Coffee scale
About the Coffee scale PCB
Coffee scale is an open source STM32 PCB design by lucasnoce, published on GitHub under the MIT license. It is a 2-layer board measuring 60 × 35 mm, with 66 components from 34 distinct parts.
Its main chip is the STM32F103C8Tx, from the STM32 family. Other key parts include the TLV61046ADB, HX711, DW01A and TP4056-42-ESOP8. By type, the board carries 23 capacitors, 22 resistors, 5 ICs, 5 switches, 4 connectors and 3 transistors.
From the project
Weight measuring device, targeted for coffee making
Main components on the Coffee scale
Coffee scale bill of materials (BOM)
66 components, 34 distinct parts.
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 1 | TLV61046ADB | SOT-23-6 | U1 |
| 1 | STM32F103C8Tx | LQFP-48_7x7mm_P0.5mm | U2 |
| 1 | HX711 | SOIC-16_3.9x9.9mm_P1.27mm | U3 |
| 1 | DW01A | SOT-23-6 | U4 |
| 1 | TP4056-42-ESOP8 | SOIC-8-1EP_3.9x4.9mm_P1.27mm_EP2.41x3.3mm_ThermalVias | U5 |
| 1 | AO3401A | SOT-23 | Q1 |
| 1 | PNP | SOT-23 | Q3 |
| 1 | Q_Dual_NMOS_S1G1D2S2G2D1 | SOT-363_SC-70-6 | Q4 |
| 1 | BAT_IN | Terminal_Pad_01x02-3x5mm | J1 |
| 1 | OLED | Terminal_Pad_01x04-2x3mm | J2 |
| 1 | LOAD_CELL | Terminal_Pad_01x04-2x3mm | J3 |
| 1 | USB_C_Receptacle_PowerOnly_24P | USB_C_Receptacle_GCT_USB4125-xx-x_6P_TopMnt_Horizontal | J5 |
| 1 | 10SPS | SolderJumper-2_P1.3mm_Bridged_RoundedPad1.0x1.5mm | JP1 |
| 1 | SW_PWR | Sliding_Switch_MK-12C02-G020 | SW1 |
| 1 | SW_BACK | SW_TS-1187A-B-A-B | SW2 |
| 1 | SW_L | SW_TS-1187A-B-A-B | SW3 |
| 1 | SW_R | SW_TS-1187A-B-A-B | SW4 |
| 1 | SW_OK | SW_TS-1187A-B-A-B | SW5 |
| 1 | LED_CHRG | LED_0805_2012Metric | D1 |
| 1 | L_Small | L_6.3x6.3_H3 | L1 |
Show 14 more
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 1 | 3.3uH | L_0805_2012Metric | L2 |
| 14 | 100n | C_0805_2012Metric | C1, C2, C3, C4, C11, C12, C14, C15 +6 |
| 4 | 10n | C_0805_2012Metric | C5, C7, C9, C10 |
| 1 | ? | C_0805_2012Metric | C6 |
| 1 | C_Small | C_0805_2012Metric | C8 |
| 3 | 10u | C_0805_2012Metric | C13, C18, C20 |
| 7 | 10k | R_0805_2012Metric | R1, R3, R7, R9, R11, R12, R13 |
| 6 | 1k | R_0805_2012Metric | R2, R4, R8, R10, R22, R23 |
| 2 | R_Small | R_0805_2012Metric | R5, R6 |
| 1 | 8k2 | R_0805_2012Metric | R16 |
| 1 | 20k | R_0805_2012Metric | R17 |
| 3 | 100R | R_0805_2012Metric | R18, R19, R21 |
| 1 | 100k | R_0805_2012Metric | R20 |
| 1 | 1k2 | R_0805_2012Metric | R24 |
Coffee scale design files
The KiCad project lives in the lucasnoce/coffee-scale repository on GitHub; these links point at the commit this page was built from.
Coffee scale: common questions
What microcontroller does the Coffee scale use?
The Coffee scale is built around the STM32F103C8Tx, from the STM32 family.
How big is the Coffee scale PCB?
The Coffee scale measures 60 × 35 mm, has 2 copper layers and is 1.6 mm thick.
How many components are on the Coffee scale?
66 components, from 34 distinct parts. The full bill of materials is listed on this page.
Where can I download the Coffee scale design files?
From the lucasnoce/coffee-scale repository on GitHub, which has the KiCad layout and the schematic; the links under Design files point to each one.
Can I use the Coffee scale design in my own project?
Yes, under the terms of its MIT license, which lucasnoce chose for the repository.
Can I test firmware for the Coffee scale without the hardware?
Yes. HardLabs builds a simulation of the board from its netlist and BOM, so you can run and debug STM32 firmware against it before you order a PCB.
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