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About sigmacom
- Birthday 11/01/1976
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DTMF, huh? Good and cheap solution, but too "classic analog" don't you think? I prefer digital; it's more secure... Anyway, I think it's perfect for our friend with the level of knowledge he has. Tips for james120479: - You can ommit the flip-flops (4013) if you don't want to hold the last state (which transmitter was last used). - Forget the 418 MHz receivers we discussed earlier. You must use a simple FM radio receiver instead.
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If you can work with these chips (I say that because of your level of knowledge), then choose an RF transmitter & receiver from http://www.rfsolutions.co.uk/products/rf_modules/Am_fm.htm or http://www.abacom-tech.com/receivers.htm and http://www.abacom-tech.com/transmitters.htm Some of them are really cheap for you I suppose... Any questions? :)
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I agree with this: "Solid State in my mind means not mechanical" but the schematic, can't be called "a solid state relay": As you know, relays offer isolation between the relay contacts and the coil. Also, you can control (on-off) any kind of voltages/currents, with indepedent voltage on coil. A solid state relay (the component, not substitutes) does all this, because it has a diode as coil, and photosensitive thyristors/triacs as relay contacts (for example, with 5VDC as control voltage, you can do 220VAC on-off control). None of the above conditions met by the schematic posted above, so I couldn't call it "a solid state relay". Anyway, it does it's job! ;)
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Yes, but this is not a solid state relay, as the title of this thread says... ??? ???
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Is it mandatory to use 74ls283 and 74ls194?
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A very simple approach, is shown in the following schematic. The 2 resistors of 1 kOhm each, make a voltage divider /2, providing a Vcc/2 voltage to the (+) pin of the comparator. This is used to set the (+) input at higher voltage vs the (-) input -and so- force the output (Y) to high state (Vcc). When voltage at pin (-) of comparator goes more than Vcc/2, then the output of the comparator (Y) goes at low state (GND) and vice versa. If you ommit the resistors, the input voltage at pin (-) must be > Vcc to trigger the output. Try it! :D
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Also notice that most common solid state relays, are made to handle ONLY RESISTIVE LOADS, not inductive (like as a motor). Else they burn... There are specific type of solid state relays to handle that kind of loads. Seek for them. :)