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GPS Rocket Locator — Parallax Forums

GPS Rocket Locator

Alex HunterAlex Hunter Posts: 18
edited 2006-11-14 14:53 in Robotics
I have learned so much by reading these forums I figured that it is time for me to contribute. So many people have questions about GPS, so I hope this will be of assistance. I have attached pictures of the GPS rocket locator that I built a few months ago for my first basic stamp project.

PHOTO GALLERY

The GPS locator allows me to remotely view the coordinates of my rockets. The locator displays the current coordinates and can also store the last minute of data. This is useful for when the rocket lands and the radio connection is lost, but the last data points received can be viewed and plugged into my Garmin extrex.

Two components of the system fly in the rocket: the GPS receiver and the radio transmitter. This transmitter sends the serial data from the GPS to a receiver on the ground which is connected to the BS2. The BS2 parses the data and displays the current coordinates on a Scott Edwards LCD display. The three pushbuttons below the display are used to control the recoding function and to view the saved data.

I used two aerocomm AC4490 (www.aerocomm.com) transceivers to send the data from the rocket to the ground. These radios have a range of up to 4 miles line of sight and are meant for transmitting serial data. Also, they are small and lightweight, and cost much less that comparable radios. Configuring them was a bit of a challenge. I ended using the stamp to send the TTL level serial programming strings to the radios.

The GPS receiver I used was Garmin GPS 15 OEM module. I chose this because it was the cheapest and smallest I could find, but now I wish I had bought a WAAS capable receiver for the greater accuracy.

I have attached the BS2 program. I am sure there is much room for improvement in the coding.

So, I hope this will help someone get started with a GPS project. I would love to hear what people think. If anyone would like any more details, feel free to ask.

-Alex Hunter

Post Edited (Alex Hunter) : 4/13/2005 3:34:41 AM GMT

Comments

  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2005-04-13 05:02
    Alex,

    · Very nice!· Very ambitious project!· Wouldn't mind seeing a picture of the rocket setup ready to fly too!· All you need now is a Stamp-controlled launchpad countdown/ignition system!· LOL



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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • JonbJonb Posts: 146
    edited 2005-04-13 11:16
    Quite an advancement compared to the methods we used years ago to locate our lost hobby rockets... grid searches.lol.gif

    I also remember using a "spark gap transmitter"·and a·directional antenna with very little success. You must be using quite a large rocket to lift such a load. What is the total weight?

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    Post Edited (Jonb) : 4/13/2005 11:41:21 AM GMT
  • bishopbishop Posts: 82
    edited 2005-04-13 13:19
    yeah...lets see some rockets
    [noparse]:)[/noparse]

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    **************

    daniel woolston
    Teksystems Inc.
    www.danwoolston.com
    **************
  • Ray IddingsRay Iddings Posts: 47
    edited 2005-04-13 15:27
    I hate that you guys are soooo smart! smile.gif

    Lets see some Rockets!


    Ray

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  • Alex HunterAlex Hunter Posts: 18
    edited 2005-04-13 17:10
    OK, here are a few of my rocket pictures:

    PHOTO GALLERY

    there is also a picture of the GPS locator being insterted in a 2.1" nosecone. The long blac wire is part of the GPS antenna. This is the smallest nose cone that it will fit in. That nose cone belongs to a rocket that is 32" long and weighs about a pound. For comparison, the yellow and black V2 in the pictures is 5.5" in diameter and weighs about 5 pounds. The white rocket is 2.5 inches in diameter and in that picture it is on its way to over 5K feet.

    Now, I just scratch the surface in the high power rocketry hobby. If you want to see some really big rockets, go here:
    www.jcrocket.com
    click on fleet and search in the M-O motor class.

    I think this 2-stage rocket went over 40,000 feet:
    www.jcrocket.com/nike-asp.shtml
  • Ray IddingsRay Iddings Posts: 47
    edited 2005-04-14 22:05
    wow!!

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  • bishopbishop Posts: 82
    edited 2005-04-15 14:44
    cool rockets.
    i didnt realize that there was such a large community for that kind of thing.
    my wife said no to the rockets tho.· [noparse]:)[/noparse]
    apparantly robots cost too much as it is.

    is it me, or does the guy in picture0090.jpg look like wil wheaton from star trek?


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    **************

    daniel woolston
    Teksystems Inc.
    www.danwoolston.com
    **************
  • bishopbishop Posts: 82
    edited 2005-04-15 14:53
    see attached picture for the unbelievers:

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    **************

    daniel woolston
    Teksystems Inc.
    www.danwoolston.com
    **************
    309 x 383 - 28K
  • NoodlesNoodles Posts: 19
    edited 2005-04-25 21:17
    Hi Alex,

    I appears I am working on the counter-part of your rocket. I am making a bs2p rocket launcher, however this is a bit small for your rockets. Basicly it consists of an old hayes smart modem 1200 ( just the extruded case) and a s3 tilt/pan kit from crustcrawler. i plan on launching size A rockets from it and am working on useing some kind of range detection. The idea is to link distances to the angle that it was taken from, then constantly compare them to the inital reading...if there are any changes it'll examine them closer then launch... perhape we can share notes...stand by for photos
  • SofalogicSofalogic Posts: 49
    edited 2005-04-27 02:14
    Is it me, or does Ray Iddings look like Kurt Vonnegut? I showed the cooll rocket stuff to some of my students. The group is either currently studying microcontrollers or soon will be. The next batch may do some rocketry for the class project. There is nothing like using fire to lob something into the air. I like the idea of the tilt launcher. Using some good ballistics you should know where the rocket should land. Then fire for effect.

    sofa
  • ToadToad Posts: 5
    edited 2005-06-22 17:02
    I am currently tryin' to interface the compass appmod with the Boe and trying to get info on how to output the results to a analog input on my Rdas altimeter...cant seem to get it??!!!!



