The Eggfinder Mini - A Very Small GPS Tracker

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Just do it the way Cris shows and by gosh don't drill the board thinking you'll be able to push mount them. I, like you, was considering the alternatives and was going to drill until I flipped the board over and thought the better of it.
Just bend the header pins, get the center one soldered and go the other two. I was able to tweak the angle by pushing down and nothing ripped off. Don't fly these things at 915, 0 unless you are out in the boondocks and none of your
flying friends have caught on to them. Best to make an odd ball pick and hope no one else is using it. Kurt (built two)
 
I wasn't going to mess with the board. I know Cris puts a lot of work into the desings, but he has to work with what is available... Using small pliers I pushed each pin through the black spacer up to the end. I flipped the center one around and then trimmed the short legs shorter so they would fit centered on the pads.
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then I soldered them down with a good amount of solder, using the black plastic to keep the pins inline...
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Then clipped the pins down to the same height as the LED and GPS unit. this is just enough length to work well with the plugs.
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Nice, I see you kept the profile below the GPS chipset otherwise it wouldn't be able to fit in as small a tube as possible. I take it you re-programmed successfully then.
If I build a third one, your way is the way I'll go next instead of bending. Kurt
 
Yes. A lot of people set all their Eggfinder transmitters to "their" frequency. Of course, some people randomize the frequencies too...

I had a Mini and a TRS going at the same time in my Double Shot, on different frequencies. Worked fine... in fact, the TRS in the nose (with a wire antenna) tracked to over 5 miles away when the main came out at apogee due to loose shear pins. It actually landed on the back side of the surrounding hills... lost signal at about 1000' AGL as it went over the back, found it right where it said it was.
 
Yes. A lot of people set all their Eggfinder transmitters to "their" frequency. Of course, some people randomize the frequencies too...

I had a Mini and a TRS going at the same time in my Double Shot, on different frequencies. Worked fine... in fact, the TRS in the nose (with a wire antenna) tracked to over 5 miles away when the main came out at apogee due to loose shear pins. It actually landed on the back side of the surrounding hills... lost signal at about 1000' AGL as it went over the back, found it right where it said it was.

Awesome!
Yes it sure did! I think it might have been at least 6 miles where you were searching, amazing.
 
Both lights on means that it's in programming mode, there's a line to it from the processor that controls that. Something is locking up somewhere, or shorting. Try reflashing the software, if it won't program then it's a processor issue. Take a look at the resonator to make sure that one of the leads didn't get broken off... I've see that happen.
 
Take a look at the resonator to make sure that one of the leads didn't get broken off... I've see that happen.

It is worth a small dolop of silicone rubber to hold that to something nearby. That's something I normally do for high-inertia components. Remember to use neutral-cure silicone!
 
Both lights on means that it's in programming mode, there's a line to it from the processor that controls that. Something is locking up somewhere, or shorting. Try reflashing the software, if it won't program then it's a processor issue. Take a look at the resonator to make sure that one of the leads didn't get broken off... I've see that happen.

Email sent. Thanks!
 
I just finished my Eggfinder Mini. It smoke checked good and showed itself right where it was supposed to be in my driveway. Next up: adjust the freq on it and my regular Eggfinder and design a 3d printed sled for my Go Devil 29. I also need to put some epoxy on the GPS antenna and a few components on my Eggfinder Quark...high G launches, and all.

Putting the power leads on before the diode worked like a champ. Tinning both pads for the diode felt a bit weird, but it worked.

IMG_0663.jpg IMG_0661.jpg
 
Some additional advice on eggfinder mini assembly:

I started building my eggfinder mini build today. I always have fun building these kits and it is great that these kits are offered to the hobby by a fellow hobbyist! It is a whole new rocket building challenge that I would encourage others to tackle.

I had one little problem attaching the gps unit that I'd like to share with others planning to do this build: I soldered the 4 resistor leads that hold the gps unit in place. These are attached to the edge of the board. The leads might have been bent in a little bit when they were cut because I had to push the gps unit down to get it to seat on the board. As I was pushing the gps unit down one of the leads popped off the edge of the board were it was soldered. When it popped off it took the conductive trace (1/2 via?) that runs from the top of the board to the bottom of the board off with it. I was able to recover by getting the solder to bridge between the top and bottom planes. And now everything checks out when tested with a conductivity meter.

Here is what I want to pass on to others: 1. don't force things together and 2. make sure the resistor legs are supported if you need to make any adjustments or have to bend the legs to get the gps unit located. I was unaware of how delicate the traces that run across the edge of the board are.

Now you know. Good luck and have fun.
 
I had the same issue with the gps being just slightly bigger than where the resister leads were soldered. I ended up removing the leads and lined everything up and held it in place with a very small clip. I then soldered a few traces and flipped it over to do the other side. Once everything was tacked down I soldered it up. Worked fine but took a little time to line things up.
 
