1. Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.
    Dismiss Notice

Turn Your IPod Into A Universal Remote

Discussion in 'Electronic Projects' started by DragonMaster0121, Jul 9, 2005.

Thread Status:
Not open for further replies.
  1. gregmcc

    gregmcc Member

    Joined:
    Aug 20, 2005
    Messages:
    303
    Likes:
    0
    Location:
    Darwen, UK
    I've tried 2 IR's with a 220R resistor - can't seem to get it to work. Also can't seem to find the IR device on the griffin site - do they still make it?
     
  2. ecoy28

    ecoy28 New Member

    Joined:
    Jul 26, 2006
    Messages:
    16
    Likes:
    0
    got the receiver running and recording. the problem now's the transmitter. seem's that it can't get enough juice from the audio output of the headphones socket. using a digicam, can't see any light(digicams can see IR)
     
  3. audioguru

    audioguru Well-Known Member Most Helpful Member

    Joined:
    Mar 16, 2004
    Messages:
    32,437
    Likes:
    933
    Location:
    Canada, of course!
    A headphones output is not powerful enough to light an LED. You need to light the LED with its resistor with a DC power supply or battery then modulate the DC with the audio from the headphones jack capacitor-coupled to it.
     
  4. dave

    Dave New Member

    Joined:
    Jan 12, 1997
    Messages:
    -
    Likes:
    0


     
  5. ecoy28

    ecoy28 New Member

    Joined:
    Jul 26, 2006
    Messages:
    16
    Likes:
    0

    i see, i see. that's what i've been tryin to do. haven't got it right yet though. a little help on a diagram. thanks
     
  6. audioguru

    audioguru Well-Known Member Most Helpful Member

    Joined:
    Mar 16, 2004
    Messages:
    32,437
    Likes:
    933
    Location:
    Canada, of course!
    To calculate the correct value of a current-limiting resistor for the IR LED, we need to know its forward voltage at 20mA and its max continuous current ratings. We also need to know the supply voltage of the transmitter and which type of battery it uses.
     
  7. ecoy28

    ecoy28 New Member

    Joined:
    Jul 26, 2006
    Messages:
    16
    Likes:
    0
    will try to see what i can do. I'd like to ask more questions/guidance next time. si i cloud just use a dry cell(batt) and put it in series with the IR transmitter-Resistor combo. how bout the capacitor?
     
  8. audioguru

    audioguru Well-Known Member Most Helpful Member

    Joined:
    Mar 16, 2004
    Messages:
    32,437
    Likes:
    933
    Location:
    Canada, of course!
    An IR LED needs about 1.2V at about 15mA. A 3V battery and two 62 ohm resistors in series with the IR LED would produce 15mA. The audio from the headphones jack would feed through a 470uF capacitor to the junction of the two resistors. Then the IR LED would be AM modulated by the sound. The headphones output would have a 31 ohms load.
     
  9. ecoy28

    ecoy28 New Member

    Joined:
    Jul 26, 2006
    Messages:
    16
    Likes:
    0
    muchas gracias, will try , will try.

    would update you
     
  10. ecoy28

    ecoy28 New Member

    Joined:
    Jul 26, 2006
    Messages:
    16
    Likes:
    0
    receiver

    the receiver that i've made is connected to the printer port. the data it receives is not in audio( mp3, wav) how can i get the input from the remote via the microphone jack? in that way, the IR would be in audio format.
     
  11. Sceadwian

    Sceadwian Banned

    Joined:
    Oct 27, 2006
    Messages:
    14,047
    Likes:
    141
    Location:
    Rochester, US
    Sample it using a 96khz capable audio card.
     
    Last edited: Mar 29, 2007
  12. ecoy28

    ecoy28 New Member

    Joined:
    Jul 26, 2006
    Messages:
    16
    Likes:
    0
    what do you mean? i'm askin how i could input the ir through the microphone jack? what circuit could i use?
     
  13. Sceadwian

    Sceadwian Banned

    Joined:
    Oct 27, 2006
    Messages:
    14,047
    Likes:
    141
    Location:
    Rochester, US
    Exactly what I said. Just feed the IR sensor output directly to the microphone jack, no circuit. The sound cards microphone pre-amp will amplify the signal sufficently for detection, even if it didn't most IR sensors should produce enough voltage to be detectable on a sound card with 16 bit samples.
     
  14. ecoy28

    ecoy28 New Member

    Joined:
    Jul 26, 2006
    Messages:
    16
    Likes:
    0
    no phototransistor?

    you mean, i won't even need a phototransistor? i'll just align the remote to the mic port and click?!
     
  15. ecoy28

    ecoy28 New Member

    Joined:
    Jul 26, 2006
    Messages:
    16
    Likes:
    0
    it doesn't work
     
  16. audioguru

    audioguru Well-Known Member Most Helpful Member

    Joined:
    Mar 16, 2004
    Messages:
    32,437
    Likes:
    933
    Location:
    Canada, of course!
    A photo-diode is an IR sensor that will have a low level signal when it receives close-up IR radiated data.
    But I doubt that a mic input can pickup 38kHz IR modulation. It probably cuts frequencies above 20kHz.
     
  17. ecoy28

    ecoy28 New Member

    Joined:
    Jul 26, 2006
    Messages:
    16
    Likes:
    0
    what do i do? how can i sample the ir and save it in audio format
     
  18. Sceadwian

    Sceadwian Banned

    Joined:
    Oct 27, 2006
    Messages:
    14,047
    Likes:
    141
    Location:
    Rochester, US
    I was thinking more along the lines of a photodiode directly connected to the MIC input.
     
  19. ecoy28

    ecoy28 New Member

    Joined:
    Jul 26, 2006
    Messages:
    16
    Likes:
    0
    up to how much hertz can the mic input samp
    le?
     
  20. Sceadwian

    Sceadwian Banned

    Joined:
    Oct 27, 2006
    Messages:
    14,047
    Likes:
    141
    Location:
    Rochester, US
    Depends on your sound card, but most go up to 96khz, like I said though some of them have a 22khz low pass filter on the input regardless of the 96khz sampling rate (the increased sampling rate is for stereo seperation in the higher frequency ranges) On my card it appears that cut off frequency is pretty sharp, but you'd have to test it yourself. Worse case you're going to at least be able to see the modulation.
     
  21. ecoy28

    ecoy28 New Member

    Joined:
    Jul 26, 2006
    Messages:
    16
    Likes:
    0
    i dohope i could get it workin. i think my audio card is integrated to my motherboard. tried to look up for it's sampling rate in the control panel. wasn't able to find it.
     
Thread Status:
Not open for further replies.

Share This Page