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

[Wayco]

I got two more flights with Eggfinders Saturday at ROCstock, both worked flawlessly. First flight was in my 5" Jart "Jughead". Flew on an AT L900 Dark Matter to 9330 ft. Eggfinder tracked throughout the flight. With "Rocket Locator" on my Android, it was a breeze driving out over the playa right to my rocket. This stuff could spoil you.
The second flight was with my 3" Blackstar on a K513 Fast Jack. I rebuilt the N/C similar to the Jart so I could use the same sled in either rocket.
Much higher acceleration finally caused the Eggfinder to break lock, but picked it right back up at apogee. Same results, drove right to the rocket. I don't think I could have flown four dual deploy high power rockets in one day without the Eggfinder. I still had the energy to fly Warp Core Breach that night. It was a much harder recovery, the winds were moving right along at 9 pm. I didn't feel driving my Jeep around in the dark with all the kids running around was safe, so I chased WCB almost to the highway on foot. Fortunately, it was too heavy to get drug, just laid there waiting for me to turn the lights off. Long walk back with an 8 lb. rocket.
After Jugheads flight, I went out and recovered Cris, who was way out on the playa recovering his rocket. He showed me the new RX unit with the LCD screen, pretty slick unit with GPS coordinates right on the screen, and you can change the frequency it works on with an internal switch. So I bought Sharon her own Eggfinder on 921 Mhz. so we can fly our rockets together, and use one RX unit to find them with.
Cris was a little nervous cruising back to the launch area, I don't think he has been in a Jeep at speed before, even though I did slow down a little for the ditches....:grin:

 

[KenRico]

I saw these in action ..and met Cris also. Placed an order this afternoon for the set and a pair of the Finders also.

Wish me luck..will probably ask for help with the soldering.

Kenny

 

[chuck5395]

After Jugheads flight, I went out and recovered Cris, who was way out on the playa recovering his rocket. He showed me the new RX unit with the LCD screen, pretty slick unit with GPS coordinates right on the screen, and you can change the frequency it works on with an internal switch.
:grin:

Rut Roh! I sense that this is yet another device from Cris that I must have.....

 

[soopirV]

Rut Roh! I sense that this is yet another device from Cris that I must have.....

Ditto That!! What's the haps, Cris? Is there something new on the horizon or were you just showing off?

 

[Ringo]

Do you know when the new receiver with LCD screen will be released?


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[Area66]

Do you plan to eliminate the annoying button we have to press and wait for green light, or is there a mod to bypass it ? A on/off switch that we can arm when the bay is closed will be less annoying.

 

[soopirV]

Do you plan to eliminate the annoying button we have to press and wait for green light, or is there a mod to bypass it ? A on/off switch that we can arm when the bay is closed will be less annoying.

I'm not particularly bothered by it, but I don't see why you couldn't remove the tactile pushbutton and replace with leads to a more-accessible switch, would that help?

 

[conman13]

ummmmm you dont have to hold the button down at all. press it on to get the ready light and then when the TX is connected to 4 satellites the green light will automatically turn on. no need to hold it down.

 

[Area66]

ummmmm you dont have to hold the button down at all. press it on to get the ready light and then when the TX is connected to 4 satellites the green light will automatically turn on. no need to hold it down.

it's very annoying, you can't place the eggfinder in the Ebay because of the proximity of the altimeters, so I place it in the nose cone, this is very annoying to drill a hole in the nose cone to power the eggfinder or to have to assemble the nose cone bay on the pad.

 

[Area66]

I'm not particularly bothered by it, but I don't see why you couldn't remove the tactile pushbutton and replace with leads to a more-accessible switch, would that help?

yes a lot, this is what I will do with my second one.

 

[chuck5395]

it's very annoying, you can't place the eggfinder in the Ebay because of the proximity of the altimeters, so I place it in the nose cone, this is very annoying to drill a hole in the nose cone to power the eggfinder or to have to assemble the nose cone bay on the pad.

What I do is power up the Eggfinder when I'm still at my work area before heading to the pad. This allows me to verify GPS lock before heading out to the launch pads and is one less thing to worry about at the pads. The battery I use can power the Eggfinder for several hours, so I'm not worried about it going dead on the pad. YMMV.

 

[soopirV]

What I do is power up the Eggfinder when I'm still at my work area before heading to the pad. This allows me to verify GPS lock before heading out to the launch pads and is one less thing to worry about at the pads. The battery I use can power the Eggfinder for several hours, so I'm not worried about it going dead on the pad. YMMV.

What is your power source? I fly 9v alkaline, and get about an hour or so.


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[Area66]

What I do is power up the Eggfinder when I'm still at my work area before heading to the pad. This allows me to verify GPS lock before heading out to the launch pads and is one less thing to worry about at the pads. The battery I use can power the Eggfinder for several hours, so I'm not worried about it going dead on the pad. YMMV.