It's important to get enough heat on the leads when you remove them so that you don't need apply any pressure... that tends to take off the vias on the edge of the board. The reality is that all four of those corner channels don't connect to anything so if you lift a pad it won't prevent it from working. (Well, one is a ground, but there are huge ground pads on the bottom so if you miss it it's no big deal.) Make sure you get a good solder bond on the GPS pads and the other vias, that will pretty much guarantee the some solder will flow underneath the GPS chip onto the pads below where all the connections are made. And once you test it, glue on the GPS antenna and heat shrink it... the heat shrink protects those solder joints.
 
Same issue on my first Eggfinder Mini, when I pushed the GPS down flush with the board, I popped off two resistor leads and the traces from the board came off with them. On the second and third units I simply soldered two resistor leads on one side, and didn't put the 3rd and fourth ones on the other side. I had no alignment issues and it avoided that issue altogether.

Some additional advice on eggfinder mini assembly:

I started building my eggfinder mini build today. I always have fun building these kits and it is great that these kits are offered to the hobby by a fellow hobbyist! It is a whole new rocket building challenge that I would encourage others to tackle.

I had one little problem attaching the gps unit that I'd like to share with others planning to do this build: I soldered the 4 resistor leads that hold the gps unit in place. These are attached to the edge of the board. The leads might have been bent in a little bit when they were cut because I had to push the gps unit down to get it to seat on the board. As I was pushing the gps unit down one of the leads popped off the edge of the board were it was soldered. When it popped off it took the conductive trace (1/2 via?) that runs from the top of the board to the bottom of the board off with it. I was able to recover by getting the solder to bridge between the top and bottom planes. And now everything checks out when tested with a conductivity meter.

Here is what I want to pass on to others: 1. don't force things together and 2. make sure the resistor legs are supported if you need to make any adjustments or have to bend the legs to get the gps unit located. I was unaware of how delicate the traces that run across the edge of the board are.

Now you know. Good luck and have fun.
 
I'm pretty sure I installed the LED backwards. What is the best way to check? The mini is communicating correctly on 915 MHz and returning GPS data to the LCD receiver but the amber LED on the mini never blinks.
 
I'm pretty sure I installed the LED backwards. What is the best way to check? The mini is communicating correctly on 915 MHz and returning GPS data to the LCD receiver but the amber LED on the mini never blinks.

If you can look closely at the LED you will note a couple of features. The flat section of the body base is on the cathode side. Also, the LED die mounted in the plastic encapsulation has a flag shape at the top of the cathode side lead.

If it is reversed on the board, you can carefully desolder it and flip it around - otherwise you're up for a new LED.

You could also check it with a multimeter with the board power off. Also, check your solder joints at the LED and at the GPS module.
 
Same issue on my first Eggfinder Mini, when I pushed the GPS down flush with the board, I popped off two resistor leads and the traces from the board came off with them. On the second and third units I simply soldered two resistor leads on one side, and didn't put the 3rd and fourth ones on the other side. I had no alignment issues and it avoided that issue altogether.

I found that aligning the GPS module and taping it in place on the board was quite easy and allowed me to solder it on without the resistor leads. Pad registration was spot on. Only a narrow length of tape is necessary, long enough to wrap around the board and GPS module. Solder the 4 corners, remove the tape, then complete the rest.
 
I flipped the LED around and everything works fine now! The spacing on the 3mm LED made it easy. I had a wide soldering iron tip that allowed me to heat both leads at once. Just pulled the LED off as soon as the solder flowed. Then I came back with a vacuum bulb to clean up the holes. I tested the LED once is was off the board to figure out polarity and make confirm it worked.
 
Anyone know the specs on a replacement diode? A7 VH09 gets me nowhere in the google or digikey.
photo.php
 
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Anyone know the specs on a replacement diode? A7 VH09 gets me nowhere in the google or digikey.
photo.php

Contact Cris Erving at Eggtimer he will take care of you.

I got my Eggfinder Mini up and running tonight (at least it appears to be), somehow or the other I managed to cook one of the 103,222, or 3300 resistors, with the spares that Cris includes (and an extra from another Egg project) I replaced them all and voila it seems to work.
 
It's a FM2007, any of the FM2000's will work. Email me with your address and I'll send you one... no sense paying $10 shipping on a 30 cent part.
 
Bump to this thread.
I have some 600mAh 1S lipo batteries that I have been using with a newly assembled Eggfinder mini. It seems to work fine for a basic functional test around the house.
Is there any concerns with using a 1S instead of 2S? Lower range or runtime? I don't know where the voltage cutoff is.

I also tried the same battery on the deployment power of an Eggfiner TRS and it would NOT fire e-matches, so those definitely need the 2S.
 
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