Sparkfun OLA logger serial issue

Hi KPBio,

This sounds similar to this issue:

Please tell me more about your hardware:

What voltage level is your serial device using? It must be 3.3V for the OLA / Artemis. Are you using a MAX3232 chip to convert from RS232 to 3.3V?

Does your serial device keep transmitting data while the OLA is asleep?

Is the OLA providing power to the serial device? When the OLA is asleep, is the serial device powered off?

How ‘busy’ or ‘active’ is the serial device? Does it output data continuously? Or is it like a GPS / GNSS chip and only output data in bursts, once per second?

The issue could be something like:

The serial device TX pin is back-feeding power into the OLA RX pin, causing strange behaviour when the OLA wakes from sleep.

Or, perhaps the voltage levels are not correct?

Best wishes,