I will go with the SoopirV idea because I want to prep my rockets days before go to the field.

 

[Wayco]

What I do is power up the Eggfinder when I'm still at my work area before heading to the pad. This allows me to verify GPS lock before heading out to the launch pads and is one less thing to worry about at the pads. The battery I use can power the Eggfinder for several hours, so I'm not worried about it going dead on the pad. YMMV.

I also use this technique. My battery is a 2c LiPo, 7.4v 900mAh. Will run the Eggfinder for hours. I turn it on and prep my rocket while it acquires satellites and locks.

 

[chuck5395]

What is your power source? I fly 9v alkaline, and get about an hour or so.

I use a 2c, 7.4v 300mah Lipo Pack.
https://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=28646

I'm pretty sure I've run it for a least four hours as a test.

 

[ksaves2]

it's very annoying, you can't place the eggfinder in the Ebay because of the proximity of the altimeters, so I place it in the nose cone, this is very annoying to drill a hole in the nose cone to power the eggfinder or to have to assemble the nose cone bay on the pad.

Hi Gerard, Did you try a proximity test with your deployment electronics and it failed? Just curious. I was going to do a 38mm minimum diameter
dual deploy with the EF riding on top of the sled with the antenna projecting into the nose cone and the deployment altimeter riding underneath.
Was going to blow the apogee and have the chute restrained by an Archtype cable cutter. https://lkal32.blogspot.com/p/cable-cutter.html
The main charge would blow the cable cutter and allow the chute to unfurl.

If the EF doesn't play well with proximity, might have to go with a conventional dual deploy with upper and lower parachute bays so to get some distance between the tracker and the altimeter. Kurt

 

[Area66]

Hi Gerard, Did you try a proximity test with your deployment electronics and it failed? ...Kurt

Well no but I want to standard all my rockets with Tracker or GPS in the nose cone, I plan to use way more powerful transmitters than the one use on the Eggfinders, so I want to make sure my rockets will be design for them. I will remove the push button and replace it with lead to be connected to a rotary switch at the bottom of the nose cone, so I just have to lift the cone to arm the altimeter.

 

[soopirV]

Well no but I want to standard all my rockets with Tracker or GPS in the nose cone, I plan to use way more powerful transmitters than the one use on the Eggfinders, so I want to make sure my rockets will be design for them. I will remove the push button and replace it with lead to be connected to a rotary switch at the bottom of the nose cone, so I just have to lift the cone to arm the altimeter.

View attachment 174851

Hi again- just wanted to confirm that we're speaking apples and apples- you mention altimeter at the close, but the eggfinder needs time to acquire 1S lock, so turning on and then pushing the go-button may not be the best. I spoke with Cris after testing my EF on the bench, and he confirmed that it's possible to put another LED in parallel to the indicators to give an external indication that power and lock are still valid. Definitely want to keep the current low on the externals, which may limit your brightness. And I haven't tried this yet, but that may be more what works for you. External activation and confirmation, right?


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[ksaves2]

Hi again- just wanted to confirm that we're speaking apples and apples- you mention altimeter at the close, but the eggfinder needs time to acquire 1S lock, so turning on and then pushing the go-button may not be the best. I spoke with Cris after testing my EF on the bench, and he confirmed that it's possible to put another LED in parallel to the indicators to give an external indication that power and lock are still valid. Definitely want to keep the current low on the externals, which may limit your brightness. And I haven't tried this yet, but that may be more what works for you. External activation and confirmation, right?


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Ahhhhhhhh, why bother? One can see the valid data packets coming in on whatever tracking program they're using. You don't need to see
an LED or go through the bother of an external one. I dorked the red and yellow LEDs on one of my units and it still works fine. The yellow LED I dorked
ripping a trace trying to remove a 1/4watt 330ohm resistor to replace it with the 1/8 watt one and the red LED was dorked as I turned the unit on to test and a stray, clipped component lead lying on my bench shorted it out. I figure I get the green go light and use less battery current ;-) Kurt

 

[cerving]

This is true of ALL radio devices... if you put the antenna next to a significant mass of metal, it will degrade the performance. Doesn't matter if it's an Eggfinder, TeleMega, or your favorite FM radio station.

it's very annoying, you can't place the eggfinder in the Ebay because of the proximity of the altimeters, so I place it in the nose cone, this is very annoying to drill a hole in the nose cone to power the eggfinder or to have to assemble the nose cone bay on the pad.

 

[fyrwrxz]

This is true of ALL radio devices... if you put the antenna next to a significant mass of metal, it will degrade the performance. Doesn't matter if it's an Eggfinder, TeleMega, or your favorite FM radio station.

