RF datalogger can't write into file on microSD card

Hi, I'm new to this so I'll be quick:

I have an arduino UNO reading data from a flowmeter and sending it wirelessly using VirtualWire, another arduino receives the data and is supposed to store it in a text file on a microSD card.

Everything in the receiving arduino works except that it does not write the data in the text file. It can read the transmitted data and open a file in the microSD card, so why won't it write?

Insteak:
so I'll be quick:

Clearly too quick.

I wasn't lying...

What info do you need ?

Insteak:
I wasn't lying...

What info do you need ?

We need to focus our crystal ball on your code and we can't see it from here!

Paul

Paul_KD7HB:
We need to focus our crystal ball on your code and we can't see it from here!

Paul

My crystal ball doesn't even have a focus knob.

I have the same symptoms using a Ardulog-RTC from HobbyTronics. http://www.hobbytronics.co.uk/ardulog-rtc

Just using the supplied sketch, I soldered on a Dallas temp I2C to the board and this reports the temperature correctly via serial. However, although the LOG.001 file is created correctly, the file itself contains no data. Which is odd.

I’ve tried using Sandisk Ultra 16Gb and 32Gb cards, both of which were formatted using the SD Card Formatter as recommended in the sticky. Both cards appear to behave properly as I can save files onto them via Win10. I’ve also run the FlashDrive/Card Tester v1.14 from vconsole.com and they both check OK for the read/write test.

This is the exact card:
http://www.picstop.co.uk/microsd-sdhc/sandisk-ultra-micro-sdhc-memory-card-80mbs-class-10-for-android-with-sd-adapter-16gb.html

HobbyTronics themselves test using a small card - but I can’t readily obtain MicroSD cards less than 16Gb locally (argos/supermarkets - Asda, Sainsburys etc) unless I use preowned eBay etc. Which I don’t want to do! Their support has been good - but I’m stuck on this issue.

Does anyone out there have compatibility tests they carry out?

Incidentally, I have used both these cards on a different project with a Mega connected to a RobotDyn MicroSD card board which worked fine.

Encl: the full sketchbook including above and the other two referenced files. This is also available from the Ardulog-RTC page link above at the foot.

**Update: Tried the Datalogger Sketch from the SD examples, and that works perfectly on the same 16Gb microsd card as above. So there’s possibly a quirk with the sketch above.

ardulog_rtc.zip (5.52 KB)