@gohan Yep, that did it. Thank you so much.

@sundberg84 I use the example code for all sensors. I am not sure about the mains power fluctuations, how would I check that?

@gohan I changed all the chargers when I first had problems, I hope the problem is elsewhere. I am using 5V 2.5A mini usb chargers

@manutremo I am using NRF24L01+, bought from the ebay link on connecting radio page

I have built several sensors (PIR sensors, dust sensors, and distance sensors) using 5V Nanos that all work but need to be reset every couple weeks because they keep going down. All of them are connected via phone charges to the outlets. I am not sure what the problem is exactly. Some of them are more reliable than others, but it has nothing to do with distance to the gateway as the one closest to the gateway fails just as often as the one furthest from it. What can I do to improve reliability/durability?

@sundberg84 What capacitor would you recommend? I am not sure how I would I filter out the output of voltage regulator, can you provide a bit more detail.

I used the example code provided without any changes. Can I see your code if possible? Thank you.

I have successfully built motion sensors using arduino nanos and plug them into the wall using a 5V USB phone chargers. They work perfectly when they are working, but after about 7-10 days they stop working. If I unplug and plug back in, they work fine for another couple days-weeks.

I have already solder a 4.7µ capacitory on all my radios. I have tried switching the USB chargers, motion sensor, and radios on couple of sensors but no found its didn't solve the issue.

Is it possible to get these motion sensors to work without me having to upkeep them every 2-4 weeks?

@gohan Yep, that did it. Thank you so much.

@gohan I removed the sleep portion, but still can't get the watchdog to trigger a reset
https://hastebin.com/xeqavitadu.cpp

@dbemowsk https://hastebin.com/ilonemimev.cpp
I am using an arduino nano plugged into a 5V phone charger. I can get the watchdog working on its own. But, not when I put the rest of the motion sensor sketch with it.

How do I add a watchdog timer to my motion sensor sketch?
I can get an example watchdog timer sketch to work, and it resets if wdt is not rest in the loop, but I cannot get it work in the motion sensor sketch.