VCC is off a ways. How to compensate?

Moderators: grovkillen, Stuntteam, TD-er

Post Reply
Message
Author
User avatar
budman1758
Normal user
Posts: 301
Joined: 15 Apr 2017, 05:13
Location: Riverside CA USA

VCC is off a ways. How to compensate?

#1 Post by budman1758 » 21 Mar 2018, 05:09

I am using the latest mega version (almost every night upgrade :D ) I am displaying the %vcc% variable in an OLED display. I would like to know what the least complicated way is to compensate and display the actual correct voltage is. According to the ESP module the voltage is 3.16 volts. According to my 300 dollar Fluke its actually 3.29 volts. Is it possible to adjust this without using a task for it? If not then use a dummy device? Or is that far enough off to make a Git issue?
"The glass is twice as big as it needs to be".

TD-er
Core team member
Posts: 8643
Joined: 01 Sep 2017, 22:13
Location: the Netherlands
Contact:

Re: VCC is off a ways. How to compensate?

#2 Post by TD-er » 22 Mar 2018, 01:20

Often they use some resistor network, so the offset should be computable :)
The offset is in the order of 4%, which is within the error margin of most (cheap) resistors.
The perfect compensation is probably not a constant factor, but rather some kind of curve, but for getting a very close estimate you could multiply its value by (3.29/3.16 = ) 1.04

User avatar
budman1758
Normal user
Posts: 301
Joined: 15 Apr 2017, 05:13
Location: Riverside CA USA

Re: VCC is off a ways. How to compensate?

#3 Post by budman1758 » 22 Mar 2018, 01:35

The question is more of where to do that though. Do I have to use a task and if so what kind?
As it is now I just put %vcc% in the line of the OLED. I tried to put a formula there but that doesn't work. :?: :?:
"The glass is twice as big as it needs to be".

Post Reply

Who is online

Users browsing this forum: Google [Bot] and 24 guests