Getting to Know Egg Finder GPS

The Rocketry Forum

Help Support The Rocketry Forum:

TXWalker

Member
Joined
Dec 10, 2019
Messages
16
Reaction score
4
Location
Texas
Yesterday was my first flight using my Egg Finder GPS. Good and Bad news. First the bad news. I overstuffed the parachute and it failed to deploy. The rocket came in hard and landed tail first. Rocket is a little banged up but will fly again. The Egg Finder worked perfectly until it hit the ground. The GPS module popped off the board so it was no longer sending a signal on the ground. I used the last received GPS signal in the field to find the rocket. The Rocket was about 134ft up range toward the pad from the GPS waypoint in tall grass. I don't think I would have recovered it without the GPS.

Questions:
1) What iPhone App do you recommend for tracking? I'm using onX Hunting App and it is not ideal. You manually enter GPS coord and it will guide you to waypoint.
2) I want to try to replace the GPS module. Anyone know the part number for the module. I see them on eBay and want to make sure I get the right one.
2) I built the TX unit with an on-board data logger and micro SIM card. I was able to recover the SIM card and using GPS Visualizer display a 2D track on Google Earth. GPS Visualizer will display 2D altitude. I would really like to be able to show a full 3D track.

Thanks in advance.
 

n27sb

N27SB
TRF Supporter
Joined
Jan 30, 2015
Messages
325
Reaction score
98
I would check with Cris for a replacement. Most likely you have other damage on the board so carefully examine it. If it popped off you may have had poor solder joints.
As far as Apps, I use MotionX however I also have the GPS version tracker that Cris offers. It is very simple and works well.
 

TXWalker

Member
Joined
Dec 10, 2019
Messages
16
Reaction score
4
Location
Texas
Steve, I should have been a little more clear. The GPS module is still on the board, my solder joints are OK, the factory solder joints to the patch antennal let go. It looks like they used double back tape to secure the ceramic antenna on top of the module.

MotionX doesn't seem to be available on iPhone.
 

n27sb

N27SB
TRF Supporter
Joined
Jan 30, 2015
Messages
325
Reaction score
98
MotionX doesn't seem to be available on iPhone.
You are correct it looks like they pulled it. Maybe you can find someone with an old phone that has it installed.
It's a shame, it is a great App. I will check my old Iphone and see if it is still there.
Consider setting up an LCD tracker with the added GPS module.
IMG_7733.PNG
 

n27sb

N27SB
TRF Supporter
Joined
Jan 30, 2015
Messages
325
Reaction score
98
It looks like they used double back tape to secure the ceramic antenna on top of the module.
Bummer, I guess that means you have to unsolder the old module base. Possible if you have a hot air de-solder tool. Hit Cris from EF and maybe he has a solution. The GPS module is the bulk of the cost of the kit. You could end up replacing the GPS and still not have a working unit. Over the years I have drilled a few into the ground and they have all survived. We have soft ground here in Fl. Although they can not transmit out when they are underground.
 

n27sb

N27SB
TRF Supporter
Joined
Jan 30, 2015
Messages
325
Reaction score
98
I case you did not pick it up, Timbucktoo shared this link
 

Nick Hutton

Well-Known Member
Joined
May 9, 2019
Messages
64
Reaction score
50
Location
QLD, Australia
I assume you super glued the antenna to the gps body as instructed in the kits. This is a known issue that has been posted about several times. It is apparently near impossible to repair, though one person has posted that they managed to wire a separate antenna to the gps body. Unless you have ninja level soldering skills, getting the gps module off and replacing it successfully is a very difficult task I understand. Cris is likely to give the best advice however.
 

TXWalker

Member
Joined
Dec 10, 2019
Messages
16
Reaction score
4
Location
Texas
I sent a PM to Cris to see what he has to say about reworking the GPS module. I found them online for under $20. First step is to break out the hot air gun and see if I can get the module off without wrecking the board.

Any advice on a good 3D plotting software for GPS tracking?
 

beeblebrox

8 C6-0, 12 D11-9, 20 D20-0, 20 E5-0, 3 Cinerocs
Joined
Mar 19, 2016
Messages
577
Reaction score
169
Location
West Chester, PA
Yesterday was my first flight using my Egg Finder GPS. Good and Bad news. First the bad news. I overstuffed the parachute and it failed to deploy. The rocket came in hard and landed tail first. Rocket is a little banged up but will fly again. The Egg Finder worked perfectly until it hit the ground. The GPS module popped off the board so it was no longer sending a signal on the ground. I used the last received GPS signal in the field to find the rocket. The Rocket was about 134ft up range toward the pad from the GPS waypoint in tall grass. I don't think I would have recovered it without the GPS.

Questions:
1) What iPhone App do you recommend for tracking? I'm using onX Hunting App and it is not ideal. You manually enter GPS coord and it will guide you to waypoint.
2) I want to try to replace the GPS module. Anyone know the part number for the module. I see them on eBay and want to make sure I get the right one.
2) I built the TX unit with an on-board data logger and micro SIM card. I was able to recover the SIM card and using GPS Visualizer display a 2D track on Google Earth. GPS Visualizer will display 2D altitude. I would really like to be able to show a full 3D track.

