I thought that was just because it was being used as an IR transmitter. The crystal setting the precise frequency. Well that does clear things up a bit :lol:i think your chip doesn't oscillate. you wired it like HT12E instead of HT12A. so change the resistor from 47k to value shown, add crystal and two capacitors. that should do it...
shame on you for making me look it up..
it says that HT12A runs on 5 v not six..
zachtheterrible said:Alrighty than. I tried a 3.5MHZ crystal, a 10M resistor, and two 150pf capacitors in the oscillator section. No results whatsoever.
What value of crystal would be preferrable? I get the feeling that 3.5MHZ is much too high. Unfortunately I don't have any lower value crystals.
Without the 10M resistor and 150pf caps, I can get a small 3.5MHZ sine wave out of the DOUT pin on the HT12A after closing D8.
I'm very quite lost here. Please help
Nigel Goodwin said:3.5MHz is too high - IR remote controls commonly run from 455KHz crystals,
3 6 2
020-1
zachtheterrible said:I tried using the HT12D as well. The oscillators are oscillating at very close to the same frequency as each other.
oh dear, theres my problem :lol: . I skipped right over that. Sort of a funny place to put such an important thing.The data sheet of HT12D specifically mentioned that OSC freqiency of decoder should be 1/3 that of HT12A encoder.
I don't think so but ill make sure of that. The waveforms looked the same on my oscilloscope. Of course I couldn't compare them right next to each other because I only have one probe for now.As a quick thought, you've left all the address lines floating, I don't know what effect that might have, but there's certainly a chance that this may result in them both being set to different addresses.
Yes, the input is negative, the output is positive.Also, is the input the same polarity as the output?, they are intended for IR remote control, and the remote receivers invert the data.
zachtheterrible said:oh dear, theres my problem :lol: . I skipped right over that. Sort of a funny place to put such an important thing.
nah... you just know what to skip... :lol:
zachtheterrible said:One thing that I noticed is that the output of the HT12A does not oscillate as fast as the actual oscillator (X1 and X2). I did not bother to measure the frequency. Am I supposed to make the oscillator frequency of the HT12D 1/3 of the output of the HT12A or the oscillator of the HT12A?
I am still not getting any kind of output from the HT12D. I think im doing everything right here.
I am now connecting them via a 433MHZ tx and rx so they are not connected directly now.I thought we'd already decided that the input of the HT12D is inverted with respect to the HT12A? - so connecting them directly wouldn't work?.
Also, if it's IR, it's modulated on a 38/40KHz carrier - the receiver requires the data, NOT the carrier - an IR receiver IC strips the carrier off, and provides the correct polarity inverted data.
zachtheterrible said:Now I realize that the HT12A is meant for infrared and it doesn't seem like it works very well with the HT12D.
zachtheterrible said:Ah well, live and learn :roll: .
zachtheterrible said:Im gonna go ahead and buy the HT12E.
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