Minimal implementation of Passersby synth engine on norns.

hello_passersby.lua

-- Hello Passersby
-- 1.1.1 @markeats
--
-- Passersby demo script.
--

local Passersby = require "passersby/lib/passersby_engine"
local MusicUtil = require "musicutil"

engine.name = "Passersby"

local note_num
local count = 1

function init()
  
  Passersby.add_params()
  
  local note_metro = metro.init()
  note_metro.event = function()
    
    if count % 2 == 0 then
      -- Note off
      engine.noteOff(note_num)
      
    else
      -- Note on
      note_num = math.random(45, 69)
      engine.noteOn(note_num, MusicUtil.note_num_to_freq(note_num), 1) -- noteOn requires: id, frequency (hz), velocity (0-1)
    end
    
    count = (count + 1 - 1) % 2 + 1
    
  end
  note_metro:start(0.25)
  
  redraw()
end

function redraw()
  screen.clear()
  screen.aa(1)
  screen.level(15)
  screen.move(5, 10)
  screen.text("Hello Passersby")
  screen.update()
end