Thanks in advance.
No need for an app, get an Eggfinder LCD. It is a self contained unit which guides you right to your rocket.
 

Kelly

Usually remembers to get the pointy end up
Joined
Apr 26, 2010
Messages
242
Reaction score
120
Location
Oregon
I assume you super glued the antenna to the gps body as instructed in the kits. This is a known issue that has been posted about several times.
wait, what? I put together an Eggtimer TRS and didn't see anything about this. Is this still the recommendation? Where is this documented?
 

cerving

Owner, Eggtimer Rocketry
TRF Sponsor
TRF Supporter
Joined
Feb 3, 2012
Messages
3,646
Reaction score
882
The GPS antenna is held on with a single solder joint, and conductive tape to the metal ground can. That's pretty typical for small patch antennas... they're not designed to take high-G decelerations. We recommend running a bead of good epoxy (West, RocketPoxy, etc.) around the base of the antenna where it meets the metal can, I've had them survive some pretty gnarly lawn darts when prepared this way.

On the matter of repairing the antenna, you can not... about a 99.99% chance that it took the plate-through on the GPS module's circuit board with it when it came off. The fix is to replace the GPS module... email me if you need further details. You'll need a hot air rework tool.

A lot of people like using phone navigation apps with their LCD receiver so they can get a map, but honestly maps have not been all that useful to me personally. Maybe it's the places that I launch at... it's either desert/lakebed and pretty featureless, or farmfield (TCC) with no marked roads. The GPS option in the LCD receiver points you to where you need to go, and that's good enough for me.
 

cerving

Owner, Eggtimer Rocketry
TRF Sponsor
TRF Supporter
Joined
Feb 3, 2012
Messages
3,646
Reaction score
882
wait, what? I put together an Eggtimer TRS and didn't see anything about this. Is this still the recommendation? Where is this documented?
It might not be in the TRS assembly docs since they have not been updated for some time... I'll take a look at it.
 

Dipstick

Well-Known Member
TRF Supporter
Joined
Jan 21, 2009
Messages
522
Reaction score
113
Not sure if you have cell coverage, but I just type the lat/long from my LCD into Google maps...

Some day I'll buy the LCD addon to get there with one unit.
 

dvdsnyd

Well-Known Member
Joined
May 9, 2012
Messages
127
Reaction score
13
The LCD GPS addon is really nice.
I like the app Compass 55 for iphone to back that up to get a phone display. It isn't fancy, but helped me recover a rocket in the corn(midwest flying) before I had the LCD GPS Rx.
 

o1d_dude

'I battle gravity'
Joined
Jan 18, 2009
Messages
7,911
Reaction score
783
Location
Planet Urff
The GPS antenna is held on with a single solder joint, and conductive tape to the metal ground can. That's pretty typical for small patch antennas... they're not designed to take high-G decelerations. We recommend running a bead of good epoxy (West, RocketPoxy, etc.) around the base of the antenna where it meets the metal can, I've had them survive some pretty gnarly lawn darts when prepared this way.

On the matter of repairing the antenna, you can not... about a 99.99% chance that it took the plate-through on the GPS module's circuit board with it when it came off. The fix is to replace the GPS module... email me if you need further details. You'll need a hot air rework tool.

A lot of people like using phone navigation apps with their LCD receiver so they can get a map, but honestly maps have not been all that useful to me personally. Maybe it's the places that I launch at... it's either desert/lakebed and pretty featureless, or farmfield (TCC) with no marked roads. The GPS option in the LCD receiver points you to where you need to go, and that's good enough for me.
You have described our California launch site conditions quite well, young sir.

Snow Ranch, TCC, Lake Lucerne...
 

Greg Furtman

Well-Known Member
TRF Supporter
Joined
Nov 10, 2018
Messages
1,210
Reaction score
565
Location
Webster, Wisconsin
The GPS antenna is held on with a single solder joint, and conductive tape to the metal ground can. That's pretty typical for small patch antennas... they're not designed to take high-G decelerations. We recommend running a bead of good epoxy (West, RocketPoxy, etc.) around the base of the antenna where it meets the metal can, I've had them survive some pretty gnarly lawn darts when prepared this way.
Chris Are you talking about this area?

1594125041535.png
1594125041535.png
 

John Kemker

Well-Known Member
TRF Supporter
Joined
Aug 25, 2019
Messages
1,377
Reaction score
565
That's not the GPS patch antenna. That's the transmitter antenna to send telemetry back to your phone/receiver/LCD module/etc. The GPS will be that small, beige, square piece.
 

