WEMOS LOLIN32 Lite
Compact ESP32 board with Wi-Fi, BLE, and built-in LiPo charging - ideal for portable, battery-powered IoT projects.
Pinout
26 pins · 2.54 mm pitch
| Pin | GPIO | Labels | Status | Capabilities | Notes |
|---|---|---|---|---|---|
| 1 | - | 5V | power | - | 5V power input for the board |
| 2 | - | GND | ground | - | Ground connection |
| 3 | - | 3V33.3V | power | - | 3.3V power output |
| 4 | 0 | IO0GPIO0 | strapping | adc | GPIO, ADC |
| 5 | 2 | IO2GPIO2 | strapping | adc | GPIO, ADC |
| 6 | 4 | IO4GPIO4 | strapping | adc | GPIO, ADC |
| 7 | 5 | IO5GPIO5 | strapping | - | GPIO |
| 8 | 12 | IO12GPIO12 | strapping | adc | GPIO, ADC |
| 9 | 13 | IO13GPIO13 | strapping | adc | GPIO, ADC |
| 10 | 14 | IO14GPIO14 | strapping | adc | GPIO, ADC |
| 11 | 15 | IO15GPIO15 | strapping | - | GPIO |
| 12 | 16 | IO16GPIO16 | strapping | - | GPIO |
| 13 | 17 | IO17GPIO17 | strapping | - | GPIO |
| 14 | 18 | IO18GPIO18 | safe | - | GPIO |
| 15 | 19 | IO19GPIO19 | safe | - | GPIO |
| 16 | 22 | IO22GPIO22 | safe | - | GPIO |
| 17 | 23 | IO23GPIO23 | safe | - | GPIO |
| 18 | 25 | IO25GPIO25 | safe | adc | GPIO, ADC |
| 19 | 26 | IO26GPIO26 | safe | adc | GPIO, ADC |
| 20 | 27 | IO27GPIO27 | safe | adc | GPIO, ADC |
| 21 | 32 | IO32GPIO32 | safe | adc | GPIO, ADC |
| 22 | 33 | IO33GPIO33 | safe | adc | GPIO, ADC |
| 23 | 34 | IO34GPIO34 | strapping | adc | GPIO, ADC |
| 24 | 35 | IO35GPIO35 | strapping | adc | GPIO, ADC |
| 25 | 36 | IO36GPIO36 | strapping | adc | GPIO, ADC |
| 26 | 39 | IO39GPIO39 | strapping | adc | GPIO, ADC |
Start with these
9 pins with no boot or system involvementFreely assignable - no strapping, flash, USB or JTAG duties. Ideal first picks for buttons, sensors and LEDs.
Fine - with a little care
sampled at boot or shared with debug/serial| Pin | Label | What to know | Role |
|---|---|---|---|
| IO0 | GPIO0 | Must be HIGH during boot for normal startup; if held LOW on reset, forces flash programming mode. | Strapping |
| IO2 | GPIO2 | If driven HIGH on reset (while IO0 is LOW), selects an unsupported SDIO boot mode, causing boot failure. | Strapping |
| IO4 | GPIO4 | Sampled at reset for boot config; should not be driven at boot (affects boot mode timing). | Strapping |
| IO5 | GPIO5 | Must be HIGH during boot; if pulled LOW at reset, alters SDIO slave timing and may prevent normal boot. | Strapping |
| IO12 | MTDI (GPIO12) | Keep LOW during boot (internal PD); pulling HIGH at reset selects 1.8V flash mode, causing flash brownout if 3.3V flash is used. | Strapping |
| IO13 | MTCK (GPIO13) | Used for JTAG debugging (TCK); avoid using as GPIO if JTAG is needed. | Other |
| IO14 | MTMS (GPIO14) | Used for JTAG debugging (TMS); driving it as GPIO may interfere with JTAG or produce spurious signals at boot. | Other |
| IO15 | MTDO (GPIO15) | Keep HIGH during boot (internal PU); if LOW on reset, bootloader log is silenced and boot mode may change. | Strapping |
| IO34 | GPIO34 | Cannot be used as output (no drive capability); only suitable for analog/digital input. | Other |
| IO35 | GPIO35 | Cannot be used as output; only suitable for input. | Other |
| IO36 | GPIO36 (SENSOR_VP) | Cannot be used as output; only suitable for input (e.g., analog read). | Other |
| IO39 | GPIO39 (SENSOR_VN) | Cannot be used as output; only suitable for input. | Other |
Only if you know the tricks
wired to flash or USB - expect a fight| Pin | Label | What to know | Role |
|---|---|---|---|
| IO16 | GPIO16 | Connected to internal PSRAM on PSRAM-enabled modules; not usable as GPIO on those modules. | Flash |
| IO17 | GPIO17 | Connected to internal PSRAM on PSRAM-enabled modules; not usable as GPIO on those modules. | Flash |
Pinout notes The WEMOS LOLIN32 Lite pinout brings out 26 pins at a 2.54 mm pitch - 23 usable GPIO alongside the 5V , GND and 3V3 power rails. On the analog side there are…
The WEMOS LOLIN32 Lite pinout brings out 26 pins at a 2.54 mm pitch - 23 usable GPIO alongside the 5V, GND and 3V3 power rails.
