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Precision-Analog-Front-End

LemonAidLee·Precision-Analog-Front-End·KiCAD_PCB_Design/Precision_AFE_ESP32.kicad_pcb

Precision-Analog-Front-End PCB layout, top view — open source ESP32 board by LemonAidLee
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About the Precision-Analog-Front-End PCB

Precision-Analog-Front-End is an open source ESP32 PCB design by LemonAidLee, published on GitHub under the CERN-OHL-P-2.0 license. It is a 2-layer board measuring 78 × 99.5 mm, with 29 components from 18 distinct parts.

Its main chip is the ESP32_LEFT_HDR, from the ESP32 family. Other key parts include the TL082, LM7812 and LM7912. By type, the board carries 7 capacitors, 5 connectors, 4 ICs and 2 resistors.

From the project

A highly precise, ±100 mV analog front-end (AFE) designed for the ESP32 and ADS1115. Features a 4-stage TL082 architecture including a Sallen-Key low-pass filter, delivering 9.4 µV/LSB resolution for precision data acquisition.

A four-stage precision analog front end that conditions a ±100 mV bipolar sensor signal into the 0–3.3 V unipolar window of a 16-bit ADS1115 ADC, designed for an ESP32-WROOM-32 host. Designed, simulated in LTspice, and laid out in KiCad. Not built — no physical hardware exists.

Rev A board (78 mm × 100 mm, 2-layer), KiCad 3D render. The physical board has not been manufactured.

Precision-Analog-Front-End, from the project README
From the project README

Main components on the Precision-Analog-Front-End

TL082LM7812LM7912

Precision-Analog-Front-End bill of materials (BOM)

29 components, 18 distinct parts — part numbers from the project's BOM.

QtyPartRefs
2
TL082
U1, U2
1
LM7812
U3
1
LM7912
U4
1
SENSOR_INPUT
J1
1
POWER_INPUT
J2
1
ESP32_LEFT_HDR
J3
1
ESP32_RIGHT_HDR
J4
1
ADS1115_MODULE
J5
1
5.9K
5.9k
Rf1
1
90K
90k
Rf2
2
30K
30k
Rf3, Rref1
4
10K
10k
Rf4, Rg1, Rg2, Rin2
1
36K
36k
Rin1
2
470
Rref_a1, Rref_b1
3
100n
C1, C2, C3
2
330N
330n
C4, C6
2
100N
100n
C5, C7
2
1.5K
1.5k
R1, R2

Precision-Analog-Front-End design files

The KiCad project lives in the LemonAidLee/Precision-Analog-Front-End repository on GitHub; these links point at the commit this page was built from.

Precision-Analog-Front-End: common questions

What microcontroller does the Precision-Analog-Front-End use?

The Precision-Analog-Front-End is built around the ESP32_LEFT_HDR, from the ESP32 family.

How big is the Precision-Analog-Front-End PCB?

The Precision-Analog-Front-End measures 78 × 99.5 mm, has 2 copper layers and is 1.6 mm thick.

How many components are on the Precision-Analog-Front-End?

29 components, from 18 distinct parts, with part numbers taken from the project's own BOM. The full bill of materials is listed on this page.

Where can I download the Precision-Analog-Front-End design files?

From the LemonAidLee/Precision-Analog-Front-End repository on GitHub, which has the KiCad layout, the schematic and the BOM; the links under Design files point to each one.

Can I use the Precision-Analog-Front-End design in my own project?

Yes, under the terms of its CERN-OHL-P-2.0 license, which LemonAidLee chose for the repository.

Can I test firmware for the Precision-Analog-Front-End without the hardware?

Yes. HardLabs builds a simulation of the board from its netlist and BOM, so you can run and debug ESP32 firmware against it before you order a PCB.

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