# Smart Espresso Scale

## Description

Battery\-powered smart espresso scale with BLE/WiFi\-capable MCU, load\-cell measurement, OLED interface, USB\-C charging, and debug/programming access\.

## Project Details

- **Owner:** natarius
- **Created:** 7/13/2026
- **Last Updated:** 7/14/2026
- **Visibility:** Public
- **Human Interface:** OLED
- **Connectivity:** BLE
- **Domain:** Consumer Electronics
- **Power Requirements:** Battery

## Key Components

### D1 — [SMF5\.0A](https://flux.ai/lcsc/smf5p0a~bz6b.md)

- Package or Case Code: SOD\-123FL\_L2\.8\-W1\.8\-LS3\.6\-RD
- JLCPCB Part Class: Extended Part
- Role Details: 5V TVS clamp for protected USB VBUS
- Datasheet URL: https://www\.lcsc\.com/datasheet/C2990427\.pdf?spm=wm\.sxq\.inf\.ggs&lcsc\_vid=T1kIXgFeT1NaU1RXQFBbUlUHT1cKU1NXFVBeX1VSTlAxVlNRTlBbUVFXRldaXzsOAxUeFF5JWBYZEEoKFBINSQcJGk4dAgUUFAk%3D
- LCSC Part Number: C2990427
- Diode Type: Schottky Diode
- Part Type: TVS
- Role: ESD Protection
- Max Reverse Voltage: 5V
- Manufacturer Name: Liown\(里阳半导体\)
- Manufacturer Part Number: SMF5\.0A
- Forward Voltage: 0\.45V to 0\.55V \(at 1A\)V

**Pins:**
- 1 [pin 1]
- 2 [pin 2]

### D2 — [ESD224DQA](https://flux.ai/kicad-part-library/esd224dqa~nw.md)

- Role Details: ESD protection for low\-level load\-cell connector signals; leakage to verify during layout/BOM review
- Manufacturer Name: Texas Instruments Inc\.
- Datasheet URL: https://www\.ti\.com/lit/ds/symlink/esd224\.pdf
- Package or Case Code: Diodes\_UDFN\-10\_1\.0x2\.5mm\_P0\.5mm
- Manufacturer Part Number: ESD224DQA
- Role: ESD Protection

**Pins:**
- \~ [pin 7]
- \~ [pin 9]
- \~ [pin 4]
- \~ [pin 2]
- \~ [pin 5]
- \~ [pin 6]
- \~ [pin 1]
- \~ [pin 10]
- VSS [pin 8]
- VSS [pin 3]

### D3 — [150060VS55040](https://flux.ai/adrian95/150060vs55040~c2q.md)

- Part Type: LED
- Datasheet URL: https://www\.we\-online\.com/components/products/datasheet/150060VS55040\.pdf
- Manufacturer Part Number: 150060VS55040
- Manufacturer Name: Würth Elektronik
- Role Details: Charger STAT indication LED
- License: https://creativecommons\.org/licenses/by/4\.0/
- Role: Status LED

**Pins:**
- A [pin 2]
- K [pin 1]

### F1 — [SMD050F\-2](https://flux.ai/adrian95/smd050f-2.md)

- Role Details: 500mA hold polyfuse for USB VBUS input
- Datasheet URL: https://www\.littelfuse\.com/assetdocs/littelfuse\-ptc\-smd\-datasheet?assetguid=e664881a\-0c68\-4836\-928b\-7ed2f0c2a6da
- Part Type: Circuit Protection Devices
- Manufacturer Part Number: SMD050F\-2
- Mount: Surface Mount
- Role: Protection
- Manufacturer Name: Littelfuse
- License: https://creativecommons\.org/licenses/by/4\.0/

**Pins:**
- \~ [pin 2]
- \~ [pin 1]

### J1 — [UJ20\-C\-H\-G\-SMT\-2\-P16\-TR](https://flux.ai/adrian95/uj20-c-h-g-smt-2-p16-tr~v05.md)

- Datasheet URL: https://www\.sameskydevices\.com/product/resource/uj20\-c\-h\-g\-smt\-2\-p16\-tr\.pdf
- Manufacturer Part Number: UJ20\-C\-H\-G\-SMT\-2\-P16\-TR
- Symbol Style: parametric\-v1
- Manufacturer Name: Same Sky \(Formerly CUI Devices\)
- Role Details: 5V sink\-only charge input with CC pull\-downs
- Role: USB\-C Power Input
- License: https://creativecommons\.org/licenses/by/4\.0/
- Part Type: Connector
- Mount: Surface Mount

