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Andrew Kesterson
2026-06-02 10:19:05 -04:00
parent 082f0c092e
commit a23fd56191
1 changed files with 3 additions and 3 deletions
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04-adc/README.md
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@@ -44,7 +44,7 @@ One of the simplest ADCs to implement is called a Flash ADC, and that one is sim
I really wanted to understand how the ESP32-S3 in particular accomplishes this. So I went through a deep dive of the reference manual, plus some googling, plus some GPT interpretation of the TRM, and figured some things out.
<center><img alt="hold on to your butts" width="320">holdontoyourbutts.gif</img>
<center><img alt="hold on to your butts" width="320" src="holdontoyourbutts.gif"/></center>
The ESP32-S3 has two ADCs on the package that both perform in the same basic fashion, but are controlled in slightly different ways. Per the technical reference manual
@@ -240,7 +240,7 @@ By doing this, we eventually wind up with a series of "less than greater than" c
Aaaaaand I'm spent.
<center><img alt="was it good for you too?">wasitgoodforyou.gif</img>
<center><img alt="was it good for you too?" src="wasitgoodforyou.gif"/></center>
The TRM has a ton of information on these peripherals, but I'll be honest, if you're not used to reading TRMs, this can get thick quick. I needed a couple days of digging through the manuals to make sense of it all. But I'm glad I did.
@@ -260,7 +260,7 @@ But a capacitive touch sensor isn't exactly the same as a capacitor. All it is d
Why don't we need some special kind of touch sensor for this to work? I've spent a lot of time using "capacitive touch screens" and was given the impression this technology was something special. Just grabbing onto a bare wire seems ... cheap.
<center><img alt="we have the technology" width="320">cavementechnology.gif</img></center>
<center><img alt="we have the technology" width="320" src="cavementechnology.gif" /></center>
Since the touch sensor is just detecting changes in the rate of charge of a capacitor, all we need is something that will allow us to transmit electrons from one store (our bodies) to the other (the testing capacitor). This can be done by just getting the store (our fingertip) close enough to the wire to form the electrical field that's due to the charge imbalance; this will create a detectable change in the rate of charge of the capacitor. It doesn't even matter if we're grounded or not, because it isn't about completing a circuit with the sensor, it's about getting two charged objects near each other to induce that electrical field that induces detectable change in the capacitor.