LaskaKit Meteo Mini is a Czech board for battery-powered weather stations with the ESP32-C3 chip. Sensors connect by cable to μŠup connectors (compatible with Qwiic and STEMMA QT) without soldering, and the board charges a Li-Ion cell from USB-C as well as from a solar panel.
The sensor power can be switched off separately, so the board lasts a long time on battery in deep sleep.
Specifications
- ESP32-C3 (ESP32-C3-MINI-1-N4 module): RISC-V up to 160 MHz, 4 MB flash
- 2.4 GHz Wi-Fi, Bluetooth LE 5
- μŠup I2C, μŠup SPI and 2× μŠup IO (GPIO1, GPIO10 for DS18B20)
- BQ24074 charger: USB-C 3.4–5.5 V and solar panel 5–10 V, JST-PH connectors for the cell and the panel
- switchable VSENSOR sensor power (GPIO4), battery voltage measurement (GPIO0)
- USB-C via a CH9102F converter, SK6812 RGB LED, button, power switch
- 49.5 × 33 mm
The pinout applies to version 4.1 and is based on LaskaKit documentation (schematic, Gerbers). The diagram shows the component side rotated 90° relative to the manufacturing files – μŠup I2C and SPI on the right, μŠup IO on the left, USB-C on the left, antenna at the bottom. The numbers next to the labels are connector pins; pin 1 is always GND.
All μŠup connectors are powered from VSENSOR. Turn it on before talking to the sensors: digitalWrite(4, HIGH), and turn it off again before sleep. The battery voltage is the voltage on GPIO0 × 1.769.
Pinout and pin table
Hover over a pin in the diagram or a table row; use the filter to highlight a bus. You can download the pinout as PNG or SVG.
| Pin | Name | Direction | UART | I2C | SPI | ADC | Note |
|---|---|---|---|---|---|---|---|
| μŠup I2C 1 | GND | – | |||||
| μŠup I2C 2 | VSENSOR | output | Power for all μŠup connectors and the RGB LED from a dedicated regulator. Enabled by GPIO4 (logic 1); without it the sensors don't work. While it is off, don't drive I2C and IO to logic 1 – the sensors would be powered through the data lines. | ||||
| μŠup I2C 3 | GPIO19 | input/output | SDA | I2C SDA. 4k7 pull-ups to VSENSOR are connected only by the I2C_PULL-UP jumper on the bottom (open from the factory) – sensors with their own pull-ups (μŠup modules) work without it. | |||
| μŠup I2C 4 | GPIO18 | input/output | SCL | I2C SCL; for pull-ups see SDA. On the chip this is USB D−, but USB-C goes through the CH9102F converter. | |||
| μŠup SPI 1 | GND | – | |||||
| μŠup SPI 2 | VSENSOR | output | Power for all μŠup connectors and the RGB LED from a dedicated regulator. Enabled by GPIO4 (logic 1); without it the sensors don't work. While it is off, don't drive I2C and IO to logic 1 – the sensors would be powered through the data lines. | ||||
| μŠup SPI 3 | GPIO2 | input/output | MISO | ADC1_CH2 | SPI MISO. Strapping pin: a sensor that pulls MISO to logic 0 at boot will block startup. | ||
| μŠup SPI 4 | GPIO6 | input/output | SCK | JTAG MTCK | |||
| μŠup SPI 5 | GPIO7 | input/output | MOSI | JTAG MTDO | |||
| μŠup SPI 6 | GPIO3 | input/output | SS | ADC1_CH3 | |||
| μŠup IO1 1 | GND | – | |||||
| μŠup IO1 2 | VSENSOR | output | Power for all μŠup connectors and the RGB LED from a dedicated regulator. Enabled by GPIO4 (logic 1); without it the sensors don't work. While it is off, don't drive I2C and IO to logic 1 – the sensors would be powered through the data lines. | ||||
| μŠup IO1 3 | GPIO1 | input/output | ADC1_CH1 | Free I/O on the μŠup IO connector, no pull-up; can also be used as an analog input (ADC1_CH1). | |||
| μŠup IO10 (DS18B20) 1 | GND | – | |||||
| μŠup IO10 (DS18B20) 2 | VSENSOR | output | Power for all μŠup connectors and the RGB LED from a dedicated regulator. Enabled by GPIO4 (logic 1); without it the sensors don't work. While it is off, don't drive I2C and IO to logic 1 – the sensors would be powered through the data lines. | ||||
| μŠup IO10 (DS18B20) 3 | GPIO10 | input/output | 1-Wire for DS18B20: 4k7 pull-up to VSENSOR after closing JP1 (open from the factory). | ||||
| Battery 1 | BAT+ | input/output | 3.7 V Li-Ion / Li-Pol cell (charged by BQ24074) | ||||
| Battery 2 | GND | – | |||||
| Solar panel 1 | SOLAR | input | Solar panel 5–10 V (6 V recommended) | ||||
| Solar panel 2 | GND | – |
Pins used on the board
These chip pins are used by parts on the board and are not broken out:
| Pin | Function on the board |
|---|---|
| GPIO0 | Battery voltage via 1 MΩ / 1.3 MΩ divider (Vbat = Vadc × 1.769); ADC jumper underneath |
| GPIO4 | Sensor power enable VSENSOR (logic 1 = on) |
| GPIO5 | Button on the left side (10k pull-up, pressed = logic 0) |
| GPIO8 | 10k pull-up only (strapping pin), not routed anywhere else |
| GPIO9 | SK6812 RGB LED and auto-download circuit – strapping pin, must not be logic 0 at boot |
| GPIO20, 21 | UART0 to the CH9102F converter (USB-C) |
What to watch out for
- The GPIO are not 5V tolerant.
- Sensors on μŠup won’t work until GPIO4 turns on the VSENSOR power.
- The onboard I2C pull-ups are connected only with the I2C_PULL-UP solder jumper on the bottom – μŠup modules have their own.
- GPIO2 (MISO on μŠup SPI) and GPIO9 (RGB LED) are strapping pins – they must not be at logic 0 at boot.
- The board has no BOOT button – the CH9102F converter handles uploading on its own.
- Version 3.5 switched the sensor power via GPIO3, version 4.x via GPIO4.
More pinouts
See all pinouts on the Pinouts page.