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You can test the output of a television infrared remote control by photographing it with a digital camera - you see on the image if the infrared LED lights up.

Is there a method, without an oscilloscope, to find out if 27 MHz radio remote control is still sending a signal?

RedGrittyBrick
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erik
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  • I take it that the remote control is the radio-frequency type. Could you put an oscilloscope on the antenna and check to see if there is a signal? – Li-aung Yip Jan 11 '14 at 11:02
  • @Li-aungYip depends on the frequency used and the scope available. I know radio amateurs have their little tricks for this, but I'm not sure how exactly. Similar to [this](http://rookieelectronics.com/sensor-rf-radiation-detector/) but for a different frequency. Erik: What frequency is your RC on? – jippie Jan 11 '14 at 11:23
  • The frequency is 27 MHz. But I don’t have an oscilloscope. I usually use an analog multimeter. Maybe I need an oscilloscope. :-/ – erik Jan 11 '14 at 13:11
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    You can do a lot of electronics without the absolute need of an oscilloscope. You could try the detector circuit I linked to. Remove the LED, replace it with your multimeter. Test it with a known working transmitter. Instead of using a single ended wire, make it a coil with couple turns, 1 or 2 centimeter in diameter. Connect one end to the input capacitor and the other end to the node where the LED cathode was. You need a bit of luck with frequency, capacitors and the coil/antenna. Don't know from the top of my mind how to size them for 27MHz. – jippie Jan 11 '14 at 22:31
  • @Leon Heller please reopen my question. I have reworded it to fit the rules. – erik Feb 11 '14 at 10:22
  • A diode detector would in theory indicate presence of a carrier, but that does not mean the transmitter is functioning correctly. – Chris Stratton Feb 11 '14 at 14:59
  • @erik: Wanna an old school method of determining if you are transmitting or not ? Good thing I am ham radio operator. Tie wrap a small fluorescent light bulb (12 in) at the end of your antenna (assuming 1/4 whip antenna) and key the microphone. The bulb will light brightly in the presence of RF. This is because the voltage is higher at the end of the whip, the current is lower. The RF energy excites the atoms of the gas as well as the phosphor inside the tube. Warning: Do not touch the antenna while transmitting-RF burns are very painful (right up there with putting hand in a microwave) – Old_Fossil Oct 30 '16 at 06:49

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