Eggfinder Mini Power problems

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Xionone

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Hi, I have assembled and successfully ground tested an Eggfinder Mini GPS with a 2S 200mAh lipo at over 300 M when the tx in my car.

However when I connect anything else to the Lipo - even just a single short wire to a Quark 0v terminal - the Mini seems to struggle to even transmit data across my workbench - the red led on the Tx is still flashing and the GPS lock led is lit but either no data received or the GPS repeatedly disconnects and reconnects every few seconds (as seen in the Rocket Finder app - Bluetooth option for the receiver). Remove the connection to the Quark and GPS data is clean and consistent.
I tried (as a test) to run the system from a 2200mAh 35C Lipo to see if the (small) battery was at fault - no improvement.
I have tried stranded and solid Cat5 cable pairs, short and long lengths for the wiring, - upto 125mm - no good.
I tried just one wire connected to the Quark cut off switch - the Mini still 'failed'.

I have had email conversation with Cris - he was helpful (as usual:)) but could only really advise shortest possible twisted pair leads from the battery to the Mini - it works perfectly with short leads / twisted pair direct to the battery but I was hoping to use a single battery to power the Mini and the Quark.

I think I may be missing something☹, I have run out of ideas, so I thought I'd ask the great pool of knowledge this forum has proven to be.

As there are many experienced Eggfinder product users out there I was hoping someone had the definitive answer - can you run a Mini GPS on a common battery with other components (eg Quark), if so does anyone have details, pictures, description etc of the configuration?

Of course it could be a bad assembly (self built) - but it works so well when its 'lonely'.

Ta,

D
 
Is there a reason to not just use 2 batteries? Lipos are small. If the battery goes dead, then your altimeter won't function and safely recover your rocket.
 
What is the voltage of that 200mAh battery my guess would be that as it acquires satellites and draws that 200mA your voltage drops below the 4.5v minimum leading to it power cycling. Also you should use individual battery's for each computer just in case one fails or runs out of power you still have a chance of recovery or at lest finding it.
 
Hi, No I don't think a voltage problem after testing with the larger lipo.
The 200mAh Lipo is a 2S 20C drone battery - capable of 8A for 1 sec' and 4A continuous - I rated it for use with the Quark.

Yep, dual batteries is more prudent but I was trying to minimise body length and mass - I have ordered extra batteries as I think I will end up using 2 anyway:(.

Thanks for the input,

D
 
From your description this seems very odd.
Can you post a few pictures of the connections when using one LiPo.
 
Maybe your problem isn't the Mini, it's the Quark. Measure the current draw with only the Quark... I bet you have a "soft short" somewhere (one that's enough to draw excess current, but not enough to draw the voltage down below the operating voltage). Feel the Quark's regulator... does it feel warm/hot to the touch?

Then do the same with the Mini.
 
Hi Cerving, thanks for contributing but it's not the Quark - problem occurs with just wires/switch attached.

Waltr - damn, I have already dismantled it all - I'll try get some pics of working and not working configs tomorrow (if I get time) and post them here. Thanks
 
If you don't figure anything out between now and then...I have both sitting on the bench at work. Tomorrow I will hook them together to a 2S 300mAh battery and see what happens, can also hook to my bench power supply and measure running currents to see if any oddities in power draw.
 
Hi - update - I have wired it on the bench with similar results - 3 pics:

1: Mini on minimum length wires to a 2S 20C lipo - works perfectly - GPS lock indoors in a few minutes.

IMG_6081.JPG

2: Attached pin switch (+V line) and Quark - wired direct to battery socket pins - safety pin in = Quark off - data is less reliable.

IMG_6082.JPG

3: Quark activated and giving all expected beeps - GPS connected to app but no data stream at all - this is worst I have seen, I normally I get some data then a disconnect...reconnect repeating cycle.

IMG_6084.JPG

In all 3 cases the red led on the Tx was doing as expected (short and long(ish) flashing) but in conditions where its being flaky (pic 2 and 3) the green led on the receiver only briefly flashes each second or so (no short/long(ish) flashing mirroring the Tx).

As there is definitely a reliability problem with single battery - even if we work out the cause of the problem I have lost confidence in the single battery design I was planning - I will be using 2 separate batteries for the AV module - damn just added 45mm and 20g to my skinny BT50/55 build.☹, but have added a bit of redundancy :)

Capture.JPG
Bump near nose is an Astrocam. Planned upto F motors.

