I use a DC-DC converter to lower 12V down to 5V for the entire circuit.
Would a dedicated 7805 for the pots be a "meaningful" improvement?
I'll have up to 10 pots in the final circuit. Right now I'm trying to get 1 ADC working well.
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Re: How can I reduce ADC drift
I use a DC-DC converter to lower 12V down to 5V for the entire circuit.
Would a dedicated 7805 for the pots be a "meaningful" improvement?
I'll have up to 10 pots in the final circuit. Right now I'm trying to get 1 ADC working well.
My Creality Ender 3 S1 Plus is a giant paperweight that can't even be used as a boat anchor, cause I'd be fined for polluting our waterways with electronic devices.
Not as dumb as yesterday, but stupider than tomorrow!
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Re: How can I reduce ADC drift
the first step is to measure the noise on the power rail and then to determine if that's an issue, there is no point adding a regulator for the pots if the adc pos reference is noisyWould a dedicated 7805 for the pots be a "meaningful" improvement?
Warning I'm not a teacher
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Re: How can I reduce ADC drift
Based on the fact that you are using Power Supply as a reference voltage for the ADC:
1. the Power Supply noise is random and in the length of time it would have very minimal effect on the adc average value.
2. you are feeding the ADC input from a resistor divider that is connected to the Vdd, where also the reference voltage is connected to. It is called ratiometric and should zero the effect of regulator voltage drift. If the voltage of the Resistor divider changes by x % then the reference voltage will change by x % too. So eventually no drift should happen.
What you experience is strange and should not happen.
Needs more investigation.
If you heat or cool the PIC chip, is there any change?
Ioannis
P.S. If you finally use external Voltage reference, that is reasonably stable, I feel that the results will be even worse, because then the Vdd change will have maximum effect on the voltage sample.
Last edited by Ioannis; - 31st October 2024 at 09:55.
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Re: How can I reduce ADC drift
The Vdd that resistors are connected to, is the exact same point that PIC Vdd pin is connected also?
Ioannis
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Re: How can I reduce ADC drift
Originally Posted by Ioannis
Yes, it is.
My Creality Ender 3 S1 Plus is a giant paperweight that can't even be used as a boat anchor, cause I'd be fined for polluting our waterways with electronic devices.
Not as dumb as yesterday, but stupider than tomorrow!
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Re: How can I reduce ADC drift
Temperature (heating or cooling PIC) has any effect on the drift?
Ioannis
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Re: How can I reduce ADC drift
I'm curious how can this help me?
It is room temperature, just like target customer environment (gaming).
It's not like I'm overclocking the PIC like a PC CPU...?
My Creality Ender 3 S1 Plus is a giant paperweight that can't even be used as a boat anchor, cause I'd be fined for polluting our waterways with electronic devices.
Not as dumb as yesterday, but stupider than tomorrow!
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