    the rdas has telemetry to my laptop..I'd like to ck for spin on my rocket...any ideas guys????
  • Alex HunterAlex Hunter Posts: 18
    edited 2005-06-23 01:34
    Have you seen this? www.aeroconsystems.com/electronics/rdas-magneto.htm

    assuming that you want to build your own, the compass appmod might not be the best choice for a rocket. From the dismore instruments website:

    "The 1490 sensor is internally designed to respond to directional change similar to a liquid filled compass. It will return to the indicated direction from a 90 degree displacement in approximately 2.5 seconds with no overswing."

    unless i am misunderstanding this statement, it sounds like it would not respond fast enough to measure high-speed spinning. I don't have any good ideas for ways to measure this spinning, maybe someone else has some good advice.
  • ToadToad Posts: 5
    edited 2005-06-23 02:08
    thankx for the info I didnt see it....

    I also am having a problem with the rdas not responding since I upgraded my usb port on xp..



    my printer works ok but not my usb to serial port cable..any ideas???

    I've tried several attemps to correct it by tryin' the microsoft way..

    humm??

    still would like to know how I can read the output of the Boe board to use the rdas ...

    how do I get the data to the inputs on it??

    tkx
  • laozeilaozei Posts: 3
    edited 2005-07-23 08:29
    Hi Alex Hunter:
    I have the problem with AC5124(aerocomm).
    I use the UART(Universal Asynchronous Receiver/Transmitters) to receive the data from the AC5124.but the data not very nicety. Can you tell me the how to receive the data ? or which signal can tell me the data will come?

    E_mail:honghuanatG4@hotmail.com
  • Alex HunterAlex Hunter Posts: 18
    edited 2005-07-25 03:58
    hmm... more information would be useful. If I understand you correctly, you have two of the radios and you are trying to transmit data between them, and the data being output from the reciever is not what you expect? Pin 14 is the data out pin on the AC5124. Were you able to properly configure the radios? There is lots of information in the user manual, try looking it over again. I'll try to help you if I can, please post more details.
  • laozeilaozei Posts: 3
    edited 2005-07-29 04:39
    I can configure the radios properly.
    The reciever have recieved the data,and will send to my UART,
    but I don't know when the data is output to my UART. I used rx data ready interrupt to recive data . but a few data of the start of a frame are missed .
    CTS
    >RTS
    mx1 RTS
    >CTS ac5124
    Will the RTS can control the data out from the AC5124 (when I want the AC5124 output the data,I pull down the RTS)?
  • laozeilaozei Posts: 3
    edited 2005-07-29 04:53
    A frame has 1000 Bytes.The UART Rx FIFO set 32byte. when the FIFO is full ,an interrupt will occur.And I use DMA to read the data.
    but I don't know whether the first data in recived data are the start of the frame.!
  • damiondamion Posts: 39
    edited 2006-03-28 21:44
    Hello Alex,
    cool project, I'm tring make something similar. I'm still pretty new at this whole electronics thing but I'm trying to build a sensor package that gets launched in a rocket takes readings and transmits the info back to a ground station. I'm using the bs2p with the aerocomm 4790-1000 I'm realling confused as to whats required as far as hardware and software are concerned. If you have a shematic for your project it would be very helpful, also any advice would be appreciated thanks.
  • RinksCustomsRinksCustoms Posts: 531
    edited 2006-06-29 06:03
    hi all,

    just a quick snip on measuring the spin rate on the rockets. If it's possible, you could take the nose cone, mount it on an axle supported by ball bearings, attach some vert fins that will stablize the cone and put a magnet in the cone and the hall sensor on the body side, then you could measure rpm, calculate rotational acceleration.

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    Definetly a E3 (Electronics Engineer Extrodinare!)
    "I laugh in the face of imposible,... not because i know it all, ... but because I don't know well enough!"
  • daveedavee Posts: 35
    edited 2006-10-11 04:50
    And if you're a HAM, you can buy a MIM module and wire it up to just about any VHF transciever and use APRS to track it. Since APRS can be accessed via the internet, as lomng as there is a HAM radio operator running APRS with ten miles of the launch site, which there probably is, unless you're inthe middle of the desert, in which case, forty or fifty miles will do until it the rocket gets below a hundred feet or so. You have to be a ham though.

    You can get around this by hooking up a GPS to a cell phone and have the cell phone make a call at about five hundred feet or so. If you have free minutes, it only costs the cost of a cheapo cell phone. Weight is less than an ounch more than the weight of the cell phone and GPS reciever, basically a gps, a nine volt battery, a 7805 regulator, a dip chi and a cell phone, along with cabling.

    APRS is a gps tracking system using VHF radio, created by Bob Bruninga in the late 80's andpopulariezed in 1992, which is when I first strated using it.

    MIM modules are a single board about twice the size of a postage stamp that includes everything you need to connect GPS receivers to VHF radios and make APRS transponders, very popular with the balloon crowd. Lot's of us put them in our cars, bicycles, boats, everything that moves. We can watch our loved ones using the APRS vhf network or since the APRS network is connected to the internet, watch it from any browser in the world, more or less.

    Google APRS. The cell phone variant is just as easy to build and less expensive, since almost all cell phones are smaller than most vhf radios and require no radio license to tinker with.

    Dave (N6TAU)

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    Dave Evartt

    FUSION robotics
    What's in YOUR robot?
    http://wehali.com
  • AImanAIman Posts: 531
    edited 2006-11-14 14:53
    Just a quick FYI

    I was looking at using the Garmin 18 for the DARPA challenge. Its about the same size as the 15 and in my mind is the better of the two. Cost wise its still comparable to the 15.
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