Keg Cop: Keg Monitoring and Control

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LBussy
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So I'm not familiar with GitHub and how it works...that's the 2nd 'issue' raised due to my fumbling around. Is that just like a notepad to remind you of the problem?
It gives me a list, but most importantly it allows me to attribute code changes and releases to the issues in which they were raised. For larger projects, I can set up boards, etc.
 

duncan.brown

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This is an electrical engineering question, not beer question, but I noticed that you have both 1uF and 0.1uF decoupling capacitors between 5V and ground. How is the noise with just 0.1uF? I usually only use the lower value based on this post (and a 100nF on its own generally working):


If the answer is "it depends, buy a scope" then, damnit, you've given me a great excuse to buy a scope... :yes:
 

duncan.brown

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Nice, the excuse I was looking for!

I was looking at the Siglent Technologies SDS1102CML which has two channels and 100 MHz camping for under $300, although the 200 MHz SDS SDS1202X-E is only $50 more and has great reviews. Let me know what you got.
 

day_trippr

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[...]maybe @day_trippr can tell us why that combo is magic.
It's a fairly generic approach that's been around since the TTL and through-hole package days. The two values broaden the frequency coverage of either alone, and as decoupling capacitors historically were only slightly more expensive than tap water the only hold-backs were board space. Even then, given 0201 and even 1005 SMT package sizes, that still wasn't a problem even when I retired last year :)

Cheers!
 

duncan.brown

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Thanks, I figured the combination of the two resonances would give a broader frequency range for the filtering, I was curious how much was needed. At < 10c for a cap, more is probably better. Lee has forced me to buy an oscilloscope*, so I’ll run some tests on the 5V line and see how much noise there is with one and two caps when switching the digital lines.

* that’s my story and I’m sticking to it when my wife asks.
 

duncan.brown

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I also misread that blog post that I posted above... I thought they were looking at adding 1uF to a circuit that already has a 100nF decoupling capacitor, but they were looking at either 1uF or 100nF and... duh, the 100nF is better at suppressing higher frequency noise because the pole is at a higher frequency.

Well, scope ordered. Be nice to finally own a digital one as my last one was an analogue CRT scope that my dad brought me for Christmas from the local army surplus store many years ago...
 
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Lee has forced me to buy an oscilloscope […] that’s my story and I’m sticking to it when my wife asks.
Your wife won’t be the first one to be pissed at me. Hell, I’ve got a few of my own.

Share the scope captures when you get them, I never actually tested that. Dave told me he “sprinkles [decoupling caps] around like candy” so ever since then I do the same. I know I’m off on the skinny branches when he tells me “vaya con dios” so I pretty much do what he says.
 
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