IR trigger for Sony Nex cameras

[hansel]

The attached script triggers a Sony NEX camera every 5 seconds by sending the appropriate pulses to an IR LED connected to pin X2.

This will be part of a larger project (remotely controlled camera rig). I post this 'snippet' her in case somebody would need something similar. It can be adapted easily to send any IR code once you know what it looks like

PS: this is my first attempt at Python...

Code: Select all

""" 
Trigger a Sony Nex camera every 5 seconds
The IR LED (in series with a 100 ohm resistance) is connected 
from pin X2 to ground 

Good Sony IR description:  http://www.cypress.com/?docID=46755
"""

import pyb
import micropython
micropython.alloc_emergency_exception_buf(100)

class IRState:
  def __init__(self):
    self.cnt=-1
    self.data=0
    self.cells=""
    
  def nextVal(self):
    if self.cnt<0 or self.cnt>=len(self.cells):
      self.cnt = -1
      val = 'x'
    else:
      val = self.cells[self.cnt]
      self.cnt = self.cnt+1
    return val
      
  def send(self, s):
    if self.cnt >=0:
      print ('send: busy')
    self.cells = s
    self.cnt = 0

timer = pyb.Timer(2, freq=40000)
ch2 = timer.channel(2, pyb.Timer.PWM, pin=pyb.Pin.board.X2, pulse_width_percent=50)

irs = IRState()
def cb(filter):
  global irs
  val = irs.nextVal()
  if val=='m':
      ch2.pulse_width_percent(20)
  else:
      ch2.pulse_width_percent(0)
  
modulator = pyb.Timer(1, freq=1666) # 1666 Hz -> 600 us cells
modulator.callback(cb)

S = 'mmmms'    # start: 2400 us on 600 us off
I = 'mms'      # 1 bit: 1200 us on 600 us off
O = 'ms'       # 0 bit:  600 us on 600 us off
P='ssssssssssssssssssss'  #pause

code = S+ I+O+I+I +O+I+O+O + I+O+I+I + I+O+O+O + I+I+I+I
all = code + P + code + P + code + P + code   # 4 transmissions

while True:
  irs.send(all)
  pyb.delay(5000)