How can I improve the power supply for my Arduino-based sensor system?

Question

I am working on an Arduino-based sensor system that includes a temperature sensor, a humidity sensor, and an LCD display. Everything works fine, but I am facing issues with power stability when I run the system for extended periods.

The sensors sometimes stop responding, and the LCD display flickers occasionally. I am currently powering the system using a 9V battery, but I suspect that the power supply might not be sufficient or stable enough for continuous operation.

I was considering switching to a regulated power supply, but I’m not sure which type would be best suited for this setup. Should I go with a linear regulator or a switching regulator? Are there any specific products that are recommended for Arduino-based systems?

Additionally, I found this DC-DC Convertor which seems like a good option. Has anyone used something similar in their projects? Any feedback or alternative recommendations would be greatly appreciated.

Thank you!

• fabianoriccardi: May you link the board you are using?

Answer 1

9V batteries may seem convenient but are generally not recommended for systems that run for a long time. An exception might obviously be smoke alarms, but they are specifically designed to have low current draws.

If you are using something like a Uno, and plugging in a 9V battery, then the voltage regulator immediately converts that to 5V, throwing away the rest as heat.

You are much better off using, say, 3 AA batteries in a battery holder (giving a nominal total of 4.5V) and connecting that directly to the 5V pin of your Arduino.

Then I would set it up to sleep, consuming much less power when it is not actually taking readings.

I did a temperature and humidity sensor, described here which runs for a couple of years before needing battery replacement.

I also have some tips for low power usage.

Related post on this site: Arduino minimal power usage

Answer 2

Assuming you want your system to work as long as possible with the battery, you should consider changing your elements:

• Do NOT use Arduino Uno or similar, but go for a Pro Mini (3V3/8MHz) with no LED.
• Select a low consumption display. e-ink are best, as they do not consume anything as long as you don't change the display.
• Look at "sleeping" capabilities of your system. There are a few libraries or articles explaining how you can put your system to sleep and only wake up every x minutes.
• Consider using a 1.5V battery and a boost DC-DC converted.

One AA battery will last weeks if you are following the above recommendations. I have one such system running since 10 years at home, and I change my battery roughly every year.

Answer 3

You can always tie multiple batteries in parallel for more current, use a bigger 9v battery, or go with any 9v power supply. If your sensors are analog, you may need to use a linear power supply because they make less noise. If the sensors are digital, switching should work fine. I think all of the sensors would be 5v, if so, a 5v power supply would work as long as it has enough current to run all the sensors, and Arduino. DC-DC converters aren't really want you are looking for unless your power supplies are too high of a voltage or if you need two separate voltages. With Arduino, I usually connect a 12V power supply to VIN so that I have 12V, and 5v 3.3v from the Arduino. When you connect your sensors, try not to draw too much from the Arduino. The pins can only supply so much.