I build a data logger with Arduino MEGA, SD, Ethernet, RTC, GSM, display module, and thermal printer. I am facing problem with unregulated power supplies. I have tried many power adapters, phone chargers, led strip power supplies and noone is 5±0.2V regulated. All power supplies are over 5V and are drifting overtime. I tried led power supply with buck converter 5V and the output was 5.4V. The only good power supply was ATX PSU but it is waste of money.
I need a 5V 2.5-3A regulated power supply, how can I find or build one?
Note: The device is going to work continuously over 5 years