02 Raspberry Pi GPIONode-RED Control Hardware Interfaces

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)

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

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)

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

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.

Pin Map

Output InterfaceDigital Output

Create Flow for Digital Out

• Add a inject, debug nodes and change parameter of inject node, by double click

Create Flow for Digital Out• Change the repeat into “interval” for every 1 second.

• Set Name to “tick every 1 sec”

Changed Properties

Create Flow for Digital Out• Add a function node and double click to edit

function.Set function

name

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

Create Flow for Digital OutWiring node and click deploy

Create Flow for PWM Out

• Add 5 inject, 1 debug nodes and change parameter of inject node, by double click

Create Flow for PWM Out• Change inject node 1 properties

Changed Properties

Create Flow for PWM Out• Change inject node 2 properties

Changed Properties

Create Flow for PWM Out• Change inject node 3 properties

Changed Properties

Create Flow for PWM Out• Change inject node 4 properties

Changed Properties

Create Flow for PWM Out• Change inject node 5 properties

Changed Properties

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

Create Flow for PWM OutWiring node and click deploy

Create Flow for PWM OutClick on the each Inject button to change LED bright

Input Interface

VccGND

Data Out

Digital Input

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

Create Flow for Binary Sensor Input• Add a function node and double click to edit

function with 2 output.Set function name

and output

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

Create Flow for Binary Sensor InputAdd debug node and

wiring node and click deploy

Special Input Interface

1-Wire

1-Wire bus

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!

Create Flow for 1-Wire Bus

• Add a inject, debug nodes and change parameter of inject node, by double click

Create Flow for 1-Wire Bus• Change inject node properties

• Payload : blank, Topic : Sensor ID, Name : DS1820 , Repeat : 30 Second

Changed Properties

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

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

Create Flow for 1-Wire BusWiring node and click deploy

Create Flow for 1-Wire Bus

Monitor Temperature with MyMQTT

App on Android