The document discusses using the Raspberry Pi's GPIO pins to control hardware interfaces with Node-RED. It provides examples of creating Node-RED flows to: 1. Control an LED by setting a GPIO pin as a digital output and toggling it on and off. 2. Control LED brightness using PWM by setting a GPIO pin as a PWM output and changing the duty cycle. 3. Read input from a binary sensor by setting a GPIO pin as a digital input and reading its state. 4. Read temperature from a 1-Wire temperature sensor connected to the Raspberry Pi's 1-Wire bus using a Node-RED 1-Wire node.

1. 02 Raspberry Pi GPIO
Node-RED Control Hardware Interfaces

2. Raspberry Pi Interfaces
• One powerful feature of the Raspberry Pi is the row of GPIO
(general purpose input/output) pins along the edge of the
board, next to the yellow video out socket.
• These pins are a physical interface between the Pi and the
outside world.
• At the simplest level, you can think of them as switches that you
can turn on or off (input) or that the Pi can turn on or off (output)

3. Raspberry Pi Interfaces
• Seventeen of the 26 pins are GPIO pins; the
others are power or ground pins.
• It could be input from a sensor or a signal from
another computer or device
1
2
25
26

4. How GPIO Pins Work : Output
• When we use a GPIO pin as an output, pin can turn
on or off,or go HIGH or LOW in computing terms.
• When the pin is HIGH it outputs 3.3 volts (3v3).
• When the pin is LOW it outputs 0 volts (ground)

5. How GPIO Pins Work : Input
• When we use a GPIO pin as an input switch, pin
have to “pull up” or “pull down”.
pull up pull down

6. Node-RED Pi GPIO
• There are two main ways of interacting with a
Raspberry Pi using Node-RED
• rpi-gpio nodes, provided in the palette for
monitoring and controlling the GPIO pins. This is
the simplest and recommended way.
• wiring-pi module, this provides complete access
to the GPIO pins, and other devices, within
Function nodes.

7. Pin Map

8. Output Interface
Digital Output

9. Create Flow for Digital Out
• Add a inject, debug nodes and change parameter of
inject node, by double click

10. Create Flow for Digital Out
• Change the repeat into “interval” for every 1 second.
• Set Name to “tick every 1 sec”
Changed
Properties

11. Create Flow for Digital Out
• Add a function node and double click to edit
function.
Set function
name

12. Create Flow for Digital Out
• Add a rpi-gpio node (in part “Raspberry Pi”) and
double click to change pin number.
Pin 16
Digital Output Mode

13. Create Flow for Digital Out
Wiring node and click deploy

14. Create Flow for PWM Out
• Add 5 inject, 1 debug nodes and change parameter
of inject node, by double click

15. Create Flow for PWM Out
• Change inject node 1 properties
Changed
Properties

16. Create Flow for PWM Out
• Change inject node 2 properties
Changed
Properties

17. Create Flow for PWM Out
• Change inject node 3 properties
Changed
Properties

18. Create Flow for PWM Out
• Change inject node 4 properties
Changed
Properties

19. Create Flow for PWM Out
• Change inject node 5 properties
Changed
Properties

20. Create Flow for PWM Out
• Add a rpi-gpio node (in part “Raspberry Pi”) and
double click to change pin number and PWM.
Pin 16
PWM Output Mode

21. Create Flow for PWM Out
Wiring node and click deploy

22. Create Flow for PWM Out
Click on the each Inject button to change LED bright

23. Input Interface
Vcc
GND
Data Out
Digital Input

24. Create Flow for Binary Sensor Input
• Add a rpi-gpio node (in part “Raspberry Pi”) and
double click to change pin number and resistor.
Pin 11
no resistor

25. Create Flow for Binary Sensor Input
• Add a function node and double click to edit
function with 2 output.
Set function name
and output

26. Create Flow for Digital Out
• Add a rpi-gpio node (in part “Raspberry Pi”) and
double click to change pin number.
Pin 16
Digital Output Mode

27. Create Flow for Binary Sensor Input
Add debug node and
wiring node and click deploy

28. Special Input Interface
1-Wire
1-Wire bus

29. Special Input Interface
#Open new Putty to connect R-Pi 10.10.11.X using SSH!
User : pi!
Password : raspberry!
!
pi@thethingbox$ls /sys/bus/w1/devices!
!
!
!
!
!
- Copy the number (Sensor ID) in rectangular for use with Node-
RED!
!
pi@thethingbox$exit!

30. Create Flow for 1-Wire Bus
• Add a inject, debug nodes and change parameter of
inject node, by double click

31. Create Flow for 1-Wire Bus
• Change inject node properties
• Payload : blank, Topic : Sensor ID, Name : DS1820 , Repeat :
30 Second
Changed
Properties

32. Create Flow for 1-Wire Bus
• Add a 1-Wire and change node (in part “function”)
and double click on change node.
• Set retain last value of sensor data
Retain last
value

33. Create Flow for 1-Wire Bus
• Add a mqtt node (in part “output”) and double
click to change mqtt broker, and Topic.
Set mqtt broker

34. Create Flow for 1-Wire Bus
Wiring node and click deploy

35. Create Flow for 1-Wire Bus
Monitor
Temperature
with MyMQTT
App on
Android