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Q. I was in the competition last year, and we were told never to exceed the 6.5 volts that the 4 AA batteries provided. Since this year we are using the same servos and circuit board, I assume the voltage requirements are the same. We are in the process of designing a chassis and need to know the proper power supply. I know the package says not to exceed this voltage but they gave us a 9 volt adapter.
A. The supply voltage needs to be 6V because that's the input requirement of the STAMP computer. I never found any documentation on the 9V adapter, but I believe that there is a step-down circuit on the board to drop the voltage from the 9V input. Since it's there, I'd guess it's safe to use the 9V battery if you'd like. However, you can provide much better longevity using AA or larger 1.5V batteries. You have the option of using Lithium AA's for example, which will last quite a bit longer than alkaline. You can also increase the battery type to a C or even D size safely (just get an appropriate 4 batter holder from Radio Shack) for longer run times.
If you are after a more juice (amps or volts or both) for motors and such, I'd isolate the motor circuit using a relay or optical isolator ( the STAMP computer turns on the relay with the 6V output which completes a circuit to the motor fed by a different battery pack.
If you are after more power out of the servos, consider switching to heavier servos from a hobby supplier and upgrading the battery size as mentioned above to avoid running your batteries down too fast.
We asked the Parallax people last year about using 9 volts. There is a voltage regulator on the BOE, so the stamp is okay with that voltage, but the servos that we had last year were only rated to 7.2 volts. They are not protected by the voltage regulator. That was why they gave a battery holder for 4 AA batteries. If you buy you own servos this year, and if they are rated for 9 volts you should be ok using a nine volt battery.
Q: Can I still participate in the 2003 competition?
A: No, the registration is closed.
Q: What are the events?
A: The novice events are:
The advanced events are:
Q: Will there be a technical assistance clinic?
A: Yes,
a technical assistance clinic is scheduled for Saturday, January 26th,
12:00 P.M. – 2:00 P.M., YSU.
Q: What happens if we lose or damage something from the robotics package?
A: You are responsible for ordering parts and/or documents from the vendor directly.
Q: Will we be getting any additional details about the events?
A: Your goal is to make the robot smart enough to go through any maze. I will give you a hint, the paths through the maze are 18 inches wide. If it becomes necessary to disclose more information we will do so at a later time.
Q: What is the design of novice maze one and advanced maze two?
A: The dead ends of the maze will be shorter than the desired path.
Q: What modifications can be made to the robot?
A: Any cosmetic changes are fine. You can make changes to existing equipment, however adding non-Boe Bot equipment is not allowed.
Q: Can you please elaborate more on the rule that "All electronic components must be used unmodified".
A: It means that the components that came along with the kit must be unmodified (if used), but additional components can be added. At minimum, the robot must use the power pack that was included in the kit, must use the unmodified servos included as its sole means of propulsion, and must use the included Stamp board as it's "brain". The total cost of added or replaced components must not exceed $100. The robot must not have any external controls of any sorts.
Q: Can we change batteries during the competition?
A: We strongly recommend changing batteries before each event including after any pre-or warm up runs on the day of the competition. The cost of batteries will not be included in the maximum spending limit of $100 for robots.
Q: Do we have to buy all electronic parts from Parallax?
A: No, however non-Parallax components may not work as well. We recommend purchasing Parallax parts.
Q: Can we add parts not in our kit?
A: No, you must use the parts included in the kit, however, you may purchase extra parts, i.e. sensors.
Q: How long is the Oral Presentation and do we have to use a display board?
A: The presentation is 5 minutes and no, you do not have to use a display board.
Q: What kind of lights will be used in the maze?
A: 20 watt halogen lights (the kind used for under cabinet lighting)
Q: I am having trouble figuring out how to get the robot to judge distances. When it gets to an intersection, how does it determine which direction to turn? The robotics book says that it can only go to about 25 centimeters (about 10 inches). I have read the section on frequency sweeps, but I am not comprehending it (at least the part of reading longer distances). Any help that either of you can give me would be GREATLY appreciated.
A: The main issue affecting the maximum IR distance sensing is the color of the reflecting surface (IR absorption). The second issue that affects distance is ambient light. The more light, the less distance. In our testing, we found that gloss white surfaces offered the best distance. We were able to achieve a maximum reliable distance of about 23 inches. we did quite a bit of frequency experimentation to get it there.
We recommend that you reproduce the conditions of the contest (corridor widths, opening widths, T's where the correct direction is always longer than the dead end direction, gloss white enamel maze walls, sodium vapor gym lights) in your testing, and you make your robot "smart" enough to deal with T situations where you "see" the wall in one direction, and where you don't "see" a wall in either direction and must further explore the hallway to determine the proper path.
Q: During the second advanced event, will we be penalized for hitting the wall?
A: Yes, there will be a penalty for hitting the wall in Event 2-Novice and Event 1 & 2-Advanced. The penalty is 10 points for each hit.
Q: We need the IR's to detect out to 24". I have tried frequency sweeps and am not having much luck. If I change the 220ohm resistor in the LED circuit, will that extend the distance, or will it smoke the LED?
A: I wouldn't go lower than the 220 ohm resistor, you might try using something that will magnify the LED, some sort of lens. I haven't heard of anything that increases the distance that far.
Q: The lights in the gym are not fluorescent, will that make a difference?
A: We have found by placing the IRs into a tube, the type of light was not the factor, it was the intensity.
Q: We have a competition event that requires the BoeBot to travel through the maze by following lights. Each light will come on in sequence. We are having troubled with the sensors detecting the light. We are using 20 watt halogen lights (under-the-counter types) are attached in the wall of the maze. The lighting condition for the event is a college gymnasium using vapor (whatever) lights. Can you recommend what we can do to make the sensors hone in the lights in the maze and not the overhead gym lights.