Greg Furtman

Well-Known Member
TRF Supporter
Joined
Nov 10, 2018
Messages
1,210
Reaction score
565
Location
Webster, Wisconsin
That's not the GPS patch antenna. That's the transmitter antenna to send telemetry back to your phone/receiver/LCD module/etc. The GPS will be that small, beige, square piece.
John, we're are talking about this? So where does the epoxy go?
EggFindet TRS Board.jpg
 
Last edited:

n27sb

N27SB
TRF Supporter
Joined
Jan 30, 2015
Messages
325
Reaction score
98
That's it Greg, take a look at the GPS mini instructions and there are photos. I smear a little epoxy (not JB) where the brown can meets the metal at the bottom of your photo and on the opposite side. Doesn't take much.
 

Keisling

Licensed Practical Rocket Surgeon
Joined
Jan 22, 2017
Messages
198
Reaction score
88
Location
Florida
I run a bead of Rocketpoxy along both sides of mine, like this:
Eggfinder.JPG
 

Charles_McG

Ciderwright
Joined
Sep 12, 2013
Messages
2,617
Reaction score
676
Location
SE Wisconsin
I got my LCD GPS add-on when I had a bad HOPE RF module on a Mini and the repair went sidewise. No more Mini - but the GPS was still working, so I wired it up to the LCD.
 

SecondRow

Well-Known Member
Joined
Jan 29, 2019
Messages
445
Reaction score
254
It might not be in the TRS assembly docs since they have not been updated for some time... I'll take a look at it.
i don’t think it’s in the Tx assembly manual, either. If it is, I missed it for the one I built just a couple months ago.
 

heada

Well-Known Member
Joined
Jan 18, 2009
Messages
3,187
Reaction score
552
Location
Indianapolis, Indiana
Adding epoxy to help support the GPS module is mentioned in the Mini instructions but not the TX or the TRS. I've built the TX and TRS and just got 2 Minis but haven't started building them yet.
 

SecondRow

Well-Known Member
Joined
Jan 29, 2019
Messages
445
Reaction score
254
I’ve only got BSI 30 min, JB weld and some Devcon 5 min. Looks like the JB and Devcon are not recommended. Will the BSI work?
 

ksaves2

Lifetime Supporter
TRF Lifetime Supporter
Joined
Nov 25, 2009
Messages
5,835
Reaction score
239
I found this out the hard way the first time. Unit was but 20 minutes old working just fine when a battery cable flexed and flipped the just built unit off the windowsill. The GPS patch antenna snapped off the base. When that happens folks, that’s all she wrote and not repairable....... Unless one has the appropriate desoldering equipment or is able to slice through the base with a cut-off wheel very carefully and then desolder each side separately. I saved the unit that way but use an outboard GPS unit that connects to the pads with wires. Took me awhile to do it as it sat in my junk box for a long time before a eureka moment. Kurt
 

Kelly

Usually remembers to get the pointy end up
Joined
Apr 26, 2010
Messages
242
Reaction score
120
Location
Oregon
I'll take a look at it.
This seems like a tough fix, for the TRS. I could probably get a tiny bead of epoxy along the right hand side, along the edge of the board. But if I apply any to the top, bottom, or left-hand side, it's going to cover up solder pads and/or other components, if I use fillets like Dave showed on the eggfinder. This would make portions of the board non-repairable. Or do I apply the epoxy with a needle tip or something, so that it all stays on the GPS component? Was there some other solution mentioned, like wicking cyanoacrylate under the antenna?

What is the recommendation, for this specific board?
 

Nick Hutton

Well-Known Member
Joined
May 9, 2019
Messages
64
Reaction score
50
Location
QLD, Australia
This seems like a tough fix, for the TRS. I could probably get a tiny bead of epoxy along the right hand side, along the edge of the board. But if I apply any to the top, bottom, or left-hand side, it's going to cover up solder pads and/or other components, if I use fillets like Dave showed on the eggfinder. This would make portions of the board non-repairable. Or do I apply the epoxy with a needle tip or something, so that it all stays on the GPS component? Was there some other solution mentioned, like wicking cyanoacrylate under the antenna?

What is the recommendation, for this specific board?
I did mine a couple of weeks ago. Wasn’t that hard. Used a toothpick to apply some 5 min epoxy. Didn’t cover any of the pads
 

cerving

Owner, Eggtimer Rocketry
TRF Sponsor
TRF Supporter
Joined
Feb 3, 2012
Messages
3,646
Reaction score
882
I recommend using a toothpick and just running a bead between the antenna and the metal can that it connects to. You do not have to glue it to the PC board, you just need a large enough bead to cover the slot between the antenna and the metal can. Potting the whole GPS module in RocketPoxy or similar would probably keep the antenna from coming off too... of course, it might detune the antenna, too, especially if you use a metal-bearing epoxy like JB Weld (which I do not recommend for that reason).
 

Keisling

Licensed Practical Rocket Surgeon
Joined
Jan 22, 2017
Messages
198
Reaction score
88
Location
Florida
I used Rocketpoxy on my TRS, same as the Eggfinder. It's non-conductive so I don't worry about it getting on solder pads.
 
Top