**Pins:**
- CC1 [pin A5]
- CC2 [pin B5]
- DN1 [pin A7]
- DN2 [pin B7]
- DP1 [pin A6]
- DP2 [pin B6]
- GND [pin A1\_B12]
- GND\_\_1 [pin B1\_A12]
- SBU1 [pin A8]
- SBU2 [pin B8]
- SHIELD [pin SH1]
- SHIELD\_\_1 [pin SH2]
- SHIELD\_\_2 [pin SH3]
- SHIELD\_\_3 [pin SH4]
- VBUS [pin A4\_B9]
- VBUS\_\_1 [pin B4\_A9]

### J2 — [S2B\-PH\-SM4\-TB\(LF\)\(SN\)](https://flux.ai/adrian95/s2b-ph-sm4-tblfsn~b96.md)

- Manufacturer Name: JST Sales America Inc\.
- Datasheet URL: https://www\.jst\-mfg\.com/product/pdf/eng/ePH\.pdf
- Manufacturer Part Number: S2B\-PH\-SM4\-TB\(LF\)\(SN\)
- Role Details: Protected 1S LiPo pack connection: BAT\+ and GND
- Role: Battery Connector
- License: https://creativecommons\.org/licenses/by/4\.0/
- Part Type: Connector

**Pins:**
- P1 [pin 1]
- P2 [pin 2]

### J3 — [B4B\-PH\-K\-S\(LF\)\(SN\)](https://flux.ai/lcsc/b4b-ph-k-slfsn~0ffw.md)

- Datasheet URL: https://storage\.googleapis\.com/graviton\-electric\-symbols/document\_assets/lcsc/2304140030\_JST\-B4B\-PH\-K\-S\-LF\-SN\_C131334\.pdf
- Role: Load Cell Connector
- Connector Rows: 1
- Package or Case Code: CONN\-TH\_B4B\-PH\-K\-S
- Part Type: Wire To Board / Wire To Wire Connector
- Connector Positions: 4
- Connector Type: Board to Wire
- Manufacturer Part Number: B4B\-PH\-K\-S\(LF\)\(SN\)
- Role Details: 4\-wire load cell interface: E\+, E\-, A\+, A\-
- Manufacturer Name: JST
- Product Info Url: https://lcsc\.com/product\-detail/PH\-Connectors\_JST\_B4B\-PH\-K\-S\-LF\-SN\_B4B\-PH\-K\-S\-LF\-SN\_C131334\.html
- JLCPCB Part Class: Extended Part
- LCSC Part Number: C131334
- Connector Pitch: 2mm
- Connector Gender: Female

**Pins:**
- 1 [pin 1]
- 2 [pin 2]
- 3 [pin 3]
- 4 [pin 4]

### J4 — [Pin Header 01x04 2\.54mm Vertical i2c](https://flux.ai/hasanbasri93/pin-header-01x04-2p54mm-vertical-i2c~37.md)

- Part Type: Connector
- Role: Display Connector
- Role Details: I2C OLED header: 3V3, GND, SDA, SCL
- License: https://creativecommons\.org/licenses/by/4\.0/

**Pins:**
- 5V [pin 1]
- GND [pin 2]
- SCL [pin 4]
- SDA [pin 3]

### J5 — [AVR\-ISP\-6](https://flux.ai/vasy_skral/avr-isp-6~ry.md)

- Role Details: ESP32\-C3 debug/programming: 3V3, GND, TX, RX, EN, BOOT
- Symbol Style: parametric\-v1
- Role: Programming Header
- Datasheet URL: https://www\.we\-online\.com/catalog/datasheet/61200621621\.pdf
- Part Type: Connector
- Manufacturer Name: Würth Elektronik
- Exclude from BOM: false
- Manufacturer Part Number: 61200621621

**Pins:**
- GND [pin 6]
- MISO [pin 1]
- MOSI [pin 4]
- RST [pin 5]
- SCK [pin 3]
- VCC [pin 2]

### SW1 — [TS\-1088\-AR02016](https://flux.ai/lcsc/ts-1088-ar02016~e3n1.md)

- Role: Button
- Manufacturer Name: XUNPU\(讯普\)
- Datasheet URL: https://storage\.googleapis\.com/graviton\-electric\-symbols/document\_assets/lcsc/2409302330\_XUNPU\-TS\-1088\-AR02016\_C720477\.pdf
- JLCPCB Part Class: Extended Part
- Manufacturer Part Number: TS\-1088\-AR02016
- Product Info Url: https://lcsc\.com/product\-detail/Tactile\-Switches\_XUNPU\-TS\-1088\-AR02016\_C720477\.html
- LCSC Part Number: C720477
- Part Type: Tactile Switches
- Package or Case Code: SW\-SMD\_L3\.9\-W3\.0\-P4\.45
- Role Details: Tare/user zero button to ESP32 GPIO

