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.
Similar boards
- 2 layers56 × 70 mm
CFS Bus Adapter R2
fake-name/cfs-reverse-engineering
Reverse engineering the Creality CFS for use as a general AMU/MMU system
66 parts58 - 4 layers25 × 55 mm
- 4 layers100 × 100 mm
- 4 layers267 × 75 mm
Fracture
SharKingStudios/Fracture
An infinitely expandable, velocity sensing split midi keyboard.
208 parts10MIT - 4 layers74 × 36.3 mm
Loudcardsdevice
gelotek-com/Anki-In-Hardware
Building a physical flashcard device inspired by Anki and spaced repetition.
87 parts2 - 2 layers99 × 90 mm
- 4 layers72 × 51.1 mm
Esp32s3-audio streamer
wemaxon/esp32-audio-streamer
Hardware design for a WiFi/Bluetooth audio streamer using the esp32 microcontroller and the PCM5102A DAC, intended to be used with squeezelite firmware.
63 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.