Reverse flow to USB and automatic deep sleep

Development Boards Artemis
1

Hi, I’m using SparkFun OpenLog Artemis (DEV-16832) and have had very few problems with it.

However, I have two problems.

It’s backflow to USB and automatic deep sleep.

  • backflow to USB

Lithium batteries seem to draw current back into the USB device even when the USB device is off.

Is it possible to prevent this?

  • automatic deep sleep

I confirmed that by entering q and y on the console, the LED turned off and the power consumption decreased.

Is this deep sleep?

Is there a safe timer to go into deep sleep if USB communication is lost, even if I can’t input on the console?

I don’t know the firmware version, but I bought it within a year or two!

Thank you!

2

I believe you’d just need to use a ‘stop logging’ to pull the PSWC low https://learn.sparkfun.com/tutorials/op … iderations and then you can use a timer with the on-board RTC to schedule an awake/reset signal - I’m not sure what part of the circuit is allowing backflow, however https://cdn.sparkfun.com/assets/1/4/e/1 … latest.pdf …you might need to cut the VE jumper? https://learn.sparkfun.com/tutorials/op … e-overview

You can always use a multimeter to test power draw to verify the sleep mode while testing; also if installing a simple switch on the lipo is an option that might work too

Side note: in order to fully charge the RTC battery the OLA needs to be plugged into a power source for ~24 hours (USB or LiPo)…ensure it’s charged before fiddling with longer sleep modes

3

Thank you for your reply!

  • reverse flow to USB

maybe, J2 is powered through D1 to USB 5V. Is this impossible to prevent?

  • automatic deep sleep

That’s right. I can only “stop logging”.

I’m using it for 100Hz communication, but is the only way to reduce current consumption by just “stop logging”?

Also, if “stop logging” fails and the host computer is terminated, is there a way for OLA to automatically lower its power consumption?

By the way, I use it a little differently, generating 4V from a big battery instead of a LiPo and connecting it. In addition, the host computer and other microcomputers are powered off while connected to 5V, but this will operate due to reverse current from 4V, and there are other issues such as wanting to reduce the power consumption of the OLA as much as possible.