**Pins:**
- 1 [pin 1]
- 2 [pin 2]

### SW2 — [TS\-1088\-AR02016](https://flux.ai/lcsc/ts-1088-ar02016~e3n1.md)

- Manufacturer Name: XUNPU\(讯普\)
- Datasheet URL: https://storage\.googleapis\.com/graviton\-electric\-symbols/document\_assets/lcsc/2409302330\_XUNPU\-TS\-1088\-AR02016\_C720477\.pdf
- JLCPCB Part Class: Extended Part
- Manufacturer Part Number: TS\-1088\-AR02016
- Role: Button
- Product Info Url: https://lcsc\.com/product\-detail/Tactile\-Switches\_XUNPU\-TS\-1088\-AR02016\_C720477\.html
- LCSC Part Number: C720477
- Part Type: Tactile Switches
- Package or Case Code: SW\-SMD\_L3\.9\-W3\.0\-P4\.45
- Role Details: Mode/timer control button to ESP32 GPIO

**Pins:**
- 1 [pin 1]
- 2 [pin 2]

### SW3 — [Slide Switch SW\_SPDT](https://flux.ai/404src/slide-switch-swspdt~nq.md)

- Manufacturer Part Number: SS12F44G5
- Manufacturer Name: Wealth Metal
- Purchase Url: https://www\.taydaelectronics\.com/slide\-switch\-1p2t\-through\-hole\-0\-5a\-50vdc\.html
- Role: Power Switch
- Datasheet URL: https://www\.taydaelectronics\.com/datasheets/A\-5111\.pdf
- Role Details: Manual system power switch; 0\.5A rated, adequate for estimated scale load but review if adding higher\-current loads

**Pins:**
- A [pin 1]
- B [pin 2]
- C [pin 3]

### SW4 — [TS\-1088\-AR02016](https://flux.ai/lcsc/ts-1088-ar02016~e3n1.md)

- Manufacturer Name: XUNPU\(讯普\)
- Role Details: Manual reset button pulls ESP32 EN low
- Datasheet URL: https://storage\.googleapis\.com/graviton\-electric\-symbols/document\_assets/lcsc/2409302330\_XUNPU\-TS\-1088\-AR02016\_C720477\.pdf
- JLCPCB Part Class: Extended Part
- Manufacturer Part Number: TS\-1088\-AR02016
- Role: Switching
- Product Info Url: https://lcsc\.com/product\-detail/Tactile\-Switches\_XUNPU\-TS\-1088\-AR02016\_C720477\.html
- LCSC Part Number: C720477
- Part Type: Tactile Switches
- Package or Case Code: SW\-SMD\_L3\.9\-W3\.0\-P4\.45

**Pins:**
- 1 [pin 1]
- 2 [pin 2]

### SW5 — [TS\-1088\-AR02016](https://flux.ai/lcsc/ts-1088-ar02016~e3n1.md)

- Role: Switching
- Manufacturer Name: XUNPU\(讯普\)
- Datasheet URL: https://storage\.googleapis\.com/graviton\-electric\-symbols/document\_assets/lcsc/2409302330\_XUNPU\-TS\-1088\-AR02016\_C720477\.pdf
- JLCPCB Part Class: Extended Part
- Role Details: Manual boot button pulls GPIO9 low during reset
- Manufacturer Part Number: TS\-1088\-AR02016
- Product Info Url: https://lcsc\.com/product\-detail/Tactile\-Switches\_XUNPU\-TS\-1088\-AR02016\_C720477\.html
- LCSC Part Number: C720477
- Part Type: Tactile Switches
- Package or Case Code: SW\-SMD\_L3\.9\-W3\.0\-P4\.45

**Pins:**
- 1 [pin 1]
- 2 [pin 2]

### U1 — [ESP32\-C3\-WROOM\-02\-N4](https://flux.ai/vasy_skral/esp32-c3-wroom-02-n4~tqi.md)

- Part Type: Module
- Role Details: ESP32\-C3 smart scale controller with integrated PCB antenna
- Manufacturer Part Number: ESP32\-C3\-WROOM\-02\-N4
- Symbol Style: Parametric
- Role: MCU / Wireless Module
- License: https://creativecommons\.org/licenses/by/4\.0/
- Datasheet URL: https://www\.espressif\.com/sites/default/files/documentation/esp32\-c3\-wroom\-02\_datasheet\_en\.pdf
- Manufacturer Name: Espressif Systems

