Voltage fluctuating too much. How to fix?

[hfp777]

I was thinking that maybe I should make a separate power line for the buzzer and the LCD backlight as they are drawing too much current? Or maybe put the two sensors on their own 5V regulator and all the rest on a separate 5V regulator?

[hfp777]

Would that solve the problem? What about the ground lines, does it matter if I power the sensors from a separate 5V regulator but ground them to the Arduino's pin?

[whitemechanical]

I have read your comments as you mentioned that you put together to monitor the temperature of your fridge and freezer. It might seems that it may take so much power due to which voltage fluctuation is so high. If you are facing this issue continuous then you should contact to a residential HVAC system maintenance professional immediately to fix issue.

[allanhurst]

Both within +/- 5% - OK.

I'm surprised that with  9v on Vin that the 5v isn't more stable - the AMS1115 specs are very good.

And your stuff , even with backlight takes <<50mA - well within specs for both current and dissipation.

It might be worth adding a capacitor to smooth your +9 - say 100uF?

Allan

[Wawa]

whitemechanical answered to a 5½ year old post.
Leo..