# 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://www.flux.ai/lcsc/smf5p0a~bz6b.md) - Role: ESD Protection - Part Type: TVS - Role Details: 5V TVS clamp for protected USB VBUS - Package or Case Code: SOD-123FL_L2.8-W1.8-LS3.6-RD - Datasheet URL: https://www.lcsc.com/datasheet/C2990427.pdf?spm=wm.sxq.inf.ggs&lcsc_vid=T1kIXgFeT1NaU1RXQFBbUlUHT1cKU1NXFVBeX1VSTlAxVlNRTlBbUVFXRldaXzsOAxUeFF5JWBYZEEoKFBINSQcJGk4dAgUUFAk%3D - JLCPCB Part Class: Extended Part - LCSC Part Number: C2990427 - Max Reverse Voltage: 5V - Forward Voltage: 0.45V to 0.55V (at 1A)V - Manufacturer Part Number: SMF5.0A - Manufacturer Name: Liown(里阳半导体) - Diode Type: Schottky Diode **Pins:** - 1 [pin 1] - 2 [pin 2] ### D2 — [ESD224DQA](https://www.flux.ai/kicad-part-library/esd224dqa~nw.md) - Role: ESD Protection - Manufacturer Name: Texas Instruments Inc. - Role Details: ESD protection for low-level load-cell connector signals; leakage to verify during layout/BOM review - 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 **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://www.flux.ai/adrian95/150060vs55040~c2q.md) - Role Details: Charger STAT indication LED - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Name: Würth Elektronik - Manufacturer Part Number: 150060VS55040 - Part Type: LED - Role: Status LED - Datasheet URL: https://www.we-online.com/components/products/datasheet/150060VS55040.pdf **Pins:** - A [pin 2] - K [pin 1] ### F1 — [SMD050F-2](https://www.flux.ai/adrian95/smd050f-2.md) - Role Details: 500mA hold polyfuse for USB VBUS input - Role: Protection - Mount: Surface Mount - Manufacturer Part Number: SMD050F-2 - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: Circuit Protection Devices - Datasheet URL: https://www.littelfuse.com/assetdocs/littelfuse-ptc-smd-datasheet?assetguid=e664881a-0c68-4836-928b-7ed2f0c2a6da - Manufacturer Name: Littelfuse **Pins:** - ~ [pin 2] - ~ [pin 1] ### J1 — [UJ20-C-H-G-SMT-2-P16-TR](https://www.flux.ai/adrian95/uj20-c-h-g-smt-2-p16-tr~v05.md) - Role: USB-C Power Input - Part Type: Connector - Manufacturer Part Number: UJ20-C-H-G-SMT-2-P16-TR - Role Details: 5V sink-only charge input with CC pull-downs - License: https://creativecommons.org/licenses/by/4.0/ - Datasheet URL: https://www.sameskydevices.com/product/resource/uj20-c-h-g-smt-2-p16-tr.pdf - Mount: Surface Mount - Symbol Style: parametric-v1 - Manufacturer Name: Same Sky (Formerly CUI Devices) **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://www.flux.ai/adrian95/s2b-ph-sm4-tblfsn~b96.md) - Role Details: Protected 1S LiPo pack connection: BAT+ and GND - Manufacturer Part Number: S2B-PH-SM4-TB(LF)(SN) - Role: Battery Connector - Part Type: Connector - Datasheet URL: https://www.jst-mfg.com/product/pdf/eng/ePH.pdf - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Name: JST Sales America Inc. **Pins:** - P1 [pin 1] - P2 [pin 2] ### J3 — [B4B-PH-K-S(LF)(SN)](https://www.flux.ai/lcsc/b4b-ph-k-slfsn~0ffw.md) - Connector Gender: Female - Package or Case Code: CONN-TH_B4B-PH-K-S - Manufacturer Name: JST - Manufacturer Part Number: B4B-PH-K-S(LF)(SN) - Role Details: 4-wire load cell interface: E+, E-, A+, A- - Connector Rows: 1 - 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 - Connector Pitch: 