**Pins:**
- 3V3 [pin 1]
- EN [pin 2]
- GND [pin 38]
- GND [pin 32]
- GND [pin 37]
- GND [pin 22]
- GND [pin 19]
- GND [pin 34]
- GND [pin 31]
- GND [pin 21]
- GND [pin 39]
- GND [pin 36]
- GND [pin 9]
- GND [pin 25]
- GND [pin 33]
- GND [pin 29]
- GND [pin 30]
- GND [pin 28]
- GND [pin 20]
- GND [pin 35]
- GND [pin 26]
- GND [pin 24]
- GND [pin 23]
- GND [pin 27]
- IO0 [pin 18]
- IO1 [pin 17]
- IO10 [pin 10]
- IO18 [pin 13]
- IO19 [pin 14]
- IO2 [pin 16]
- IO3 [pin 15]
- IO4 [pin 3]
- IO5 [pin 4]
- IO6 [pin 5]
- IO7 [pin 6]
- IO8 [pin 7]
- IO9 [pin 8]
- RXD [pin 11]
- TXD [pin 12]

### U2 — [HX711](https://flux.ai/kicad-part-library/hx711~na6.md)

- Role Details: Precision bridge ADC for E\+/E\-/A\+/A\- load cell interface
- Package or Case Code: SOP\-16\_3\.9x9\.9mm\_P1\.27mm
- Manufacturer Part Number: HX711
- Role: Load Cell ADC
- Datasheet URL: https://web\.archive\.org/web/20220615044707/https://akizukidenshi\.com/download/ds/avia/hx711\.pdf

**Pins:**
- AGND [pin 5]
- AVDD [pin 3]
- BASE [pin 2]
- DOUT [pin 12]
- DVDD [pin 16]
- INA\- [pin 7]
- INA\+ [pin 8]
- INB\- [pin 9]
- INB\+ [pin 10]
- PD\_SCK [pin 11]
- RATE [pin 15]
- VBG [pin 6]
- VFB [pin 4]
- VSUP [pin 1]
- XI [pin 14]
- XO [pin 13]

### U3 — [BQ24074RGTT](https://flux.ai/lcsc/bq24074rgtt~fpyl.md)

- Datasheet URL: https://www\.ti\.com/lit/ds/symlink/bq24074\.pdf
- Part Type: Battery Management ICs
- JLCPCB Part Class: Extended Part
- Package: VQFN\-16 RGT \(3 mm × 3 mm\) with exposed thermal pad
- Implementation Details: Standalone single\-cell Li\-Ion/Li\-Polymer linear charger and power\-path management IC; 4\.2 V battery regulation, 4\.4 V OUT regulation, 10\.5 V OVP, 1\.5 A programmable fast charge/input current limit\.
- Role: Battery Charger / Power Path
- Role Details: USB 5V LiPo charging and VSYS power\-path management
- LCSC Part Number: C2861252
- Operating Voltage: IN operating range 4\.35–10\.2 V for BQ24074; IN withstand/recommended range up to 26 V, abs max 28 V
- License: https://creativecommons\.org/licenses/by/4\.0/
- Symbol Style: parametric\-v1
- Operating Temperature: \-40 to 85°C
- Manufacturer Part Number: BQ24074RGTT
- Package or Case Code: VQFN\-16\_L3\.0\-W3\.0\-P0\.50\-TL\-EP1\.7
- Manufacturer Name: Texas Instruments

**Pins:**
- \~\{CE\} [pin 4]
- \~\{CHG\} [pin 9]
- \~\{PGOOD\} [pin 7]
- BAT [pin 2]
- BAT [pin 3]
- EN1 [pin 6]
- EN2 [pin 5]
- EP [pin 17]
- ILIM [pin 12]
- IN [pin 13]
- ISET [pin 16]
- ITERM [pin 15]
- OUT [pin 11]
- OUT [pin 10]
- TMR [pin 14]
- TS [pin 1]
- VSS [pin 8]

### U4 — [TPS63031DSKR](https://flux.ai/adrian95/tps63031dskr~yd3.md)

- Manufacturer Name: Texas Instruments
- Role: 3\.3V Buck\-Boost Regulator
- License: https://creativecommons\.org/licenses/by/4\.0/
- Datasheet URL: https://www\.ti\.com/lit/ds/symlink/tps63030\.pdf
- Manufacturer Part Number: TPS63031DSKR
- Role Details: Regulates VSYS to 3\.3V for MCU, HX711, and OLED peripherals
- Part Type: Integrated Circuit

**Pins:**
- EN [pin 6]
- EP [pin 11]
- FB [pin 10]
- GND [pin 9]
- L1 [pin 4]
- L2 [pin 2]
- PGND [pin 3]
- PS/SYNC [pin 7]
- VIN [pin 5]
- VINA [pin 8]
- VOUT [pin 1]

*The full schematic, PCB layout, bill of materials, and interactive design are available at [https://flux\.ai/natarius/smart\-espresso\-scale\-hqhjb\~dbn](https://flux.ai/natarius/smart-espresso-scale-hqhjb~dbn).*

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*Generated from [https://flux\.ai/natarius/smart\-espresso\-scale\-hqhjb\~dbn](https://flux.ai/natarius/smart-espresso-scale-hqhjb~dbn)*