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WIO_01 Input/Output with WIFI communiction.

Copyright Rob Versluis and Peter Giling


Newer members of the Arduino supported family of units, this one specially made us curious.
Development of sketches for this Wemos D1 or Lolin D1 was a challenge wich resulted in a very complete piece of software.
A large memory capacity, and Configuration of the unit via Rocrail made it possible to create one sketch, covering all
planned and/or required tasks.
The unit enables a wide variety of connections, but through restrictions in timing, , some functions have to be chosen for.:

  • 32 x Programmable input /output ports, which are always available.
  • 2 x RFID sensors
  • 4 x servo motors, where Rocrail provides a very easy adjusting options.
  • 2 x I2C connectors, for example to connect displays.
  • 128 2503 leds on one line
  • supply power for I2C connections, selectable for 3.3 or 5 Volt
  • BS1 connector for booster like ORD-3

Switching Power supply

More and more very nice power supplies are available, making the use of transformers 'out of date'.
All systems on board work with 3.3 or 5 Volt.
But making a 5 Volt power line, is not a good idea.
The power loss in many occasions might come unacceptable for a certain task, like servo's.
Therefore, this board is equipped with a switching regulator, and the power supply for this unit can be anything between 12 and 24 Volt dc or between 10 and 18 Volt ac.
The total VA (Volt x Ampere) should be at least 20 VA.
So also a normal train transformer is useful here.
The switching regulator has a selection for the output voltage, which should be set to 5V.
It can be done by the on-board trimmer, but I prefer to use the voltage selector on the bottom side of the regulator board.
Taking off the trimmer totally, assures that no accidental voltage change can occur.
This will be the way kits will be configured.
The used processor here, Lolin D1 Mini, only provides a few I/O pins, so a combination of various functions
is not always possible, since they work on the same pin.
But the configuration in Rocrail will provide a simple selection of the desired task.

further info

Since this board is using same firmware as other WIO related units, the complete concept
is explained in one page.


Hardware connections

WIO_01 contains many connection options.

I/O 1 to I/O 4

Pin #
1 +5V +5V +5V +5V
3 port 1 port 9 port 17 port 25
4 port 2 port 10 port 18 port 26
5 port 3 port 11 port 19 port 27
6 port 4 port 12 port 20 port 28
7 port 5 port 13 port 21 port 29
8 port 6 port 14 port 22 port 30
9 port 7 port 15 port 23 port 31
10 port 8 port 16 port 24 port 32

Se1 - Se4 Servomotors

Se1 to Se4 servomotor
PINFunctionwire colour
1 Pulse or
2 +5V re
3 GND br

I2C1 and I2C2

Both connectors are linked together all 4 pins.
The power to these connectors can be selceted with between 5V and 3,3V by Jp1.
See indication on pcboard.

Pins function
4 5V / 3,3V 5V / 3,3V

RC1 Railcom

This is a standard serial connector, which can be used to connect variious units, as far as WIO support them.
Examples are:

  • GCA214 Railcom unit (under development)

^ Pinsetting RC1 ^

pin # function
1 + 5V
3 txd
4 rxd

BS1 booster connector

This connection was planned to use for connection booster, long before WIOCtrl was developed.
BS1 is still useable to drive a universal booster like ORD-3 or ORD-VC-1.

Pin # function
1 DCC line 1
2 DCC line 2
4 Short circuit
5 current sensor

FL1 Fastled

To connect a chain of 2812 Leds, (max 128).
The limit is absolute 128, but with all leds full on, the power supply is by far not sufficient.
In that case, external 5V supply should be used to connect to the led chain.

Pinsetting FL1
PIN # Function
1 Signal
2 +5V

RC522-1 and RC522-2 RFID sensors

For use with RC522 sensors.
The pins are one to one identical with the RC522 sensors.
PIN5 and PIN7 does have to be wired, but wiring will do no harm.
More about the RC522 RFID sensor can be found here:

gca-wio-en.txt · Last modified: 2021/02/25 18:58 by phg