tag:blogger.com,1999:blog-8042569099194536366.post6457417810769708411..comments2024-03-28T16:17:52.532+00:00Comments on Captain Bodgit: Hacking 433MHz Remote ControllersSteveDeehttp://www.blogger.com/profile/10645378028590228663noreply@blogger.comBlogger5125tag:blogger.com,1999:blog-8042569099194536366.post-43481336776962050632015-12-22T09:02:41.485+00:002015-12-22T09:02:41.485+00:00Hi Chris, I was using a Velleman receiver to pick ...Hi Chris, I was using a Velleman receiver to pick up the 433MHz radio waves from the PiMote transmitter, which then demodulates (or filters) the signal to retrieve the much lower frequency data stream that contains the on/off series of pulses. It's just like your car radio tuning into the FM band (around 100MHz) and recovering the low frequency audio stream (e.g. music) transmitted by the radio station.<br />If you type "amplitude modulation" into Wikipedia, there is an animated illustration of AM & FM that may help you visualise how this works.<br />Fortunately the data stream from the demodulated PiMote signal is a low enough frequency to allow my sound card to amplify and display it.<br />I hope this helps, but let me know if you need further clarification.SteveDeehttps://www.blogger.com/profile/10645378028590228663noreply@blogger.comtag:blogger.com,1999:blog-8042569099194536366.post-69588117478956748472015-12-21T23:26:29.685+00:002015-12-21T23:26:29.685+00:00Hello! I love your post, but I had a quick questio...Hello! I love your post, but I had a quick question regarding the Sound Card Oscilloscope: Since most audio cards record from 20Hz to 20kHz, how does your SoundCard pickup the 433MHz signal? Wouldn't 433MHz be 433000kHz, well over the limit of the soundcard? <br /><br />Thanks for the awesome resources!Chris Cummingshttps://www.blogger.com/profile/14644571946304218703noreply@blogger.comtag:blogger.com,1999:blog-8042569099194536366.post-36283468171748826752015-10-12T18:48:38.523+01:002015-10-12T18:48:38.523+01:00OK thanks I'll take a look at it again. .OK thanks I'll take a look at it again. .Anonymoushttps://www.blogger.com/profile/07802863590626662012noreply@blogger.comtag:blogger.com,1999:blog-8042569099194536366.post-11908635745373443822015-10-06T18:15:47.463+01:002015-10-06T18:15:47.463+01:00I can't find my original notes, but I think yo...I can't find my original notes, but I think you use the code above for the first channel, and the next code for the second channel. The second channel code probably ends with: 0101 0<br /><br />I hope this helps.SteveDeehttps://www.blogger.com/profile/10645378028590228663noreply@blogger.comtag:blogger.com,1999:blog-8042569099194536366.post-88395668075700137632015-10-05T19:13:47.934+01:002015-10-05T19:13:47.934+01:00Do you know how to make only one relay operate at ...Do you know how to make only one relay operate at a time?Anonymoushttps://www.blogger.com/profile/07802863590626662012noreply@blogger.com