Chris, i have to say a public thank you for taking the time to demonstrate and explain the capabilities of your system(s) and am still shaking my head at how dense, complex and capable your unit is at this price point. It was truly a pleasure meeting you and can testify to the fact Wayco got off more flights at attitude than I thot humanly possible in one day. Kudos to anamazing pqackage of engineering and thanks for your contributions to our sport.

 

[matthew]

I flew my Eggfinder to 14881' on Sunday. I have the stock wire antenna on the Tx, and a cheapo 3.5dB rubber duck on the Rx. I use an HC-06, and Rocket locator on Android. The Tx is mounted in the nose cone. The package worked flawlessly. I was excited about the launch and wasn't really thinking straight. I confirmed I was receiving data at the pad, and then left the reciever in my pants pocket rather than holding it up or whatever to make sure I had signal during the flight. I watched the launch and saw the smoke from the apogee event. It was then that the column of smoke from the motor drifted over me, so I got out from it but had lost sight of the rocket. Checking Rocket Locator, I could see it was descending at about the right speed for being on drogue. Another silly thing I did - the map was zoomed right out. I thought it was descending almost right above us, but it was actually 2.4km away. In any case, when I was over the initial elation and confusion and actually read what was on the screen, I drove straight to the rocket. The Eggfinder paid for itself many times over, and worked perfectly with basic antennas. I will be buying more! Thanks again for a great product, Cris.

 

[Wayco]

This is great news! Amazing that the stock antenna would work so well at that altitude. Now I can fly mine in my Dark Star Extreme for my L-3 flight with confidence.

 

[conman13]

Wow I want to see what it can do if your using a rubber duck antenna for both the TX and RX.


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[Zeroignite]

Has anyone actually hit a range limit on the stock whip antenna?

 

[cerving]

I haven't, and everybody that I know that's flown higher (above 8,500') has elected to go with a rubber duckie. I think for most people, if you keep the whip on the transmitter and use a rubber duckie on the receiver you'll probably be able to pick it up as high as you're ever likely to fly unless you have some MD all-CF 75mm beastie.

 

[KenRico]

I bought two antennas today and a HC-06 .

Next up some lipos and of course getting them soldered up.

Kenny

 

[Wayco]

Wow I want to see what it can do if your using a rubber duck antenna for both the TX and RX.


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Not sure I have a rocket that will go that high, YET!

I haven't, and everybody that I know that's flown higher (above 8,500') has elected to go with a rubber duckie. I think for most people, if you keep the whip on the transmitter and use a rubber duckie on the receiver you'll probably be able to pick it up as high as you're ever likely to fly unless you have some MD all-CF 75mm beastie.

And we will be testing that theory with our new Mongoose 75....

I don't think anybody can really nail down performance in this case, too many variables. I'm already impressed with the results we have gotten with our Eggfinder, and matthew just put the icing on the cake for me.

 

[ksaves2]

Not sure I have a rocket that will go that high, YET!



And we will be testing that theory with our new Mongoose 75....

I don't think anybody can really nail down performance in this case, too many variables. I'm already impressed with the results we have gotten with our Eggfinder, and matthew just put the icing on the cake for me.

Simply use a decent antenna on the transmitter mounted in the nosecone. I hear the Mongoose nosecone is radio-lucent so that shouldn't be a problem.

If possible, have more than one EF receiver monitoring the flight. Have one with a patch antenna and one with a decent duck antenna to compare to. If one has a third receiver with a wire antenna, can compare all three receivers. (Although, I believe a flyer mentioned in the past, with wire antennas on both ends they lost the packets past
8500' but picked them up on the way down. Would be interesting to see what a higher gain transmitting antenna
would do with a wire receive antenna.)

If one wants to be really scientific. Do a flight with a lower powered motor first, within sight, to see how the rocket
descends after the apogee charge. If the rocket components descend horizontally from apogee, one would want to orient the receive antenna in a horizontal fashion to match polarity. If the upper bay/nosecone descends more or less vertically, hold the receive antenna vertically to match polarity and improve the prospect of receiving packets at the fringe. Then really launch the thing out of sight and orient
the receive antenna to best match polarity on the way down.

My impression is with a more efficient antenna system, the range is going to be a lot farther than currently stated. Kurt

 

[Wayco]

Kurt, didn't you find a magnetic base omni-directional antenna that had about 25 db of gain? I thought you posted a link to it.
I have the 5 db rubber duckie antenna on both my transmitters, and use the same on the RX unit. The unit Cris gave me has the same. I have two receivers, one linked by bluetooth to my Android, and the second one has the LCD screen. I just got another HC-06 but am wondering if I should use both in close proximity to each other. The second unit could pair up with my laptop if they don't interfere with each other. I could use the Android to hunt down the rocket, and keep the LCD receiver as a base station in the truck with the laptop.