Hello,
For my last project I need to power my arduino, up to now I thought that two CR2032 coin cells were enough, but after 30 seconds my project is freezing
I use a 0.96" OLED Display and 3 buttons, nothing that requires a big amount of energy but it doesn't works great with this solution.
I read that 7V was needed to power the arduino correctly, is there someone who had the same troubles ?
Thank you
Are you connecting to VCC or the RAW pin?
CR2032 is only intended for 0.0002A (0.2mA) discharge rate, with total capacity of 200 to 210mA.
'328P draws 15-20mA while doing not much. Surprised the CR2032s last 30 seconds even.
This isn't the best method of course, but an arduino nano can also be powered by bypassing the voltage regulator. Plug + of a voltage source about 3.3 - 5V to the 5V pin, source ground to GND. Keep in mind this is obviously going to lower your output pins voltage to the voltage source. If your OLED screen only runs on 5V logic, this probably won't be helpful. This method works best with simple components like LEDS and buttons.
I've used this method to run a simple nano alarm clock on 3.7V.
-Englishscone
Englishscone:
Plug + of a voltage source about 3.3 - 5V to the 5V pin...
The 328 processor of a common 16Mhz Nano is only rated from ~3.85volt at that frequency.
You could have reliability issues below that voltage.
An 8Mhz Arduino works reliably from about 2.7volt (to ~5.5volt), and consumes less power if you remove regulator and LEDs.
A 16Mhz Nano is not the best candidate for coin cell operation.
There are many coin cell powered (ProMini) Arduino projects on Google.
Me thinks the OLED current draw could be your biggest problem.
Leo..
surveyranger:
Are you connecting to VCC or the RAW pin?
Yes, I use the VIN pin on the top of the board
Hi
Welcomed to the forum.
Is this related to this thread?
https://forum.arduino.cc/index.php?topic=621448.0
Please read the first post in any forum entitled how to use this forum.
http://forum.arduino.cc/index.php/topic,148850.0.html . Then look down to item #7 about how to post your code.
It will be formatted in a scrolling window that makes it easier to read.
Can you please post a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png?
Thanks.. Tom... 
CrossRoads:
CR2032 is only intended for 0.0002A (0.2mA) discharge rate, with total capacity of 200 to 210mA.'328P draws 15-20mA while doing not much. Surprised the CR2032s last 30 seconds even.
If I understand your answer, the '328P takes too much power for a Coin cell ?
Englishscone:
This isn't the best method of course, but an arduino nano can also be powered by bypassing the voltage regulator. Plug + of a voltage source about 3.3 - 5V to the 5V pin, source ground to GND. Keep in mind this is obviously going to lower your output pins voltage to the voltage source. If your OLED screen only runs on 5V logic, this probably won't be helpful. This method works best with simple components like LEDS and buttons.I've used this method to run a simple nano alarm clock on 3.7V.
-Englishscone
Your solution is to put the input voltage directly into the 5V pin ? Does the arduino still works ?
TomGeorge:
Hi
Is this related to this thread?
https://forum.arduino.cc/index.php?topic=621448.0
Yes, it's my problems for the same project, I didnt know if it should be posted together or not so I posted twice, I'm sorry if it's not the right way to do it
TomGeorge:
Can you please post a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png?
My circuit is the one in attachment
HI,
Can you post your code please?
Do you have input_pullup included in you pinMode input setup/
Thanks.. Tom..
This helped me a lot. Might not solve the OLED draw.
If you have a regulated 5V power supply it is safe to plug the ground into Arduino GND and the 5V into Arduino 5V.
You may have to cut the connector off the end of the power supply cable if there is one, the Arduino power connector goes through a regulator that expects at least 7V to work -- a regulated power supply does not need a regulator!
Take care to not pull more than 200mA total through the Arduino IO pins in either direction (OUTPUT HIGH or LOW, INPUT uses very little power) and power whatever needs more current directly, not through the Arduino chip.
For more power projects the Arduino pins should control the things that carry/switch the power, like transistors and driver chips. With a relay you can switch house mains power on and off.
I think a Nano is the wrong board for this.
Start with a 3.3V/MHz Pro Mini - less power draw as it doesn't need the USB converter, and you can lower it more by removing the regulator and the power LED. After that you should be able to power it from a single CR2032: 3V to the Vcc pin.
The remaining issue is your OLED display, which likely draws too much current for this to work, you may need to use 2xAA or 2xAAA batteries instead, assuming your OLED works at 2.4V. I'd also be looking at an LCD display (not the 1602, but the 7-segment style ones), those things draw next to no power.
