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WIO-03 ESP32 16 I/O


The WIOesp IO16 type is based on the ESP32 which provides 16 I/O onboard.
A PCB is developed by GCA which is based on the Wemos D1 Mini ESP32 pin layout. It is compact sized and measures only 66 x 44mm.


Feature Connector Pin Remark Mapped I/O Pins
16 x I/O IO1 + IO2 1-8, 1-8 3V3, GCA compatible
64 x NeoPixel NP1 WS2811
4 x Servo servo 1-4 or, re, br IO1 pin 1-4
I2C I2C1 Displays, Sensors, …
UART UART1 ID12LA, RailCom, … (Tx and Rx are swapped)
Stepper motor IO1 1-4 3W Fast is supported IO1 pin 1-4
2 x Charlyplexing IO1 1-4, 5-8 LED signals IO1 pin 1-8
Hall sensor NP1 Speed and distance (Mutual exclusive with NeoPixel)

Note: Mapped I/O pins can not be used as normal I/O in case the mapping option has been activated.


4xonboard or 16x with PCA9685-Modul over I2C
To use 16 Servos set the Servo_MAX Value in USERCNF.h to 16 (standard is 4)
#define SERVO_MAX 4

PSK Pinlayout



  • Neopixel and Servo are mutual exclusive.
  • NeoPixel, Servo, Stepper and Charliplexing are activated on the fly. The first type command will exclude other possibilities.



Part Value Remark
R5 150kOhm Battery monitoring 2S Li-ION
R6 47kOhm Battery monitoring 2S Li-ION



The NeoPixel pin will be used as interrupt input for counting the Hall sensor ticks.
Setting the wheel diameter in the locomotive or wagon properties will calculate distance and speed.


wio/wio03-io16-en.txt · Last modified: 2022/07/28 11:19 by rjversluis