Faulty reads from sensor after change PSU

[gebrey]

Faulty reads from DHT22 sensors after I changed PSU from 230V>5V samsung phone charger to this DC-DC step down (https://www.aliexpress.com/item/33019167151.html).

Setup:

• dc source
• arduino nano
• 4pin SPI to LCD2004
• 8pin Digital IO to DHT22 sensors
• 2pin 5V DC to DHT22 sensors

Could some ripple voltage affect the readings?
It's odd since that DC DC has USB port too (that would mean use it with usb stuff like phones etc).

Have you experienxe with bad (not regulated) DCDC?

Is phone charger a REGULATED 5V output?

Thanks

[camsysca]

What is your DC source plugged into the DCDC stepdown?

[gebrey]

12.8V nominal LIFEPO4 BATTERY

Usually 13V passing trought a 40A fuse, Magnetothermic switch and then trought a 5A fuse.

All negative are in common (ground).

[gebrey]

I'm analysing the DC DC module.

The semiconductor are:

• mosfet D4184 (https://www.aosmd.com/res/datasheets/AOD4184A.pdf)
• ic rzc7512 (http://www.rzcsemi.com/guige/usb/RZC7512V2.2.pdf)
• ic CX8571 (Synchronous Constant Current Buck DC-DC IC ..... )

[gebrey]

Ok. I think the problem is unregulated power source, compared to a phone charger that is used to power a wide range of devices, imcluded sensitive stuff.

A LM317 1.5A source probably works better. A bit disappointed.

I will rry with 1000uF cap at output