Activities/Butialo

Butialo is a user-friendly environment that allows programming of the Butiá in the Lua language. Lua is a simple imperative scripting language but can create sophisticated programs. It is a dynamic language with automatic memory management and is extremely fast. Butialo is a derivative of the Pippy IDE (Python environment provided with the XO), which simplifies the creation of programs for the presence of components connected to the Butiá and offering snippets of code to access them.

The authoritative documentation is in the Spanish language at [1]

Installation

Download the Activity at [2]

Simple example

Move forward until there is an obstacle.

Motores.setvel2mtr( 1, 500, 1, 500 )
while true do
  local dist = Dist.getDistancia()
  if dist<700 then
     Motores.setvel2mtr( 1, 0, 1, 0 )
     repeat
        wait(1)
        dist = Dist.getDistancia()
     until dist > 700
     Motores.setvel2mtr( 1, 500, 1, 500 )
  end
end

Can also be programmed with events. The previous program is equivalent to the following:

local function adelante()   -- adelante is Spanish for forward or proceed
 Motores.setvel2mtr( 1, 500, 1, 500 )
end
local function esperar()    -- esperar is Spanish for wait
 Motores.setvel2mtr( 1, 0, 1, 0 )
 wait( 1 )
end

events.add( Dist.getDistancia, '<', 700, esperar )
events.add( Dist.getDistancia, '>', 700, adelante )
events.go()

Simple example (other)

Butia with dynamic stability. Take a Butiá, remove idler wheels and place an IR distance sensor pointing to the floor. The button toggles the behavior.

local d        --measured distance
local eq       --equilibrium position of d
local v        --calculated velocity

while true do
   print ("Press the button to start")
   repeat until Boton.getBoton()==1
 
   eq = Dist.getDistancia() 
 
   print("Starting", eq)
   util.wait(1)
 
   repeat
       d = Dist.getDistancia()
       v = 100+5*math.abs(d-eq)
       if v > 1024 then v = 1024 end
       if d < eq then
           Motores.setvel2mtr(1, v, 1, v)
       else
           Motores.setvel2mtr(0, v, 0, v)
       end
   until Boton.getBoton()==1
 
   print("Finished")
   Motores.setvel2mtr(1, 0, 1, 0)
   util.wait(1)
end

Video

Util

Butialo provides various auxiliary functions.

util.wait (t)

Pauses program execution for t seconds.

util.get_time ()

Returns the system time, in seconds.

Continue reading in Spanish

[3]