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want to make a bs2 controlled hovercraft — Parallax Forums

want to make a bs2 controlled hovercraft

rockybulwinklerockybulwinkle Posts: 36
edited 2005-09-16 13:48 in Robotics
want to make a bs2 controlled hovercraft that will navigate to a destination using a gps, which is the garmin etrex vista,· and the ping ultrasonic range finder.·The problem is that I have the usb version of the boe, and the gps, and the cable output uses a db9. my dad won't buy the adapter even though I would pay for it, and I'm not even sure he will let me use his gps. He said that there is probably a gps computer chip I could buy. I found the vs7001, but couldn't find any where to buy it and am not sure if it is even out of development yet. any help with this would really be appreciated.

Post Edited By Moderator (Chris Savage (Parallax)) : 9/7/2005 11:58:36 PM GMT

Comments

  • rockybulwinklerockybulwinkle Posts: 36
    edited 2005-09-08 00:12
    actually I think that most of my problem was in how I thought that the cable had to connect to the usb. I just now looked at the serin and serout and it looks like it uses IO pins rather than the usb. if I'm right, could somebody suggest a method to attach it to the bs2 without damaging the cable? Would I have to buy a db9 socket?
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2005-09-09 16:35
    Buying a DB9 socket would get you started. If you want full RS-232, you have to either use a MAX232 chip to convert the BS2 pins or build another kind of rs232 interface. Two things happen in the conversion - the data is inverted and the swings from the BS2 at 0 to +5 volts are converted from +12v to -12v [noparse][[/noparse]often less, but it works with a negative voltage that you must have]

    If you just want the BS2 to recieve data, it gets much easier. It happens to block the negative voltage and with a simple resistor you can get the RS232 received. The BS2 can accept inverted data. Read the proraming manual to understand how.

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  • rockybulwinklerockybulwinkle Posts: 36
    edited 2005-09-10 19:36
    ok, that makes Much simpler and cheaper. I just need to get information on the location. I've bought the hovercraft, it should come next week or the week after that.

    Do you think that my bs2 will have enough EEPROM to both the code and locations of objects that it has detected, or will I have to buy a bs2sx or pe? I want to store objects because then it can build up a "mental" map, really in a similair way bats and dolphins do.

    I wanted a hovercraft because they can go over ice, pavement, water, and maybe, though i'm not sure, grass and carpet. that would mean I wouldn't ·have to keep a very close eye on it.

    Is there a way to make it know if it is going to be able to cross a large bodies of water like small lakes and oceans? would it be feasable to have it recharge while running on several solar panels?
  • rockybulwinklerockybulwinkle Posts: 36
    edited 2005-09-10 19:47
    I forgot something. I have heard of solar cells that utilize infrared light and visible light in a science news magazine. If anyone knows if there a sources for these at a low price, you tell me?
  • rockybulwinklerockybulwinkle Posts: 36
    edited 2005-09-13 01:29
    Its starting to feel like i'm just talking to myself online. oh well. anyways, do all of you people think·about connecting the motors to the bs2 by connecting·a pin on the basic stamp to a diode, which would only let electricity out, and after that have a junction with a resistor and one terminal of the motor, with the resistor going to ground. if I were to use two of these for each motor, could I control the motors sufficiently?

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  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2005-09-13 01:37
    Hello,

    ·· You would burn the pins out on the BASIC Stamp doing that.· Besides the possibility of drawing too much current, you would also cause sudden voltage drops when the motors started.· It's never a good idea to connect a load device, such as a motor directly to the BASIC Stamp I/O pins.

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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • allanlane5allanlane5 Posts: 3,815
    edited 2005-09-13 13:31
    Mr. knex_master:

    The reason you feel like you're talking to yourself is that you are trying to do something very ambitious, and you don't seem to be paying attention to our feedback.

    Also, you seem to be limited in funds, which makes it unlikely you'll be able to finish your ambitious project. Also, when people say you'll need to buy something more to do the interfacing you want to do, you argue with that.

    It would be much better if you would divide your project up into parts, get each part working, and then integrate those parts together.

    Also, a hovercraft flying in the air may not be able to use the 'ping' sensor. As I understand it, the 'ping' sensor is limited in distance to like 2 feet, and it kind of assumes it's on a robot on the ground. It can tell the robot when there's something in front of it.

    Also, a hovercraft toy probably doesn't have the cargo carrying capacity to carry a BS2, GPS, and ping sensor.

    However, if you succeed it will be really impressive. I'm sorry we haven't been posting back to you all this time.
  • rockybulwinklerockybulwinkle Posts: 36
    edited 2005-09-15 21:12
    I guess I was starting to get carried away, especailly with the solar panels.what if I used a transistor instead? if I were to have the collector connected to +9.6v, the base go to the basic stamp, and the emitter go to the motor, would it be safer for my bs2?

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    There are 10 kinds of people in the world;

    those who understand binary and those who don't.
  • rockybulwinklerockybulwinkle Posts: 36
    edited 2005-09-15 21:34
    I'll test the hovercraft to see if can carry the loads' weight at in about 2 hours, when the batteries will be full.

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    There are 10 kinds of people in the world;

    those who understand binary and those who don't.
  • allanlane5allanlane5 Posts: 3,815
    edited 2005-09-16 13:48
    I think you need to download some of the Nuts&Volts PDF's that are on the Parallax website -- specifically the one for motor control. That will give you the circuit you need to put between the Hovercraft motor and the BS2.

    Then -- you must realize, a solar-cell puts out very little current or voltage, for a long period of time. The power it puts out, while low, is free. But I don't think you're going to be able to charge a 9.6 volt battery at the same time the battery is holding a hovercraft in the air.

    One possibility is to fly the hovercraft for 15 minutes or so, then land it and charge for 8 hours or so -- but even then that might not be enough.

    A suggestion: Focus on getting the hovercraft working under BS2 control -- have it fly in a small square pattern, for instance. Then encorporate the 'ping' sensor, and try to get it to avoid objects.

    Do write down all these ideas you are having -- they're pretty cool, even if they don't work yet. But you need to focus on nailing down one or two, before you start speculating about the rest.
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