Need help powering my project! Any pointers would be greatly appreciated[solved]

Hello everybody! I was hoping someone could point me in the right direction as I have been struggling with this for weeks and I know the concept is most likely well documented, but I’ve had no luck finding it.

Basically, I have a working prototype of a GPS data logger using my Arduino Uno and an Adafruit Ultimate GPS module. I would like to be able to put the GPS module into automatic datalogging mode and then detach it from the Arduino circuit. Using this more compact/portable configuration, I can then map an area and plug the GPS back into the circuit for data processing.

Can the battery powering the GPS be left enabled in parallel when integrating the GPS back into the circuit or is some additional circuitry needed to disable the external battery and buffer the noise (something like a UPS?)?

Also, can the RX/TX pins of the GPS be left floating or should they be pulled to either GND/VCC when disconnected from the microcontroller? I am not seeing an indication of this in the datasheet.

Thank you in advance for your assistance!

Hello all. BUMP for subject clarification. (Perhaps I’m in the wrong forum). I’ll take even a stern tongue lashing at this point to point me in the right direction.

Hopefully my problem is stated clearly, but since I’ve had no luck searching the forum and google, maybe I’m asking the wrong questions.

Seems to me this would be the same power consideration for serial and USB configurations as well.

Thank you so much for your time!

Read the forum rules.

Don't Bump, your thread can be removed by the moderators if you do this.

Also, can the RX/TX pins of the GPS be left floating or should they be pulled to either GND/VCC

Normally it doesn't matter if serial lines are not connected

Can the battery powering the GPS be left enabled in parallel when integrating the GPS back into the circuit or is some additional circuitry needed to disable the external battery and buffer the noise (something like a UPS?)?

I'm not entirely sure what you are worried about.

Just google for Arduino battery and possibly include the keyword gps as well

Its been done by thousands of people already, you are not re-inventing the wheel

You most likely do NOT want to connect power rails together.

Rather than some complicated switching mechanism, you could make sure the GPS is always powered from the battery. Your connector simply has RX, TX, and ground.

It's probably safe to leave the serial pins floating, but if they're just TTL serial (no RS232 converter) it probably wouldn't hurt to use a weak (100K or so) pulldown.

OK.

My bad. I didnt read the spec on the

Adafruit Ultimate GPS module

I presumed it was just a regular GPS module not one with onboard microprocessor which would need its own power supply

A sincere thank you to you both, rogerClark and macegr. My financial backer, aka my wife, won't allow me to buy all new equipment if I fry these modules doing something stupid. I really was having difficulty finding a solution and perhaps it was because I was being too specific; sometimes you don't know what you don't know! Hopefully I'll be up to speed really soon and able to contribute to this great community.

Read the forum rules.

Don't Bump, your thread can be removed by the moderators if you do this.

I had carefully read and thought I was following the rules. If this is no longer an acceptable practice, please update the rules to clarify:

Don't bump your thread after an hour. Because of the different time-zones the person who knows the answer may be asleep, or away for the day. Maybe after a couple of days.

If your question didn't get an answer, honestly review it to see if you posted enough information to help people answer you. Did you even ask a question?

This was solved by doing:

macegr:
You most likely do NOT want to connect power rails together.

Rather than some complicated switching mechanism, you could make sure the GPS is always powered from the battery. Your connector simply has RX, TX, and ground.

It's probably safe to leave the serial pins floating, but if they're just TTL serial (no RS232 converter) it probably wouldn't hurt to use a weak (100K or so) pulldown.