4 layers136.5 × 70 mm
4 layers100 × 50 mm
Chronolog
slemanz/chronolog5STM32-based temperature data logger with RTC, NOR flash storage, LCD and Wi-Fi. Hardware and firmware.
- Size
- 100 × 50 mm
- Copper layers
- 4
- Thickness
- 1.61 mm
- Parts
- 95
- Nets
- 82
- Pads
- 308
- Tracks, vias
- 805, 325
- Pours
- 11
- Routed
- Yes
- KiCad
- KiCad 9.0 (file 20241229)
- Created
- 1 Sep 2026
- Updated
- 17 Oct 2026
Overview
Chronolog is an open-source printed circuit board by slemanz, from the slemanz/chronolog repository on GitHub. It is a 4-layer board of 100 × 50 mm with 95 parts on 82 nets, routed with 805 tracks and 325 vias.
It is built around the STM32F072CBT6, ESP-01 and LM75BD, with the PCF8574T, W25Q32JVSNIQ and AP2114H-3.3TRG1 among its other parts. Its parts include 31 capacitors, 26 resistors, 9 ICs, 7 diodes and 4 connectors. It belongs with the radio and wireless and sensors and measurement boards and the ESP8266 and STM32 boards of this library.
Main components
12
STM32F072CBT6
LQFP-48(7x7)-40℃~+85℃ 1.65V~3.6V 128KB 12bit 12bit 16KB 32 Bit 37 48MHz ARM Cortex-M0 Built-in FLASH LQFP-48(7x7) Microcontrollers (MCU/MPU/SOC) ROHSSTMicroelectronicsMicrocontrollers (MCU/MPU/SOC)
ESP-01
插件-20℃~+85℃ -90dBm 16dBm 2.4GHz 20mA 300mA 3V~3.6V 802.11b/g/n ESP8266 Chip Over-the-air (OTA) update UART 插件 WiFi Modules ROHSAi-ThinkerWiFi Modules
LM75BD
SOIC-8-55℃~+125℃ 10ms 11bit 1uA 2.8V~5.5V I2C ±2℃ SOIC-8 Temperature Sensors ROHSNXP SemiconductorsTemperature Sensors
PCF8574T
SOP-16-300mil-40℃~+85℃ 100kHz 10uA 2.5V~6V 25mA 300uA 8 8 Cascading and address extension、Built-in LED driver I2C Interrupt Output Open-drain SOP-16-300mil I/O Expanders ROHSHGSEMII/O ExpandersW25Q32JVSNIQ
SOIC-8-150mil-40℃~+85℃ 100,000 cycles 10uA 133MHz 150ms@(64KB) 2.7V~3.6V 20 Years 32Mbit 3ms SPI SOIC-8-150mil NOR FLASH ROHSWinbond ElecNOR FLASH
AP2114H-3.3TRG1
SOT-223-40℃~+85℃@(Ta) 1 1A 3.3V 30uVrms 450mV@(1A) 65dB@(1kHz) 65uA 6V Fixed Over Current Protection、Over Temperature Protection Positive SOT-223 Voltage Regulators - Linear, Low Drop Out (LDO) Regulators ROHSDiodes IncorporatedVoltage Regulators - Linear, Low Drop Out (LDO) Regulators
USBLC6-2SC6
SOT-23-60.35pF、0.8pF 100nA 150W@8/20us 15V 2 5V 6A@8/20us 6V ESD SOT-23-6 ESD and Surge Protection (TVS/ESD) ROHSUMWESD And Surge Protection (TVS/ESD)
CC0603KRX7R9BB104
0603100nF 50V X7R ±10% 0603 Multilayer Ceramic Capacitors MLCC - SMD/SMT ROHSYAGEOMultilayer Ceramic Capacitors MLCC - SMD/SMT
TS-1088-AR02016
SMD,4x3mm-30℃~+80℃ 1.6N 100,000 cycles 12V 2mm 3.9mm 3mm 50mA Black Round Button SMD(SMT) Tab SPST Surface Mount,Vertical Without Bracket SMD,4x3mm Tactile Switches ROHSXUNPUTactile Switches
CL32B226KAJNNNE
121022uF 25V X7R ±10% 1210 Multilayer Ceramic Capacitors MLCC - SMD/SMT ROHSSamsung Electro-MechanicsMultilayer Ceramic Capacitors MLCC - SMD/SMT
BSS138
SOT-23-55℃~+150℃ 1 N-channel 1.1Ω@10V、1.2Ω@4.5V 1.2V 1.7nC@10V 17.5pF 340mA 350mW 50V 6.5pF N-Channel SOT-23 MOSFETs ROHShongjiachengMOSFETs
KT-0603R
0603-40℃~+85℃ 1.6mm x 0.8mm square LED 1.8V~2.4V 120° 20mA 300mcd 40mW 615nm~630nm 645nm Discrete Diode Red Water Clear 0603 LED Indication - Discrete ROHSHubei KENTO ElecLED Indication - Discrete
README
README.mdChronolog
Overview
Chronolog is a temperature data logger built end to end, covering both hardware and firmware. It records timestamped temperature readings to external flash and shows live data on an LCD and over Wi-Fi.
Repository Structure
- 🔌 hardware: KiCad project with schematic, PCB layout and production files.
