Wireless remote switch, button press: 1 second=ON, 3 seconds=OFF

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[[File: LTspice_V1_bluePress8seconds_blue_givesON-OFF_7v_outputs.png]]
 
[[File: LTspice_V1_bluePress8seconds_blue_givesON-OFF_7v_outputs.png]]
  
I tried to omit the 3H inductor and I ran into a small problem with the data being vdc. The inductor converts it to AC. I think a large serial capacitor would work instead, but then maybe it cannot be a polarised type. I stopped thinking about it since I have an old small power adapter transformer to use as 3H inductor.
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I tried to omit the 3H inductor and I ran into a small problem with the data being vdc. The inductor converts it to AC. I think a large serial capacitor would work instead of an inductor, but then maybe it cannot be a polarised type of capacitor. On the other hand, a smaller serial ceramic capacitor would work with a mosfet gate, instead of a transistor base (smaller current). I stopped thinking about it since I have an old small power adapter transformer to use as 3H inductor and it works.

Revision as of 11:22, 3 October 2016

I bought a 315Mhz transmitter/receiver pair of postage stamp size boards from robotshop.com. Ebay has them too.

Here is the schematic of how I used the data output of the receiver. The objective is to process the data without using a digital serial interface processor and to latch the ON and OFF so they do not spuriously switch back and forth from neighborhood transmissions on the same frequency, from electrical lightning noise, nor from button-bounce:

315Mhz schematic.png

Here is the board layout, which should be redone in surface mount parts some day. I used drawer junk parts and old VCR parts: 315Mhz wireless remote-switch 120vac-off-on.png

Here is the LTspice simulation of the signal filter of data incoming ON and OFF button presses. This 2Hz to 12000Hz response curve shows 60Hz is near the peak response: LTspice of data input filter 2Hz-12000Hz.png

After the diode and 47uf capacitor, the signal is 0.7vdc with some ripple. High frequency data would not get through, and neither will lightning pulses. I have a commercial remote switch that was triggered ON by lightning and that is not acceptable, thus my filter idea using 60Hz pulses. LTspice 60Hz for 1second goes through to Q2 as 0.7vdc.png

Here is LTspice of the 1s and 3s hold-for-OFF using pulses from V1 which is imitating the 60Hz converted to 0.7vdc from the previous LTspice. See 3 second delayed OFF and instant-ON effect in green. Blue is the button held down for 8 seconds each time: LTspice V1 bluePress8seconds blue givesON-OFF 7v outputs.png

I tried to omit the 3H inductor and I ran into a small problem with the data being vdc. The inductor converts it to AC. I think a large serial capacitor would work instead of an inductor, but then maybe it cannot be a polarised type of capacitor. On the other hand, a smaller serial ceramic capacitor would work with a mosfet gate, instead of a transistor base (smaller current). I stopped thinking about it since I have an old small power adapter transformer to use as 3H inductor and it works.

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