Eggfinder and LCD Receiver Build Thread

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Time to button up the initial build on this project, and stuff the receiver into its case. I'm going to go with a different layout than the suggested instructions. Mine's getting a 90 degree turn, and pushing the LCD as far to one side as I can. Why? Because the stock antenna will then fit inside the case.

eggfinder-078.JPG


Started off by finding the location, and drilling one hole. This let me get the locations for the other four holes.

eggfinder-079.JPG


With the holes drilled, I could then flip it over and lay some tape on it that allowed me to mark out the location of the LCD screen.
Normally using tape like like this helps to keep the cuts clean and prevents scratching the material......

eggfinder-080.JPG


But, I don't have the best tools for cutting the hole. I initially tried with a steel ruler and x-acto knife, and things went downhill pretty fast. I eventually remembered I have a dremel tool with a diamond cutting wheel. I was able to get the hole but I really butchered it up badly. What I should have done was wait till Tuesday, bring the cover to work, and hog it out on the mill. It's been a while since I've cut plastic this thick. This is embarrassing. But that's ok, I have a plan!

eggfinder-081.JPG
 
First things first though, I need to get it all mounted up. I used the provided screws and clear tubing to make spacers, but I used 1/8" instead of 1/4" lengths between the LCD and the front cover. Then 7/16 between the LCD and receiver board, and another 1/8" piece between the receiver board and nuts. Battery case is mounted with some double sided tape. I can open it up and change batteries in this location without messing up the tape.

eggfinder-082.JPG


Back side gets a 1/2" hole for the power switch on the battery case.

eggfinder-083.JPG


Then I got busy with the CAD software and 3D printer to make up a bezel for the front side of the case. In person the patterning from the printer isn't as visible, the joy of flash photography.
It does give it a bit more flair, while covering up the hackjob I did cutting the hole, plus recesses the display a bit more. Antenna nestles nicely inside the case, so no risk of damage there either.

eggfinder-084.JPG


I do have a few ideas for upgrades in the near future. An external switch for the LCD backlight, external piezo buzzer with switch, external antenna mount. If I progress too far I'll probably do a whole new case. For now though, I'm ready to go flying!

-Hans
 
Cris, two questions about the EggFinder TX.

1. I built my TX with the RP SMA connector and planned on using a commercial antenna. I've now decided that for flights under 10,000 feet or so I won't bother. I have soldered the kit supplied wire to a connector, but now realise I need to trim the wire. The kit instructions say to measure 80mm from the edge of the board, question is do I include the area that is soldered to my plug or measure after it?

2. I want to add a super cap to the TX to prevent it powering down due to high Gs. It would be convenient to use the 3.3v output for this, but I suspect it would be better it wire it to the battery inputs instead. Could you please provide advice on this? I understand there is a modification to have it power up without the button press but as I already built it I'm not confident about desoldering so would like to consider the super cap option.
 
Cris, two questions about the EggFinder TX.

1. I built my TX with the RP SMA connector and planned on using a commercial antenna. I've now decided that for flights under 10,000 feet or so I won't bother. I have soldered the kit supplied wire to a connector, but now realise I need to trim the wire. The kit instructions say to measure 80mm from the edge of the board, question is do I include the area that is soldered to my plug or measure after it?

2. I want to add a super cap to the TX to prevent it powering down due to high Gs. It would be convenient to use the 3.3v output for this, but I suspect it would be better it wire it to the battery inputs instead. Could you please provide advice on this? I understand there is a modification to have it power up without the button press but as I already built it I'm not confident about desoldering so would like to consider the super cap option.

1. The 80mm would be from the last grounded point. You can make a removable wire antenna by getting a MALE RP-SMA connector (like you'd use for making a cable that mated to the FEMALE connector on the board), and simply soldering the wire into the socket pin before you put it into the connector. Trim 80mm from the end of the connector, and heat-shrink the element so it can't short against the ferrule. I personally have yet to fly a TX with anything other than the wire antenna, although I know a bunch of people that use the Linx Technologies ANT-916-CW-QW antenna... that plus a good half-wave on the LCD are good for well over 20,000'.

2. It would be fine to wire the super cap to the 3.3V pads. If your battery gets disconnected, there's no other path for the current to go except through the Eggfinder's circuitry. Of course, the super cap could get disconnected in flight too...

The only way the TX is going to shut off in flight is if the power gets disconnected. Anchoring your battery down and tying the wires down to the sled with zip ties will fix that. With the B4 board, if the button somehow got held down for a whole second that would shut it down too, but that's unlikely (unless you wrap the TX in foam and stick it in the nose cone that way... which I do not recommend).
 
Cris, two questions about the EggFinder TX.

I understand there is a modification to have it power up without the button press but as I already built it I'm not confident about desoldering so would like to consider the super cap option.



It's easier than you think. I modified three older units. If you can solder you can desolder. Good quality desolder braid is a must. You can always practice on old circuit boards.
 
1. The 80mm would be from the last grounded point. You can make a removable wire antenna by getting a MALE RP-SMA connector (like you'd use for making a cable that mated to the FEMALE connector on the board), and simply soldering the wire into the socket pin before you put it into the connector. Trim 80mm from the end of the connector, and heat-shrink the element so it can't short against the ferrule. I personally have yet to fly a TX with anything other than the wire antenna, although I know a bunch of people that use the Linx Technologies ANT-916-CW-QW antenna... that plus a good half-wave on the LCD are good for well over 20,000'.