- 💾 Firmware: coming soon
Parts
95| Qty | Value | Footprint | References |
|---|---|---|---|
| 19 | 100nF | 02_capacitors:C_0603_1608Metric | C3, C4, C10, C14, C15, C17, C18, C20, C23, C24, C25, C26, C27, C28, C30, C31 +3 |
| 10 | 10k | 01_resistors:R_0603_1608Metric | R1, R2, R12, R13, R14, R15, R18, R19, R20, R21 |
| 5 | 4k7 | 01_resistors:R_0603_1608Metric | R4, R16, R17, R22, R25 |
| 4 | M4-4.3D-8.6P | 12_mechanical:MountingHole_4.3mm_M4_Pad | H1, H2, H3, H4 |
| 4 | TS-1088-AR02016 | 09_electromechanical:SW_SPST_TS-1088-xR020 | S1, S2, S3, S4 |
| 2 | 10uF | 02_capacitors:C_0805_2012Metric | C16, C29 |
| 2 | 18pF | 02_capacitors:C_0603_1608Metric | C21, C22 |
| 2 | 1k | 01_resistors:R_0603_1608Metric | R5, R23 |
| 2 | 22uF | 02_capacitors:C_1210_3225Metric | C5, C6 |
| 2 | 47R | 01_resistors:R_0603_1608Metric | R8, R9 |
| 2 | BSS138 | 05_transistors:SOT-23 | Q1, Q2 |
| 2 | KT-0603R | 04_diodes:LED_0603_1608Metric | D3, D4 |
| 1 | 0R | 01_resistors:R_0603_1608Metric | R3 |
| 1 | 1.0P-SMD | 12_mechanical:TestPoint_Pad_D1.0mm | TP1 |
| 1 | 100k | 01_resistors:R_0603_1608Metric | R10 |
| 1 | 10k | 01_resistors:TH_3362P | R24 |
| 1 | 10nF | 02_capacitors:C_0603_1608Metric | C13 |
| 1 | 10uF | 02_capacitors:C_1210_3225Metric | C2 |
| 1 | 12R | 01_resistors:R_0805_2012Metric | R26 |
| 1 | 1uF | 02_capacitors:C_0603_1608Metric | C12 |
| 1 | 220R | 01_resistors:R_0603_1608Metric | R7 |
| 1 | 22k | 01_resistors:R_0603_1608Metric | R11 |
| 1 | 22uF | 02_capacitors:C_0805_2012Metric | C19 |
| 1 | 32.768kHz | 07_crystals:Crystal_SMD_3215-2Pin_3.2x1.5mm | Y1 |
| 1 | 4.7uF | 02_capacitors:C_0603_1608Metric | C11 |
| 1 | 4.7uH | 03_inductors:L_1008_2520Metric | L1 |
| 1 | 470R | 01_resistors:R_0603_1608Metric | R6 |
| 1 | 47uF | 02_capacitors:CP_Elec_6.3x5.8 | C1 |
| 1 | AP2114H-3.3TRG1 | 06_ics:SOT-223-3_TabPin2 | U3 |
| 1 | AP63205WU-7 | 06_ics:TSOT-23-6 | U1 |
| 1 | B-2100S04P-A110 | 08_connectors:PinHeader_1x04_P2.54mm_Vertical | J3 |
| 1 | B340AE-13 | 04_diodes:D_SMA | D1 |
| 1 | B4B-XH-A | 08_connectors:JST_XH_B4B-XH-A_1x04_P2.50mm_Vertical | J2 |
| 1 | B5819W-TP | 04_diodes:D_SOD-123 | D6 |
| 1 | BAT54C | 04_diodes:SOT-23 | D7 |
| 1 | BC817-40LT1G | 05_transistors:SOT-23 | Q3 |
| 1 | BS-08-B2AA001 | 09_electromechanical:SMD_BS-08-B2AA001 | BT1 |
| 1 | DC-005-5A-2.0 | 08_connectors:TH_DC-005-5A-2.0 | J1 |
| 1 | ESP-01 | 11_modules:ESP-01 | U7 |
| 1 | LM75BD | 06_ics:SOIC-8_3.9x4.9mm_P1.27mm | U6 |
| 1 | PCF8574T | 06_ics:SOIC-16W_7.5x10.3mm_P1.27mm | U9 |
| 1 | SMAJ33A | 04_diodes:D_SMA | D2 |
| 1 | STM32F072CBT6 | 06_ics:LQFP-48_7x7mm_P0.5mm | U2 |
| 1 | U254-051N-4BH806 | 08_connectors:SMD_U254-051N-4BH806 | J4 |
| 1 | USBLC6-2SC6 | 06_ics:SOT-23-6 | U4 |
| 1 | W25Q32JVSNIQ | 06_ics:SOIC-8_3.9x4.9mm_P1.27mm | U5 |
| 1 | WC1602A | 11_modules:WC1602A | U8 |
| 1 | XL-5050RGBC | 04_diodes:PLCC-6_XL-5050RGBC | D5 |
The 92 most common of 95 parts.
Questions
How big is the Chronolog PCB?
It measures 100 × 50 mm and has 4 copper layers, 1.61 mm thick.
What parts does the Chronolog use?
95 parts, built around the STM32F072CBT6, ESP-01, LM75BD and PCF8574T. 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 Chronolog KiCad files?
From the slemanz/chronolog repository on GitHub, at the commit this page was made from: the board is hardware/chronolog.kicad_pcb and its schematic hardware/chronolog.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Chronolog design in my own project?
Its repository states no licence, so its author keeps all rights: ask slemanz before reusing the design.
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