Exercises

RF transmitter and Alexa

1. RF remote controller (4 channels)

Make a 433 MHz RF remote control to turn on / off 4 radio controlled sockets.

Required material: an RF transmitter.

Transmitter connections: Vcc: 3.3V, Gnd: GND, data: d2.

Sketch

--- Pin connections

rf :: d2

--- Commands

start = [s1=0,s2=0,s3=0,s4=0]

sock1=[rfch='1000010000',rf=s1]

sock2=[rfch='1000001000',rf=s2]

sock3=[rfch='1000000100',rf=s3]

sock4=[rfch='1000000010',rf=s4]

--- Rules

!s1 -> sock1

!s2 -> sock2

!s3 -> sock3

!s4 -> sock4

 s1 -> sock1

 s2 -> sock2

 s3 -> sock3

 s4 -> sock4

Meaning of the variables

s1: state of the socket 1
s2: state of the socket 2
s3: state of the socket 3
s4: state of the socket 4

Use

Setting s1=1 turns on socket 1. Setting s1=0 turns off socket 1

Note

Since the action of the two rules

!s1 -> sock1

 s1 -> sock1

is the same you are tempted to do the OR of the predicates

 !s1 | s1 -> sock1

But it will never work because x! | x is always true (tautology) so it will never vary. Because rules and events are activated when the predicate becomes true, this will never happen.

2. Alexa and RF remote controller

In Exercise 1, add a voice user interface (VUI) to control:

Heater
Lamp
Printer
Television.

Configuration

voxkey = "xf73702aa-f9de-43cb-B25D-9693884a3c25"

Sketch

--- Events

Heater = Voxdev=='5bf52e06861813419eab830e'

Lamp = Voxdev=='5beddc335f94a3052ae72811'

Printer = Voxdev=='5bf4b3e9eb220f3c039cf752'

Television = Voxdev=='5bf52d59861813419eab830d'

ON = Voxval=='ON'

OFF = Voxval=='OFF'

--- Commands

start = [v=0,mqtt=0,wifi=1]

--- Rules

Wificon -> vox=1

ON -> v=1

OFF -> v=0

Heater -> [rfch='1000010000',rf=v] ##

Lamp -> [rfch='1000001000',rf=v] ##

Printer -> [rfch='1000000100',rf=v] ##

Television -> [rfch='1000000010',rf=v] ##

To track all messages sent by Alexa add:

--- Rules

Voxcom -> [Voxdev,Voxcom,Voxval]

Note 1: if you use Google Home the ON and OFF definitions OFF become:

--- Events

ON = true<<Voxval

OFF = false<<Voxval

Note 2: if you use Alexa and Google Home at the same time the ON and OFF definitions OFF become:

--- Events

ON = Voxval=='ON' | true<<Voxval

OFF = Voxval=='OFF' | false<<Voxval

Note 2: you can compare a part of the device code (Voxdev) using the '== *' "ends with" relationship.

--- Events

Heater = Voxdev==*'830e'

Lamp = Voxdev==*'2811'

Printer = Voxdev==*'f752'

Television = Voxdev==*'830d'

Use with Alexa

Saying "Alexa, turn on the Lamp", Alexa sends this message to Smick

{"Voxdev": "'5beddc335f94a3052ae72811'", "Voxcom": "'setPowerState'", "Voxval": "'ON'"}

Saying "Alexa, turn off the Lamp", Alexa sends this message to Smick

{"Voxdev": "'5beddc335f94a3052ae72811'", "Voxcom": "'setPowerState'", "Voxval": "'OFF'"}

Lamp is an event defined as:

Lamp = Voxdev=="5beddc335f94a3052ae72811"

or in short form

Lamp = Voxdev==*"2811"

Events ON and OFF are so defined:

--- Events

ON = Voxval=='ON'

OFF = Voxval'OFF'

and they set or reset the variable v

ON -> v=1

OFF -> v=0

This simple rule:

Lamp -> [rfch='1000001000',rf=v] ##

will be activated when the message is received and with the command [rfch='1000001000',rf=v] you send turn-on RF code if v = 1 or send turn-off RF code if v = 0.

Use with Google Home

Saying "Ok Google, turn on the Lamp", Google Home sends this message to Smick

{"Voxdev": '5beddc335f94a3052ae72811', Voxcom='action.devices.commands.OnOff',Voxval='{"on":true}'}