Changes between Version 6 and Version 7 of HackingIRDongle


Ignore:
Timestamp:
11/21/12 12:52:00 (7 years ago)
Author:
hz
Comment:

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  • HackingIRDongle

    v6 v7  
    4444 
    4545Remember there should be some space between two commands, from 30ms to 80ms. 
     46 
     47= Hack Android app i-helicopter with Audacity = 
     48 
     49This is just a guide. 
     50 
     51Download i-helicopter from play store. 
     52Use a dual head audio cable to connect audio jack of android device to line-in/microphone in laptop, run the app, turn volume up to highest, and move the throttle to a middle point.  
     53Start recording with Audacity. The left channel is the IR code without carrier, the right channel is IR code with carrier. 
     54IR code in audio/wave format is pretty easy to understand: 
     55 
     56small volume 
     57[[Image(wiki:Attachments:Small_volume.png)]] 
     58 
     59middle volume 
     60[[Image(wiki:Attachments:Middle_Volume.png)]] 
     61 
     62 
     63MAX Volume 
     64[[Image(wiki:Attachments:Max_Volume.png)]] 
     65 
     66You can tell from the pictures, that the signal is originally a sine wave. With volume going up, the signal gets cut off and then becomes a square wave, which is the IR Code we want to send out. (that's why we need to turn the volume up to max to use the IR dongle). 
     67 
     68The red part is the two starting bit. The yellow part is the 29 bit control code (not fully displayed in picture). 
     69 
     70There are only two different period in the sine wave, as marked in the first picture(yellow on top). The bigger one has a period of 1.6ms, the small one has a period of 0.8ms ,give or take. These two period corresponding to the two different bit in the instructables (7 and 4). 
     71 
     72Notice the green part in picture Small_volume.png. The starting bit is different. These two starting bit have two period for the upper part and lower part of sine wave. The upper part corresponding to "HIGH" in square wave, the lower part corresponding to "LOW" in square wave.  
     73 
     74The protocol is exactly the same with the remote version, just substitute "1" and "0" with 1.6ms period sine wave and 0.8ms period sine wave.