The Eggfinder - A Low-Cost GPS/RF Tracking System

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cerving

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As many of you that have purchased Eggtimer altimeter kits know, I have developed a simple GPS/RF tracking system. It's called the Eggfinder, there's a transmitter that goes in your rocket and a receiver that stays on the ground. Basically, it streams NMEA 0183 serial GPS data to your ground device (laptop, tablet, possibly Android smartphone), and can be used to track your rocket in flight and more importantly to tell you where it went so you can get it back. You can use just about any mapping software with it that can take NMEA GPS data input; the only restrictions are what your device will handle.

The transmitter runs on the license-free 900 MHz band, the module that I use (the Hope RF HM-TRP) is the same one that's used in the popular 3DR radios. The firmware in the radio modules is Hope RF's standard firmware; this is to ensure that the radio complies with the FCC's spectrum requirements as tested by Hope RF.

Details are at https://www.eggtimerrocketry.com/page21.php , cost for the kit will be under $100. Availability should be sometime this Spring; I'm finishing up the documentation and waiting for parts.

Cris Erving
Eggtimer Rocketry
 
Very interesting and looks perfect for my Speedy Gonzales rocket. Best part is the low cost :D


Alexander Solis
 
I want one.

Maybe two.

I hope you'll sell them separately so you can have two transmitters and one receiver.
 
Ok, you posted this today, does this mean it is springtime and they are on sale:)
 
You have my attention!

The size and price are looking very attractive right now.

Alex
 
Yes, you will be able to buy a transmitter separately. Most of us have lots more rockets than laptops, tablets, and/or phones... unless you have teenagers.

I want one.

Maybe two.

I hope you'll sell them separately so you can have two transmitters and one receiver.
 
What would be REAL nice is an ability to have two trackers transmitting at the same time and the receiver picks up both signals. Particularly useful for two stage, etc, designs that may need tracking on both stages.
Being able to plug a mini usb cable directly from the receiver unit into an Android device (phone / tablet) would be great, even if all it does on that platform is display the current GPS co-ords!

Yes, you will be able to buy a transmitter separately. Most of us have lots more rockets than laptops, tablets, and/or phones... unless you have teenagers.
 
They will be available in several different 900 MHz band frequencies (I'm choosing them so they are regulatory compliant in the US, Canada, and Australia) so you can fly more than one, or several people can be flying them simultaneously. If your device can handle more than one serial port, I don't see why you couldn't track two simultaneosly; I'll have to try it when I get a chance. My gut feeling is that Windows can handle it and Android might be able to handle it using Bluetooth(R).
 
I just got one Eggtimer assembled yesterday. Will probably do the next one this weekend. More features on that than I can shake a stick at, THEREFORE I will surely want an Eggfinder!
-Ken
 
Looks like I'll be buying several when they become available as well.

David
 
Unfortunately, I won't be shipping outside the US initially. I need to get a grasp on the Canadian and Australian regulations first. There are a few hurdles, particularly in Australia.
 
:DYou have just given me a good idea. Why not scent the parachute,then use a tracker dog to find it, any old Beagle will do. Might even get one for free at the pound.:D
 
Here's one, the transmitter is mounted in a sled that wedges into the nose cone of my Giant Leap Escape Velocity, I zip tie it to the screw eye for good measure. I just double-sticky tape the receiver to the back of my laptop LCD... I'll put it in a project box one of the se days.

This is with the stick antenna option, you can optionally solder a RP-SMA connector in its place for an external antenna.

EV Eggfinder Nose Sled 001.jpg


Take me down for one, any pictures of the setup?
 
Very cool I want to test one out at thunder struck in april .
 
At this price I can afford to buy 6 of them which I will need in my next rocket, Have you ruled out on shipping to all internationals?
 
Too soon to say. I know NZ's spectrum regulations are similar to Australia's, some frequencies in the 900 MHz band are license-free. It's the certification/kit issue that I don't know about... it's VERY difficult to find information about it one way or another. You can't believe stuff you see on the Internet about these issues, you have to get it from the regulatory bodies themselves, preferably in writing.

At this price I can afford to buy 6 of them which I will need in my next rocket, Have you ruled out on shipping to all internationals?
 
Have you flown the GPS module you're planning to use? I see on your web site that you want to use a SIRFstarIV-based system. Older SIRF units are notoriously bad for not working in rockets. Just FYI.
 
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