes the door. If the code is wrong, the gate will just not open and alarm sounds.
Color detector couldn't read some colours, so we were needed to re-choose a few times the code. We were doing it whole month, but actually it works! The code is quite simple. Just for the detection the robot moves slowly forward and program waits for each changed color in the key, but it has to be visible for a small time, because there was problem with false colors detected during transition. If the gate is open, the ultrasonic sensor will detect it and robot goes forward via the bridge. If the gate is not open, it moves back and tries again with the key.
The attached code file contains both programs for bridge and visitor plus an experiment (for checking the sensor problems during color transition).
Team: Lart (Kyiv), Dionis (Kyiv), Ondrej K. (Zilina, unfortunately not on the team picture as he was not present on the last club meeting)
1. Very nice design, I like the flexibility of entry codes, also how
everything works reliably. Excellent opening and closing mechanism. Just
a pity the gate does not close a little faster.
2. It is very nice, that you describe the solution of the assignment in the video. I think that it will be more perfect if the time of moving up the gate will be a little bit shorter. :)
3. Hello Lart and Dionis and welcome onboard the Robot League! We are happy you have joined the program and the legendary Benders team. I enjoy your satisfaction from solving the challenge. That's the right attitude! The solution is complete. I would appreciate if the robot would take some action in front of the brigde instead of just letting to be observed. The task specification says: "...will announce somehow that it wants to enter", which indicates an active involvement in the process. We hope you get some more inspiration by looking at the solutions of other teams. We look forward to your next round! Good luck.
4. Great job guys. Nice explanation. You have completed the task. Maybe next time you can show more good attempts to make sure it wasn't a coincidence.