[Help] Arduino Sensor Limits

Good day,

I have an Arduino Uno and i'm wondering how many sensors it can support with high accuracy.

I am building a garden monitoring system and I have 3 moisture sensors, 3 water pump solenoid powered each by a 10A relay, and 1 DHT22 sensor. All are siphoning power from the board's 5V pin.

I noticed that when all components are attached, the moisture sensors and DHT22 are giving inaccurate readings. Everything appears to be fine when I only attach 1 moisture sensor, 1 solenoid, and the DHT22.

I am considering powering all the sensors from a different power rail. However, that will be a big hassle for my design as it will require a secondary power source.

Please help. Looking forward to your responses.

Thanks.

kidlat14:
All are siphoning power from the board's 5V pin.

Double plus ungood!

kidlat14:
I am considering powering all the sensors from a different power rail. However, that will be a big hassle for my design as it will require a secondary power source.

But the processor will be much happier.

kidlat14:
All are siphoning power from the board's 5V pin.

Nonsense! The Arduino's 5 V pin is not a source of power other than perhaps, a few LEDs at 20 mA. Certainly not relays. :cold_sweat:

I do wonder what you mean by "moisture sensors". The term "high accuracy" is essentially meaningless in that context. The DHT22 is digital, so accuracy of the Arduino is not a consideration.

What makes you think you can ask a question without telling us - citing with Web inks - what parts you are actually trying to use? The only things you have described so far are a UNO and a DHT22; we know nothing about the others. :astonished: