active poll to sleep for proxmark3 RFID example

experiment/production/PIU-Notes.md

@@ -84,6 +84,7 @@ local bin = require('bin')
 local utils = require('utils')
 local format=string.format
 local floor=math.floor
+local os = require("os")
 
 function sleep (a)
     local sec = tonumber(os.clock() + a);
@@ -98,7 +99,7 @@ local function main(args)
   -- core.console will go async when waiting for the proxmark to return
   -- so need to wait for a response (sleep)
   core.console('lf hid read')
-  sleep(30) -- run for 30 seconds
+  os.execute("sleep 30")
 
   print( string.rep('--',30) )
 
@@ -107,8 +108,7 @@ main(args)
 
 ```
 
-Note that his is an active poll so it's worth investigating how to alleviate some of the pressure in the while loop.
-The following script should be put into the `scripts` directory and can be run via:
+The script should be put into the `scripts` directory and can be run via:
 
 ```
 $ stdbuf -eL -oL ./proxmark3 /dev/ttyACM0 -l lf-hid-read.lua | tee test.log