2mm - LCSC Part Number: C131334 - Connector Type: Board to Wire - 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 Positions: 4 - Part Type: Wire To Board / Wire To Wire Connector **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] - 4 [pin 4] ### J4 — [Pin Header 01x04 2.54mm Vertical i2c](https://www.flux.ai/hasanbasri93/pin-header-01x04-2p54mm-vertical-i2c~37.md) - License: https://creativecommons.org/licenses/by/4.0/ - Role: Display Connector - Role Details: I2C OLED header: 3V3, GND, SDA, SCL - Part Type: Connector **Pins:** - 5V [pin 1] - GND [pin 2] - SCL [pin 4] - SDA [pin 3] ### J5 — [AVR-ISP-6](https://www.flux.ai/vasy_skral/avr-isp-6~ry.md) - Manufacturer Part Number: 61200621621 - Exclude from BOM: false - Datasheet URL: https://www.we-online.com/catalog/datasheet/61200621621.pdf - Symbol Style: parametric-v1 - Manufacturer Name: Würth Elektronik - Role: Programming Header - Part Type: Connector - Role Details: ESP32-C3 debug/programming: 3V3, GND, TX, RX, EN, BOOT **Pins:** - GND [pin 6] - MISO [pin 1] - MOSI [pin 4] - RST [pin 5] - SCK [pin 3] - VCC [pin 2] ### SW1 — [TS-1088-AR02016](https://www.flux.ai/lcsc/ts-1088-ar02016~e3n1.md) - LCSC Part Number: C720477 - Manufacturer Name: XUNPU(讯普) - JLCPCB Part Class: Extended Part - Product Info Url: https://lcsc.com/product-detail/Tactile-Switches_XUNPU-TS-1088-AR02016_C720477.html - Package or Case Code: SW-SMD_L3.9-W3.0-P4.45 - Manufacturer Part Number: TS-1088-AR02016 - Role Details: Tare/user zero button to ESP32 GPIO - Part Type: Tactile Switches - Role: Button - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2409302330_XUNPU-TS-1088-AR02016_C720477.pdf **Pins:** - 1 [pin 1] - 2 [pin 2] ### SW2 — [TS-1088-AR02016](https://www.flux.ai/lcsc/ts-1088-ar02016~e3n1.md) - Manufacturer Name: XUNPU(讯普) - LCSC Part Number: C720477 - Role: Button - Role Details: Mode/timer control button to ESP32 GPIO - JLCPCB Part Class: Extended Part - Manufacturer Part Number: TS-1088-AR02016 - Part Type: Tactile Switches - Package or Case Code: SW-SMD_L3.9-W3.0-P4.45 - Product Info Url: https://lcsc.com/product-detail/Tactile-Switches_XUNPU-TS-1088-AR02016_C720477.html - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2409302330_XUNPU-TS-1088-AR02016_C720477.pdf **Pins:** - 1 [pin 1] - 2 [pin 2] ### SW3 — [Slide Switch SW_SPDT](https://www.flux.ai/404src/slide-switch-swspdt~nq.md) - Datasheet URL: https://www.taydaelectronics.com/datasheets/A-5111.pdf - Purchase Url: https://www.taydaelectronics.com/slide-switch-1p2t-through-hole-0-5a-50vdc.html - Manufacturer Name: Wealth Metal - Role Details: Manual system power switch; 0.5A rated, adequate for estimated scale load but review if adding higher-current loads - Manufacturer Part Number: SS12F44G5 - Role: Power Switch **Pins:** - A [pin 1] - B [pin 2] - C [pin 3] ### SW4 — [TS-1088-AR02016](https://www.flux.ai/lcsc/ts-1088-ar02016~e3n1.md) - LCSC Part Number: C720477 - Manufacturer Name: XUNPU(讯普) - JLCPCB Part Class: Extended Part - Package or Case Code: SW-SMD_L3.9-W3.0-P4.45 - Product Info Url: https://lcsc.com/product-detail/Tactile-Switches_XUNPU-TS-1088-AR02016_C720477.html - Role Details: Manual reset button pulls ESP32 EN low - Manufacturer Part Number: TS-1088-AR02016 - Part Type: