2 layers96 × 74 mm
MacroController
alex1klimovich/nrf52840-macro-controller
Custom nRF52840 productivity controller for digital artists — PCB, BLE/USB firmware, OLED, haptics, RGB, and enclosure CAD.
78 parts1
2 layers65.1 × 30.3 mm
Desk timer
nshcat/desk_timer[ ] For some reason, I needed to add "-isystem /usr/arm-none-eabi/include/c++/14.2.0" to the compilecommands.json entry for main.cxx in order for clangd to find the system includes.
- Size
- 65.1 × 30.3 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 35
- Nets
- 77
- Pads
- 179
- Tracks, vias
- 418, 43
- Pours
- 2
- Routed
- Yes
- KiCad
- KiCad 9.0 (file 20241229)
- Created
- 19 Jun 2025
- Updated
- 3 Aug 2025
Overview
Desk timer is an open-source printed circuit board by nshcat, from the nshcat/desk_timer repository on GitHub. It is a 2-layer board of 65.1 × 30.3 mm with 35 parts on 77 nets, routed with 418 tracks and 43 vias.
It is built around the STM32G0B1CBT6, AMS1117-3.3 and BLM21PG221SN1D, with the GT-USB-7010ASV and PKMCS0909E4000-R1 among its other parts. Its parts include 10 capacitors, 7 resistors, 3 connectors, 2 ICs and 2 diodes. It belongs with the STM32 boards of this library.
Main components
5
STM32G0B1CBT6
LQFP-48(7x7)-40℃~+85℃ 1.7V~3.6V 128KB 144KB 32 Bit 44 64MHz ARM Cortex-M0+ Built-in+External FLASH LQFP-48(7x7) Microcontrollers (MCU/MPU/SOC) ROHSSTMicroelectronicsMicrocontrollers (MCU/MPU/SOC)
AMS1117-3.3
SOT-223-40℃~+125℃ 0.003%Vout 1 1.1V@(800mA) 15V 1A 3.3V 5mA 72dB@(120Hz) Fixed Over Current Protection、Short Circuit Protection、Thermal shutdown Positive SOT-223 Voltage Regulators - Linear, Low Drop Out (LDO) Regulators ROHSAdvanced Monolithic SystemsVoltage Regulators - Linear, Low Drop Out (LDO) Regulators
BLM21PG221SN1D
08051 220Ω@100MHz 2A 45mΩ ±25% 0805 Ferrite Beads ROHSMurataFerrite Beads
GT-USB-7010ASV
SMD-40℃~+85℃ 1 1.68mm 10,000 Cycles 16P 24V 3A 7.35mm Black Female Surface Mount, Right Angle Type-C USB 2.0 SMD USB Connectors ROHSG-SwitchUSB Connectors
PKMCS0909E4000-R1
SMD,9x9mm-40℃~+85℃ 1.9mm 12.5V 4kHz 65dB 9mm 9mm Passive (Externally Driven) Piezoelectric SMD,9x9mm Buzzers ROHSMurataBuzzers
README
README.mddesk_timer
TODOs
[ ] For some reason, I needed to add "-isystem /usr/arm-none-eabi/include/c++/14.2.0" to the compile_commands.json entry for main.cxx in order for clangd to find the system includes.
[ ] Compiling and linking u8g2 as a static library does not seem to work - the final desk_timer.elf binary is way too large (multiple megabytes big), and while having LTO enabled via the CMake LTO settings shrinks the binary again, it doesnt work on the MCU. I did have to use -ffunction-sections and -fdata-sections, maybe that messed up the final .bin flash image generation, because it creates individual sections for each function and data symbol?
Parts
35| Qty | Value | Footprint | References |
|---|---|---|---|
| 4 | 5K1 | Resistor_SMD:R_0402_1005Metric | R1, R2, R4, R5 |
| 3 | 100nF | Capacitor_SMD:C_0805_2012Metric | C7, C8, C10 |
| 2 | 10pF | Capacitor_SMD:C_0402_1005Metric | C3, C4 |
| 2 | 12pF | Capacitor_SMD:C_0402_1005Metric | C5, C6 |
| 2 | 22uF | Capacitor_SMD:C_1206_3216Metric | C1, C2 |
| 1 | 10k | Resistor_SMD:R_0402_1005Metric | R3 |
| 1 | 10nF | Capacitor_SMD:C_0805_2012Metric | C9 |
| 1 | 1K | Resistor_SMD:R_0402_1005Metric | R9 |
| 1 | 2SC4213 | Package_TO_SOT_SMD:SOT-323_SC-70 | Q1 |
| 1 | 300R | Resistor_SMD:R_1206_3216Metric_Pad1.30x1.75mm_HandSolder | R8 |
| 1 | 32.768 KHz, 10ppm, 12.5pf | Crystal:Crystal_SMD_3215-2Pin_3.2x1.5mm | Y1 |
| 1 | 8 MHz, 10ppm, 10pf | Crystal:Crystal_SMD_3225-4Pin_3.2x2.5mm | Y2 |
| 1 | AMS1117-3.3 | Package_TO_SOT_SMD:SOT-223-3_TabPin2 | U2 |
| 1 | BLM21PG221SN1D | Inductor_SMD:L_0805_2012Metric | FB1 |
| 1 | GT-USB-7010ASV | Connector_USB:USB_C_Receptacle_G-Switch_GT-USB-7010ASV | J1 |
| 1 | PKMCS0909E4000-R1 | Buzzer_Beeper:Buzzer_Murata_PKMCS0909E | BZ1 |
| 1 | Pin Headers,2x20,SMD,P2.54mm,vertical | Connector_PinHeader_2.54mm:PinHeader_2x20_P2.54mm_Vertical | J2 |
| 1 | RED | LED_SMD:LED_0402_1005Metric | D2 |
| 1 | STM32G0B1CBT6 | Package_QFP:LQFP-48_7x7mm_P0.5mm | U1 |
| 1 | SWD | Connector_PinHeader_2.54mm:PinHeader_1x07_P2.54mm_Horizontal | J3 |
| 1 | SW_Push | Button_Switch_SMD:SW_SPST_B3U-1000P | SW1 |
| 1 | TestPoint_Pad_1.0x1.0mm | TestPoint:TestPoint_Pad_1.0x1.0mm | 3V3 |
| 1 | YELLOW GREEN | LED_SMD:LED_0402_1005Metric | D1 |
The 31 most common of 35 parts.
Questions
How big is the Desk timer PCB?
It measures 65.1 × 30.3 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Desk timer use?
35 parts, built around the STM32G0B1CBT6, AMS1117-3.3, BLM21PG221SN1D and GT-USB-7010ASV. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the Desk timer KiCad files?
From the nshcat/desk_timer repository on GitHub, at the commit this page was made from: the board is hardware/desk_timer.kicad_pcb and its schematic hardware/connectivity.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Desk timer design in my own project?
Its repository states no licence, so its author keeps all rights: ask nshcat before reusing the design.
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