Lua module for Pi

RPi.GPIO.Lua-Workshop on 6/28/2014!

Lua module for Raspberry Pi

This package provides a Lua module to control the GPIO pins on a Raspberry Pi.

The main functionality is provided by the RPi.GPIO Python Module of Ben Croston.
The following functions have been implemented for Lua:

Pin functions:

setup
cleanup
input
output
setmode
gpio_function
setwarnings

Interrupts and events:

wait_for_edge
event_detected
add_event_detect
remove_event_detect
add_event_callback

PWM:

newPWM
start
ChangeFrequency
ChangeDutyCycle
stop

Installation (manual)

Download the two tarballs referenced below and follow the inclided instructions.

Installation (luarocks package, instructions for Raspbian)

sudo apt-get install lua5.1 liblua5.1-0-dev
sudo apt-get install luarocks

sudo luarocks install rpi-gpio

# for PWM and events:
sudo luarocks install copas
sudo luarocks install darksidesync

# for the GPIO.lcd-hd44780 module:
sudo luarocks install bit32

Example: Simon-Game

Simon is a electronic memory game: Four LEDs are lighting up in random order, each LEDs comes along with a specific sound. The player presses a button for each LED. If the sequence was entered correctly, the next round will add a new LED.

Preparation:

connect 4 LEDs and 5 push buttons to the Pi GPIO connector (see the arrays buttons and leds)
connect speakers to your Pi
copy beep*.ogg files from ~/python_games to your script directory
adjust sound volume: amixer cset numid=1 -- 100%
install ogg123: sudo apt-get install vorbis-tools
if Unknown PCM cards.pcm.front is logged: Replace "pcm.front cards.pcm.front" by "pcm.front cards.pcm.default" in /usr/share/alsa/alsa.conf

01 GPIO=require "GPIO"
02 
03 btnExit = 21
04 buttons = {7, 15, 13, 11, btnExit}
05 leds={12, 16, 18, 26}
06 
07 GPIO.setmode(GPIO.BOARD)
08 GPIO.setwarnings(False)
09 math.randomseed(os.time())
10 
11 for k,v in pairs(buttons) do
12   GPIO.setup(v, GPIO.IN,  GPIO.PUD_DOWN)
13 end
14 
15 for k,v in pairs(leds) do
16   GPIO.setup(v, GPIO.OUT)
17 end
18 
19 flashLED = function (cycles) 
20   for x=1, cycles*2 do
21     for k,v in pairs(leds) do 
22       GPIO.output(v, x%2); 
23     end
24     os.execute("sleep 0.2")
25   end
26 end
27 
28 beep = function(num, wait)
29   GPIO.output(leds[num], 1)
30   os.execute("ogg123 --quiet -K1 beep"..num..".ogg")
31   GPIO.output(leds[num], 0)
32   if wait==true then os.execute("sleep 0.1") end
33 end
34 
35 quit=function()
36   GPIO.cleanup()
37   os.exit()
38 end
39 
40 flashLED(3)
41 
42 playlist = {}
43 
44 while true do
45   
46   playlist[#playlist+1] = math.random(4)
47   
48   for k,v in pairs (playlist) do
49     beep(v, true)
50   end
51   
52   for k,v in pairs (playlist) do
53     waitForUser=true
54     while waitForUser do
55       
56       for kb,vb in pairs(buttons) do 
57         if GPIO.input(vb) == true then
58           if (vb~=buttons[v]) then 
59 	    if vb~=btnExit then os.execute("ogg123 --quiet gameover.ogg") end
60 	    quit()
61           else 
62  	    beep(v, false)
63           end
64           waitForUser=false
65         end
66       end
67     end
68   end
69   
70   flashLED(1) 
71 end

Downloads (0.1)

RPi.GPIO.Lua module (5 KB)

RPi.GPIO module

Downloads (Fork including PWM and Events, 0.2.x)

Pi&More 5 presentation

Slides and sample code (1.1 MB)