Tactile Switches - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2409302330_XUNPU-TS-1088-AR02016_C720477.pdf - Role: Switching **Pins:** - 1 [pin 1] - 2 [pin 2] ### SW5 — [TS-1088-AR02016](https://www.flux.ai/lcsc/ts-1088-ar02016~e3n1.md) - Manufacturer Part Number: TS-1088-AR02016 - Part Type: Tactile Switches - Product Info Url: https://lcsc.com/product-detail/Tactile-Switches_XUNPU-TS-1088-AR02016_C720477.html - Package or Case Code: SW-SMD_L3.9-W3.0-P4.45 - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2409302330_XUNPU-TS-1088-AR02016_C720477.pdf - Manufacturer Name: XUNPU(讯普) - LCSC Part Number: C720477 - Role Details: Manual boot button pulls GPIO9 low during reset - Role: Switching - JLCPCB Part Class: Extended Part **Pins:** - 1 [pin 1] - 2 [pin 2] ### U1 — [ESP32-C3-WROOM-02-N4](https://www.flux.ai/vasy_skral/esp32-c3-wroom-02-n4~tqi.md) - Role: MCU / Wireless Module - Datasheet URL: https://www.espressif.com/sites/default/files/documentation/esp32-c3-wroom-02_datasheet_en.pdf - Symbol Style: Parametric - Role Details: ESP32-C3 smart scale controller with integrated PCB antenna - Part Type: Module - Manufacturer Part Number: ESP32-C3-WROOM-02-N4 - License: https://creativecommons.org/licenses/by/4.0/ - 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://www.flux.ai/kicad-part-library/hx711~na6.md) - Package or Case Code: SOP-16_3.9x9.9mm_P1.27mm - Role Details: Precision bridge ADC for E+/E-/A+/A- load cell interface - Role: Load Cell ADC - Datasheet URL: https://web.archive.org/web/20220615044707/https://akizukidenshi.com/download/ds/avia/hx711.pdf - Manufacturer Part Number: HX711 **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://www.flux.ai/lcsc/bq24074rgtt~fpyl.md) - Datasheet URL: https://www.ti.com/lit/ds/symlink/bq24074.pdf - Role Details: USB 5V LiPo charging and VSYS power-path management - Manufacturer Name: Texas Instruments - Operating Voltage: IN operating range 4.35–10.2 V for BQ24074; IN withstand/recommended range up to 26 V, abs max 28 V - Operating Temperature: -40 to 85°C - Package or Case Code: VQFN-16_L3.0-W3.0-P0.50-TL-EP1.7 - JLCPCB Part Class: Extended Part - Symbol Style: parametric-v1 - Role: Battery Charger / Power Path - LCSC Part Number: C2861252 - License: https://creativecommons.org/licenses/by/4.0/ - 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. - Package: VQFN-16 RGT (3 mm × 3 mm) with exposed thermal pad - Part Type: Battery Management ICs - Manufacturer Part Number: BQ24074RGTT **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://www.flux.ai/adrian95/tps63031dskr~yd3.md) - Manufacturer Part Number: TPS63031DSKR - Datasheet URL: https://www.ti.com/lit/ds/symlink/tps63030.pdf - Part Type: Integrated Circuit - License: https://creativecommons.org/licenses/by/4.0/ - Role: 3.3V Buck-Boost Regulator - Role Details: Regulates VSYS to 3.3V for MCU, HX711, and OLED peripherals - Manufacturer Name: Texas Instruments **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://www.flux.ai/natarius/smart-espresso-scale-hqhjb~dbn](https://www.flux.ai/natarius/smart-espresso-scale-hqhjb~dbn).* --- *Generated from [https://www.flux.ai/natarius/smart-espresso-scale-hqhjb~dbn](https://www.flux.ai/natarius/smart-espresso-scale-hqhjb~dbn)*