D
 
Sounds like the GPS module on the Mini is working and sending data to the RF module. Seems like maybe it is the RF module having issues when the Quark is connected (Green LED on RX indicates received data from RF module).

If I remember correctly (Cris please verify) the RF module's antenna has a single connection, angle bracket screwed onto PCB. So the counter-poise is the miniGPS's Ground including the negative battery lead. Could it be this is being upset by the Quark's connection?

Another Test:
Connect the eggtimer Data to USB to the Mini's serial pins. Does the data go bad when the Quark is connected?
If not then the GPS module is working and suspect it is the RF module.

Re-check ALL the solder joints on the RF module. Reflow any that may be suspect.

I do see that you did not solder on the Serial connector to the MiniGPS. You do needs this to re-set the Frequency & ID of the Mini & RX. Not good to leave this at the default - if you are at a launch where someone else also left it on default then you could be tracking the other's rocket.

Cris suggested measuring Current Draw of each, Quark & MiniGPS.

Not hard to do by putting a small vaule resistor in series with the battery.
10 Ohms should work. Then measure the Voltage Drop across the resistor. Ohm's Law then tells you the current: I = E/R or Voltage Drop divided by Resistor value equals the current in Amps.
 
Ok...tested my "stuff"
EGGFINDER-Mini
Quark (with 10ohm resistors in outputs)
EGGFINDER-lCD w/ bluetooth & GPS
Turnigy 2S 300mAh
Andriod app "Rocket Locator"
20220127_160343.jpg

1st. Log file for Eggfinder-mini only.
Only 1 error in the first string as "rocket locator started...then no errors

2nd. Log file with Mini + Quark common wire only connected. No errors in data.

3rd. Log file with Mini + Quark "chirping" in "ready to launch mode". Only 1 error in the first string as "rocket locator started...then no errors

So I would guess there is an "issue" you haven't found yet in yours...I would fly with this arrangement....
Let me know if you want any other checks made...

(Too bad your not closer, we could mix-n-match to try to pin down where the issue is )

Mike
 

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I have checked & re-checked but I have just re-re-checked all the RF module joints - and re-soldered all just in case - re-checked all other joints. I have also removed all flux residue.
I noticed I had put antenna on upside down - I have corrected that.
I tidied up the connections to the power socket.

It's still flaky when Quark wiring connected (Quark enabled or not).

Checked battery voltage approx' 7.95v (I have no handy low value resistors to measure current) and it dips by about 40mV on each tx cycle (Quark attached or disconnected).

I have removed the main power leads from the Lipo and intended to use the charging plug for the connection. I have new lipo's due tomorrow - I'll try them intact and see if it makes any difference (I doubt it though)

Thanks for all input but I'm beginning to think that I somehow damaged the RF module - I was careful about heating, had esd strap and conductive mat - but that's where my thoughts are going. ☹
I may buy another Mini Tx, just to see if it behaves properly.

Re programming - I am in the UK and there are very few Eggfinders here at the moment (I only know of 2 others at my club) and we have to use a fixed single frequency of 869.525MHz.

I'll discuss ID's at next club meet.

D
 
This is a stretch. Looking at the photos, are you using the LiPo's balance connector on the battery for main power? If so, there may be some circuitry used for balanced charging that may be causing some issues. Again just a thought.
 
Thanks Kevin,

That's something I'm going to look at when new batteries arrive - but I think that the 'charger/output current' limiter circuit is not usual on high output power lipos - I have other small lipo's (for my Adrel alt and homemade beepers) that utilise the control chip.

All inputs welcome.

D
 
Oops - I had forgotten - I had tried it with a 2200mAh lipo with no improvement in operation - certainly no charger chip in that one.

D
 
Given the proximity of the two units I would be checking if the receiver wasn't being overdriven, if you haven't done it already. Give a little more space (next room maybe?) and see if things improve.

Personally I think using a 1S is asking for problems and would go higher in voltage for reliability. Others have mentioned this upthread too.
 
Hi there,

I had observed with my copter that GPS reception became impossible, for example, just by switching on a camera.
If the reception disappears when additional cables are connected, this could indicate an external source of interference.
 
Hi ya: All contributions welcome - thanks.

OTT: Yep, tried that when I first saw issue - 1M or 100M range still the same.

RalfB: I tested the system in the middle of a nature reserve, couple of miles form 'civilisation' - so it's prob' not external interference.
 
I do have a miniGPS and just built another Quark yesterday.

I'll also try running both from one battery today. Will post results.
 
@waltr did you see my post #11 above? ( Another data point is a good idea, if that is what you are after. ) I tested and worked fine. No lost "strings" in the log files. One per second in cell phone log file from "Rocket Locator App".

So am I lucky that it works, or does @Xionone have an issue? .... let's see what you find.

Mike
 
@waltr did you see my post #11 above? ( Another data point is a good idea, if that is what you are after. ) I tested and worked fine. No lost "strings" in the log files. One per second in cell phone log file from "Rocket Locator App".

So am I lucky that it works, or does @Xionone have an issue? .... let's see what you find.

Mike

Yes I did and why I decided to test this combination.
Just another data point, so to speak, and see If the problem can be reproduced by someone else.

My Eggfinder RX does not have Bluetooth so will need to open and connect the Serial to USB cable.
May also try different combinations of battery connections.

One difference is the OP's RF modules are on 869.525 MHz (EU) rather than the 915MHz ours are. Should not be an issue.

I did ask him to connect the Serial cable to the header on the MiniGPS to see if the data between the GPS and RF module is good. The blinky LEDs do indicate this but wanted it to be verified.

Have a big snow storm today so no outside testing.
 
Yeah, it was snowing and COLD when I tested too. That's why its on the windowsill. Our work is a stucco outside with metal mesh, so I only get a little reception at the windows, and it takes a while to lock-in. If I go outside it locks-in much quicker.
 
Just got to run tests of MiniGPS with Quark connected.
Worked perfectly, always got good data with and without the Quark connected.
Picture shows the connections.
 

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Sorted it - I eventually got hold of a UART cable to check the data streams - damn dodgy RF module, works perfectly for a few minutes and then data transmission slowly becomes garbled - data from the GPS is all good.

Now a challenge for me: remove the RF module without damaging the PCB.

Thanks all for your contributions.

Denis.
 
Ok, at least you know the GPS is good.
Solder wick should pull most of the solder from the RF module's pads.
Then the module should come off.

An alternative method is lots of solder across all the pads so that they are all molten. Then lift off and clean pads with solder wick.

Good luck and please post back with results.
 
I was able to remove an RF module using low temp solder made for this purpose, something like this:
https://www.amazon.com/SMD-Chip-Removal-Alloy-REMKIT/dp/B08KJKHCJK You just get a big enough blob of this to bridge the row of pads on each side, and it stays molten long enough to enable you get both sides molten and the module comes right off.
 
Hi, I managed to get module off - solder sucker first then sliding an insulator under the module edge one (heated) pad at a time. I had used masking tape under the module so it was just off the pcb. Only hassle was the epoxy I used to reinforce the GPS module had leaked through holes under the edges of the RF module - so the edges were 'half epoxied' to the pads.
Attached a UART and the module accepts and retains commands.
Downloaded the config from the module to program a new one when it arrives.
Control codes are all available from the Hope datasheets.
I'll update when I have the Mini re-assembled - expected date for delivery of new RF module is Thursday :(
 
Hi, I managed to get module off - solder sucker first then sliding an insulator under the module edge one (heated) pad at a time. I had used masking tape under the module so it was just off the pcb. Only hassle was the epoxy I used to reinforce the GPS module had leaked through holes under the edges of the RF module - so the edges were 'half epoxied' to the pads.
Attached a UART and the module accepts and retains commands.
Downloaded the config from the module to program a new one when it arrives.
Control codes are all available from the Hope datasheets.
I'll update when I have the Mini re-assembled - expected date for delivery of new RF module is Thursday :(
Where did you buy the RF module from? Be careful if you get them from eBay... most of them have the 3DR firmware burned into them and won't work with the Eggfinder system. You need the factory firmware.
 
Hi all - success - I replaced the RF module (re-programmed Rx and Tx to an alternate UK legal frequency) and it's now running reliably with 'long' wiring and Quark connected/disconnected.

Thanks for all your inputs.
 
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