NodeMCU-32S (ESP32): specs and pinout
ESP32 development board sold as the Ai-Thinker NodeMCU-32S with an IPEX antenna connector. No maker document for the board is available, so this page gives ESP32 chip facts only.
Specs
| Spec | Value | Source |
|---|---|---|
| Supply voltage (chip) | 2.3 V / 3.0 V min, 3.3 V typ, 3.6 V max (3.0 V min for chips with 3.3 V in-package flash or PSRAM) | source Table 5-2 Recommended Power Supply Characteristics, note 2 (p.51) |
| Recommended supply current | 500 mA or more from the supply | source Table 5-2 (p.51) |
| Wireless | 2.4 GHz Wi-Fi (802.11 b/g/n) plus Bluetooth v4.2 BR/EDR and BLE | source Cover page and features (p.1, p.3) |
| GPIO count (chip) | 34 programmable GPIOs, six of them input-only | source Features, Advanced Peripheral Interfaces (p.4) |
| ADC | 12-bit SAR ADC, up to 18 channels | source Features (p.4) |
| Pin source current | 40 mA typ (VDD3P3_CPU / VDD3P3_RTC domains, VDD 3.3 V, VOH >= 2.64 V) | source Table 5-3 DC Characteristics (p.52) |
| Pin sink current | 28 mA typ (VDD 3.3 V, VOL = 0.495 V) | source Table 5-3 DC Characteristics (p.52) |
| Input high level VIH | 0.75 x VDD min, VDD + 0.3 V max | source Table 5-3 DC Characteristics (p.52) |
Power
| Value | Source | |
|---|---|---|
| Supply | 2.3/3.0 V to 3.6 V at the chip | source Table 5-2 (p.51), Table 5-4 (p.52) |
| Current | Wi-Fi TX 240 mA (802.11b, 19.5 dBm), 190 mA (11g, 16 dBm), 180 mA (11n, 14 dBm); RX 95 to 100 mA | source Table 5-2 (p.51), Table 5-4 (p.52) |
Chip pins
These are the pins of the chip on the module, from the chip datasheet. The module's own header may label or expose them differently.
No official Ai-Thinker NodeMCU-32S document was available. Only ESP32 chip facts are shown: the board header order, which chip pins the header carries, the regulator and the USB serial chip are not covered. The four rows below are chip pins GPIO34, 35, 36 and 39; GPIO37 and GPIO38 are not listed because no document shows they are brought out.
| Pin | Function | Voltage | Notes | Source |
|---|---|---|---|---|
| GPIO34 (VDET_1) | ADC1_CH6, RTC_GPIO4 | Chip-level: pin type I (input only) on the ESP32 chip; the board header label for this GPIO is not documented | source Table 2-1 Pin Description (p.14) | |
| GPIO35 (VDET_2) | ADC1_CH7, RTC_GPIO5 | Chip-level: pin type I (input only) on the ESP32 chip; the board header label for this GPIO is not documented | source Table 2-1 Pin Description (p.14) | |
| GPIO36 (SENSOR_VP) | ADC1_CH0, RTC_GPIO0 | Chip-level: pin type I (input only) on the ESP32 chip; the board header label for this GPIO is not documented | source Table 2-1 Pin Description (p.14) | |
| GPIO39 (SENSOR_VN) | ADC1_CH3, RTC_GPIO3 | Chip-level: pin type I (input only) on the ESP32 chip; the board header label for this GPIO is not documented | source Table 2-1 Pin Description (p.14) |
Build with it
Project ideas for the NodeMCU-32S (ESP32). Each link opens Soldr with the prompt filled in; Soldr assigns the pins, checks power and shows how to wire every part.
- Wi-Fi plant watering reminder: The analog sensor goes to an ADC1 pin; a learning project, calibrate dry and wet values yourself.
- Temperature and humidity dashboard: One digital pin reads the DHT22 and the board serves the readings over Wi-Fi.
- Wi-Fi DC current and voltage logger: The INA219 chip runs from 3 to 5.5 V and measures bus voltage from 0 to 26 V over I2C (TI datasheet, Features and Operating supply range), so it can share the ESP32 3.3 V I2C lines; the CJMCU module itself is not documented, so check its markings. Learning project: keep the measured circuit low-voltage.
- Light level logger: Reads the module analog output on an ADC1 pin; keep the output at or below 3.3 V.
Common mistakes
- Do not feed 5 V into a GPIO: the input high level maximum is VDD + 0.3 V (source: link, Table 5-3, p.52).
- GPIO34, 35, 36 and 39 are input-only; they cannot drive an output (source: link, Table 2-1 pin description, p.14).
- Wi-Fi transmit draws about 240 mA, so use a supply rated for 500 mA or more (source: link, Table 5-2 p.51, Table 5-4 p.52).
Not covered by the official source
- No maker document is available for the Ai-Thinker NodeMCU-32S board, so no board pinout is given.
- Chip temperature range depends on whether the module has in-package flash, so it is not given.
- Which ESP32 module (for example ESP-WROOM-32S) is fitted is not confirmed by an official document.
Sources
- link (ESP32 Series Datasheet v5.3, Espressif)