Hello, I’ve recently bought an OpenLog board for a highschool engineering project. I have it connected to a UART GPS Chip and 3 1.2 V rechargeable batteries in series. For around 3 days it worked great, GPS data points were logged onto the SD card with no real hiccups.
However, today when I recharged the batteries and put them back in, the OpenLog stopped working. The problem was very much like the post here, the OpenLog would power on, both LEDs would flash once, and then nothing. Also like the post, the OpenLog works fine without the SD Card, the blue LED flashes 3 times in a row which seems to correspond to nothing being inserted. However, unlike the post, the order in which I plug in the batteries and the SD Card doesn’t matter, both cases result in both LEDs flashing followed by nothing.
The first thing I did was swap the batteries, even trying nonrechargeable batteries and a DC power supply, but the error persisted. I tried three different SD cards and I wiped them all down with IPA in case there was something wrong with their contacts. I then attempted what the Artemis post suggested and placed a capacitor across VCC and GND. I tried 22uF, 47uF, 100uF, and even 1000uF capacitors, but still no help. Unfortunately, I can’t try to load new firmware onto the board as I don’t have an FTDI board and as my assignment is due in a couple days, I don’t have enough time to buy one. Regardless, I don’t think it could be the firmware as the board worked perfectly for 3 days prior to today. What could possibly be the issue?
I would try more SD cards if possible (reformatted and whatnot), and maybe take a look at the actual tabs/locking pins on the SD card holder/slot and ensure nothing funky is going on (bent tab, missing tab, a clear non-contact issue, etc)
How low did the batteries get to?
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Tried 3 more SD cards today with no luck. I also inspected the SD slot and saw nothing peculiar. All the contacts were straight and looked like they would make good contact with the card.
When I swapped out the batteries, the module was still logging and working fine. I only swapped out the batteries to see how long a fully charged set of batteries would last me. I had also swapped out batteries previously (changing from standard nonrechargeable batteries to rechargeable ones) and everything had worked as expected.
Which GPS module are you using? Does it use 5v io or 3.3v io?
For the SD cards, are they:
- 64MB to 32GB
- FAT16 or FAT32?
If 3.3v io and yes to both above, it sounds like it might be a dead board - Was it purchased from us? If so head over to Returns (contact vendor if purchased elsewhere) and we’ll get ya squared away
I am using this GPS module, which seems to use a 3.3v IO.
As for the SD Cards, they ranged in size from 4 GB to 32 GB and were all formatted with FAT32. I’ll try a smaller card formatted with FAT16 soon as a last ditch effort to save the board, but I guess the board is dead.
On a side note, any idea what might’ve caused this? Considering the little time I spent with the board, and the fact that everything was working fine at the beginning, I assume that something went wrong.
Well, after looking at that datasheet it looks like it outputs 0.4-2.4v, the openlog wants 3.3v io…usually something within 0.7x of nominal voltage will work, but in this case 0.7 * 3.3 = 2.31v, which is right around the upper limit for the GPS module’s output, so I worry that might be the issue. You can use a logic level shifter to step up the io voltage, which might remedy the situation