So I've been working on a project for my fishtank. In the fishtank there is a temperature sensor and a pH sensor. These are connected to an arduino Uno WiFi board along with an RTC module, SSR and a nextion display. The following is connected to the SSR: lights, heater, pump (all for the fishtank).
When I'm measuring the pH in the calibration liquid, or any other liquid at all, I'm receiving stable readings. When I put the pH sensor in the fish tank and turn anything on (lights, heater or pump), the measurements starts to go up and down and isn't stable anymore. In the circuit there is also a 100 uF and 100 pF capacitor. Am I missing something or is there a way to prevent this from happening?
That 100pF is going to do nothing it should be a 100nF ceramic capacitor, sometimes called a 0.1uF capacitor.
The long leads on the capacitor make them very much less affective. They should be placed on each module.
It is interference from your mains operated devices that is causing the problem. This is down to u tidy wiring and lack of noise suppression on these devices especially the motor,
First of all, thanks for the response. Sorry, but I'm rather new with noise filtering etc.
The temperature sensor is digital, the pH sensor is analogue. The ADC reference voltage is 4.95V if I'm not mistaken.
So if I'm reading correct, I should place multiple 100 nF ceramic capacitors? Should I place them between the VCC and GND or should I place them over the data line from sensor to the arduino? If I remember correctly, the ceramic capacitors should be placed closely to the arduino?