ESP32 Analog Sensing (Internal ADC)

What you'll build

Read analog signals with the ESP32's built-in ADC, and learn first-hand why the built-in ADC isn't enough. You'll measure its real noise and nonlinearity and hit the classic ADC1-vs-ADC2 trap: ADC2 pins stop working whenever Wi-Fi or ESP-NOW is active, so every sampled input has to route to ADC1. The lesson that motivates every precision ADC that follows.

It sits on the SENSE track: reading real-world signals and turning voltages, currents, and biopotentials into clean digital data.

Tools for this build

Free calculators that do the math this board needs. Each is worked from a real OTD board, with the formula and a cited source.

• Voltage divider calculator (Vout, R1, R2) →Compute a resistive divider's output voltage and quiescent current from Vin, R1, and R2. Sized for fitting a higher voltage into an ESP32's 3.3 V ADC.
• RC filter cutoff frequency calculator (first-order) →Find a first-order RC filter's −3 dB cutoff (fc = 1 / 2πRC) and time constant from R and C. For ADC anti-alias and noise filtering.

The build pipeline

No steps skipped, no black boxes. Each stage is gated on real proof of work: a clean ERC, valid gerbers, a passing bring-up. You finish having actually done the engineering, not just watched it.

1. 01REQUIREMENTS
2. 02BOM SOURCING
3. 03SCHEMATIC
4. 04LAYOUT
5. 05DRC + GERBER
6. 06ORDERING
7. 07ASSEMBLY
8. 08BRING-UP
9. 09REVISION

Builds on

• ESP32-S3 USB-C Breakout Board→

Questions

When does this course open?

It's in active production. Join the waitlist and we'll email you the moment it goes live, and the demand signal helps us decide what to build next.

Is it beginner-friendly?

This is a foundational L1 board, approachable if you can read a schematic. Every stage is explained from first principles, so you can follow along as long as you're comfortable reading a schematic.

What will I need to build it?

Reading the course is free with a free account. Building the board for real also needs its bill of materials (listed in the course) and a small PCB order from a fab house. The course walks you through both.

What will I actually learn?

You'll learn reading real-world signals and turning voltages, currents, and biopotentials into clean digital data, plus the full board workflow: schematic capture, layout, DRC, gerber export, ordering, assembly, and bring-up.