Just to be clear, the last ground point is square part at the end of the socket?

346c0d40b180d860f8bc60c8ad5d6d78.jpg
 
I've choosen a Rose Bopla enclosure #29214000
Digikey part # 902-1023-ND, about 60 dollars. But very nice and tough as nails.

Lots of room inside for other options and a 1000ma 2S lipo and charging circuit( 12V.)..

11850590_973494236045451_1375769007764258862_o.jpg
 
Welp, I guess I'm appropriately intimidated now. We'll see how the LCD build goes; if I end up cursing too much, I may farm out the Tx build.
 
I'm really glad this old post popped up again. I somehow missed it on the first go-round, and there is some excellent info here. :cool:
 
I found the v2 of the EggFinder an easier build than the v1 unit. I did find the v1 easier to work with if the gps module breaks. The auxiliary 3.3V terminals on the board made it easy to wire an outboard GPS module for a repair.
Only takes one connection to the GPS pad for the input signal. Kurt
 
Quick question for cerving and/or other Eggfinder users:

I just finished my build of an Eggfinder TX and LCD. Everything appears to work, except the 1S amber LED on the TX. I still get good data and a good link between the TX and LCD, as far as I can tell in my backyard. My best guess is that the LED was either bad or I damaged it somehow (like 95% certain I installed it the right way). But given that everything else works, I'm loathe to mess with the board. Any quick and relatively non-invasive things I should check?

If I have a non-functional amber LED, will that actually hurt anything else?

Also, in the instructions for the LCD, it mentions that all TXs use the ID 0 setting. But in the new users guide for the TX, it seems to imply that the ID can be reprogrammed along with the frequency using the LCD reprogramming option. Can I set my TX to different IDs (I know our club has at least a few Eggfinder users)?

Finally, a suggestion for cerving: if you revise your users' guide for the LCD, please make the contrast trim pot setting step a bit more obvious. My screen was all black and it took me forever to figure out the trim pot - I thought I broke something. It is extremely annoying to have to remove the LCD module any time you want to adjust that pot - but that would be a much harder fix.
 
The 1S LED is actually a timebase indicator from the GPS, you can get a valid fix without the LED coming on, although if it DOES come on then you most definitely have a fix. The ultimate fix indicator is your LCD display.

Check page 24 of the Eggfinder TX/RX User's Guide for instructions on changing the frequency & ID of the TX (it also changes the LCD receiver to match).

You should only ever have to adjust the LCD contrast once, you'll note that there's a little hole behind it in the PC board so you can put a small screwdriver in there to adjust it without removing the display or powering down. But yes, I'll put a little more prominent verbage in the manual.
 
Thanks for the quick response! Now I feel dumb for not noticing the hole behind the trim pot.

I'll let the TX sit outside a bit longer and in better conditions next time before I jump to any conclusions about it.
 
OK, package is on its way and I'm excited to get rolling with this.
Does anyone have a recommendation for an inexpensive LiPo charger? I got a USB-powered one that appears to be DOA (get what you pay for when you spend $10 on a LiPo charger, I guess). I've seen them for anything from $10 to $200, I'd like something much closer to the $10 range....
 
Wow, fun to see my older posts getting bumped up. Ironically the next version came out right after I finished this build.

Glad you guys were able to find it useful.
 
I gotta genuine B6 similar to this: https://hobbyking.com/en_us/imax-b6-ac-charger-discharger-1-6-cells-genuine.html
Thing with lipos is you gotta get nicads and nimh out off your mind. If you aren't going to be using them for awhile
(and I've seen some hardcore users say that means 3 days!) one should put them on a balanced charger and use the
storage "mode". It brings the pack voltage of say a 2S pack to around 7.6V. The pack will store better in this state meaning it will maintain full capacity over time when you do charge it up full and use it.
I've found this out the hard way so no more trickle charging like with other chemistries. Plus you gotta remember that a
pack without overcurrent protection will self destruct in a fire. Kurt
 
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It looks like the Eggtimer website is down - anyone know what's up?

Anyway because of the website I can't access the pdf build instructions - anyone know of a copy posted elsewhere? I only need the portion re: installing the LCD in the project box.
 
It looks like the Eggtimer website is down - anyone know what's up?

Anyway because of the website I can't access the pdf build instructions - anyone know of a copy posted elsewhere? I only need the portion re: installing the LCD in the project box.

The site is up for me... but TRF won't let me post the 3.5mb pdf file here.

I checked RocketrtFiles.com - but only found eggtimer stuff nothing for the LCD.
 
It just came back up... it was an ISP server issue. I'm sure it took a bunch of other people down, too.
 
The site is up for me... but TRF won't let me post the 3.5mb pdf file here.

I checked RocketrtFiles.com - but only found eggtimer stuff nothing for the LCD.

The Eggfinder LCD stuff is under Eggfinder Support on the left navigation bar. Yes, the site needs to be reorganized... New Year's resolution.
 
The site's still down for me, so thanks for the Wayback link - it was a big help! All but a couple of the manuals were documented, fortunately it included the one I needed. I saved local copies, which I needed to do anyway for the field. Thanks ActingLikeAKid!
 
Apparently it's still down. I spent an hour and a half on the phone with the ISP (well, 1 hour and 15 minutes were on hold...), they had to escalate it. At least they're not offshore...
 
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