SparkFun Forums

[Jul12n]

I have a problem with the openlog artemis. I want to log serial data over the rx/tx pins and power it with a LiPo Battery.
The datalogger works great while connected to my laptop but when I let it run over the battery no serial data gets logged to the sd-card.
I have connected a 450mAh LiPo Battery to the pins of the JST Connector with a switch in between to turn it on and off. There is as well a simblrtk2blite from ardusimple connected to the ground and 3.3V pins from the ola.
The battery is connected over the switch before disconnecting from my computer. I have also tried restarting the ola and as well the "stop logging" by pulling the pin 32 to ground (after enabling it in the settings) before reconnecting with my computer.
I'm pretty sure I have connected the battery right after measuring the voltage and the simplertk2blite works fine.

I am very grateful for your help.

[PaulZC]

Hi,

I suspect this is a battery voltage issue. I suspect the battery voltage is dropping low enough to cause the OLA to go into "power loss protection" and go to sleep. The ZED-F9P on the simpleRTK2B Lite can draw 130mA while in acquisition.

I would suggest:

Try a larger capacity battery if you have one. Check the polarity first - some batteries have the same JST connector but the opposite polarity. Use a SparkFun battery if possible.

Try the "No Power Loss Protection" version of the firmware. You can find it here: https://github.com/sparkfun/OpenLog_Art ... n/Binaries . v2.5 is the latest. Upgrade instructions are here: https://github.com/sparkfun/OpenLog_Art ... UPGRADE.md .

Try a different microSD card. Some cards draw more current than others. Maybe it is the combined draw of the microSD and ZED-F9P that is causing the issue.

I hope this helps,
Paul

[Jul12n]

Thank you for your fast response.

I have now uploaded the firmware "OpenLog_Artemis-V10-v25-NoPowerLossProtection.bin" and used another microSD formatted with your recommended software.
I have disconnected the ZED-F9P and instead sent serial data externally by a arduino to reduce the current draw. Again I tried with restarting and "stop logging" after disconnecting and reconnecting with my pc.
At the JST pins I measure 4.2V from the battery which should be enough.
The dataLogs.txt get written while only connected to battery, so I don't think the problem comes from OLA going into sleep
Again the serial logging works great while connected to my pc but doesn't work while connected only with the battery.

Are there any other suggestions I could check?

[PaulZC]

Hi,

Please check the LEDs, while connected to the PC and while operating from battery. Are the LEDs lit and flashing the same in both cases? The STAT LED indicates when data is being written to the microSD card. Does it continue to flash at the same rate when on battery?

Best wishes,
Paul

[Jul12n]

Hello,

The STAT LED is flashing the same for the dataLogs.
For serialLogs the STAT LED flashes when connected to PC and doesn't flash at all when only connected to battery.

[PaulZC]

Hi,

I tried a test with a ZED-F9P connected to the OLA: GND->GND; 3V3->3V3; ZED-F9P UART1 TX -> OLA RX. I set the Serial logging baud rate to 38400. I enabled Stop Logging on pin 32. I tried logging with the OLA connected to my PC via USB. And I tried a separate test with a 1000mAh LiPo battery - with USB disconnected. For me, everything is working. I see NMEA data logged correctly in both cases.

I do not know what else to suggest.

Best wishes,
Paul