On the analog side there are 15 ADC-capable pins for sensors and battery monitoring.
If you want zero surprises, IO18, IO19, IO22, IO23 and 5 more are free of any such role - the safest first picks. 12 of the exposed pins carry boot-time or system duties on the ESP32 (IO0, IO2, IO4 and 9 more).
The LOLIN32 Lite pinout fans out 26 ESP32 GPIOs on two rows, mirroring the original D1-mini shield headers for easy stacking.
Power rails: use USB 5V (or VIN) as input, the regulated 3V3 pin for logic-level peripherals, and the dedicated BAT pin for a single-cell Li-Po. Multiple GND pads provide solid returns.
Serial: U0_TX (GPIO1) and U0_RX (GPIO3) connect to the CH340C for programming/logging. Need more ports? U2_TX (GPIO17) and U2_RX (GPIO16) are free for GPS or RS-485 transceivers.
I²C defaults to SDA (GPIO21) and SCL (GPIO22), broken out on the shield D2/D1 lines-but any spare GPIO can be reassigned.
SPI: the primary VSPI bus (best for OLEDs, SD adapters, radios) maps to MOSI (GPIO23), MISO (GPIO19), SCK (GPIO18), and CS (GPIO5). A secondary HSPI bus lives on GPIO12-15 when you need a second device.
Analog & touch: Eight ADC1 channels (GPIO32-GPIO39) work even with Wi-Fi on. Extra ADC2 pads (GPIO0, 2, 4, 12-15, 25-27) share RF hardware. Dual 8-bit DAC outputs are on GPIO25 and GPIO26. Ten pads double as capacitive-touch inputs-great for touch keys or wake-up gestures.
Every GPIO can generate high-resolution PWM (up to ≈40 kHz). Remember the boot-strap pins-GPIO0, GPIO2, and GPIO15-must sit HIGH (with proper pull-ups) on reset for a normal boot.
With battery charging, robust power rails, and a shield-friendly layout, the LOLIN32 Lite pinout makes it effortless to go from breadboard prototype to compact, battery-powered product.
Getting started
flash your first firmware in ~2 minutesBoard: Lolin32 Lite
Flash Size: 4MB · DIO
Upload Speed: 921600
// blink
pinMode(18, OUTPUT);
digitalWrite(18, LOW); // on (often inverted)[env:lolin32-lite]
platform = espressif32
board = esp32dev
framework = arduino
monitor_speed = 115200
upload_speed = 921600esp32:
board: esp32dev
variant: lolin32-lite
framework:
type: esp-idf
# blink - GPIO18
output:
- platform: gpio
pin: 18
id: led_out
light:
- platform: binary
name: "LED"
output: led_outesptool.py --chip esp32 --port /dev/ttyACM0 \
write_flash 0x0 firmware.binSpecifications
ESP32 · 58 × 25.4 mmAbout this board
At its core is the ESP32 - a dual-core Xtensa with both Bluetooth Classic and BLE.
Expect to pay about $5.00 - less than the ~$20 most ESP32 boards go for.
Onboard you'll find battery charging (TP4054) via JST-PH 2.0, status LEDs (Blue (GPIO22), Charge) and Reset buttons.
The WEMOS LOLIN32 Lite squeezes Espressif’s dual-core ESP32-WROOM-32 module into a slim 57 × 25 mm board that still accepts the classic LOLIN/D1-mini shield ecosystem. It ships with 4 MB of flash, runs up to 240 MHz, and offers both Wi-Fi 802.11 b/g/n and Bluetooth 4.2 (BR/EDR + BLE) for rock-solid wireless connectivity.
A low-cost CH340C USB-to-UART bridge handles programming and serial debugging via the Micro-USB port and supports auto-reset/boot so you can flash sketches without pushing buttons.
Onboard power management is Li-Po ready: a TP4054 charger (≈ 500 mA) and a PH-2 battery connector (BAT) let you run projects untethered while the board trickle-charges whenever USB is present.
Convenience extras include a RESET push-button, a BOOT (IO0) button for manual download-mode entry, and a bright blue on-board LED on GPIO 22 for quick status indication.
With 22 GPIOs (all PWM-capable), 12-bit ADCs, dual 8-bit DACs, 10 capacitive-touch pads, plus I²C, SPI, UART, SD-card, and RTC IO support, the LOLIN32 Lite punches far above its weight for battery-powered IoT nodes, wearables, or compact sensor gateways.
Where to buy
prices are typical street pricesResources
Similar boards
