Hi guys, I'm building a small project with Arduino Nano. Basically i'm using analogRead() and analogWrite() to alter a signal from my.
So far so good, the circuit is working fine, all caps and resitors are OK but it seems to have a problem with reference voltage
I've tried using 7805 or 78L05 but the reference voltage still jumps from 4.98v to 5.02 . In my case this is a problem because even 0.1 volts can cause the engine to stop.
It seems that the internal reference voltage in the arduino is not 5.00 but something like 4.80-4.96... In that case this is not working since on two different arduinos the internal reference is different.
I found this function to measure the internal 1.1 reference voltage and calculate the Vin (Vin should work for me) https://github.com/cano64/ArduinoSystemStatus
Well if i change the Vcc voltage from 4.6 to 5.12 for example the internal 1.1 changes too . So in the end analogRead and analogWrite are not in the specifications .
So i want to read a sensor that is from 0 to 4.7 volts with high precision . ADC with 10bits is fine for me , but the reference volgate still bothers me. I don't want to use batteries .
Any ideas ? Maybe external voltage for reference or should tinker the 1.1 volt internal reference ?