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Phone board

JamesTwallin·gas_sensor·hardware/phone_board/phone_board.kicad_pcb

Phone board layout, top view — open source ESP32 board by JamesTwallin

About the Phone board

Phone board is an open source ESP32 PCB design by JamesTwallin, published on GitHub under the MIT license. It is a 4-layer board measuring 60 × 33 mm, with 62 components from 32 distinct parts.

Its main chip is the ESP32-S3-MINI-1-N8, from the ESP32 family. Other key parts include the USBLC6-2SC6, BQ24073RGTR, AP2112K-3.3, TPS61023DRLR and ADS1115IDGSR. By type, the board carries 27 resistors, 18 capacitors, 7 ICs, 5 switches, 2 connectors and 1 transistor.

It belongs with the sensors, iot & wireless and power & battery designs in this gallery.

From the project

A 60 × 33 mm, 4-layer board: bare ESP32-S3-MINI-1, two bare Figaro TGS sensors, ADS1115, SHT40 temp/humidity, LiPo charging and a 5 V heater boost. Position, display, storage and signal processing live on the phone. The electrical spec (why each part, pin map, BLE protocol) is do

A 60 × 33 mm, 4-layer board: bare ESP32-S3-MINI-1, two bare Figaro TGS sensors, ADS1115, SHT40 temp/humidity, LiPo charging and a 5 V heater boost. Position, display, storage and signal processing live on the phone. The electrical spec (why each part, pin map, BLE protocol) is docs/phone_board.md.

Status: rev C is the current design, and the one to build. It is rev B compacted, with the same schematic and parts; this layout has not been fabricated yet. Rev B (66 × 36 mm, git tag rev-b) was fabricated and assembled at JLCPCB and passed bring-up on 2026-09-28: it enumerates over native USB…

Phone board, from the project README
From the project README

Main components on the Phone board

USBLC6-2SC6BQ24073RGTRAP2112K-3.3TPS61023DRLRESP32-S3-MINI-1-N8ADS1115IDGSRSHT40-AD1B-R2

Phone board bill of materials (BOM)

62 components, 32 distinct parts — part numbers from the project's BOM.

QtyPartRefs
1
USBLC6-2SC6
U1
1
BQ24073RGTR
U2
1
AP2112K-3.3
U3
1
TPS61023DRLR
U4
1
ESP32-S3-MINI-1-N8
U5
1
ADS1115IDGSR
U6
1
SHT40-AD1B-R2
SHT40-AD1B
U7
1
AO3401A
Q1
1
TYPE-C-31-M-12
J1
1
C295747
LiPo 1S
J2
1
TGS2611-E00
S1
1
TGS2610-D00
S2
1
C431540
POWER
SW1
1
C318884
RESET
SW2
1
C318884
BOOT
SW3
1
WS2812B-2020
D1
1
SWPA4030S1R0NT
1uH
L1
1
10UF
10uF
C1
5
10UF
10uF
C2, C3, C4, C5, C8
2
22UF
22uF
C6, C7
Show 12 more
QtyPartRefs
8
100NF
100nF
C9, C11, C12, C13, C14, C15, C20, C23
2
1UF
1uF
C10, C16
2
5.1K
5.1k
R1, R2
6
10K
10k
R3, R6, R7, R11, R12, R19
1
1.5K
1.5k
R4
1
1.8K
1.8k
R5
1
732K
732k
R8
5
100K
100k
R9, R10, R15, R16, R26
3
1M
R13, R14, R27
2
4.7K
4.7k
R17, R18
4
20K
20k
R20, R21, R23, R24
2
1k
R22, R25

Phone board design files

The KiCad project lives in the JamesTwallin/gas_sensor repository on GitHub; these links point at the commit this page was built from.

Phone board: common questions

What microcontroller does the Phone board use?

The Phone board is built around the ESP32-S3-MINI-1-N8, from the ESP32 family.

How big is the Phone board?

The Phone board measures 60 × 33 mm, has 4 copper layers and is 1.6 mm thick.

How many components are on the Phone board?

62 components, from 32 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 Phone board design files?

From the JamesTwallin/gas_sensor 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 Phone board design in my own project?

Yes, under the terms of its MIT license, which JamesTwallin chose for the repository.

Can I test firmware for the Phone board 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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