Hi! I would like to have an LED indicator of whether a pressure sensor is being pressed or not. However, I would like the pressure sensor and the LED to be wirelessly connected somehow (the sensor and the LED will be 2 meters away from each other). How can I achieve this with the least amount of materials possible? Any ideas will be appreciated!

 

If the sensor and the LED locations have line of sight between them then the simplest might be to use an IR LED/photo-transistor combination to send the signal. Otherwise the 433MHz TX/RX modules combination (many on ebay) would do the trick.

 

Hi! I would like to have an LED indicator of whether a pressure sensor is being pressed or not. However, I would like the pressure sensor and the LED to be wirelessly connected somehow (the sensor and the LED will be 2 meters away from each other). How can I achieve this with the least amount of materials possible? Any ideas will be appreciated!

Not sure what you mean as to a pressure sensor being pressed? Pressure sensors sense pressure. Did you want to read an analog or digital (yes/no) signal. If this is simply a button being pressed there are dozens of key fob relay cards which could be modified. A key fob example is the key less entry used on many automobiles. Another example is a wireless doorbell. There are also wireless transmitter / receiver combinations for sending and receiving analog signals so it depends on exactly what you want and the signal is.

Ron

 

If the sensor and the LED locations have line of sight between them then the simplest might be to use an IR LED/photo-transistor combination to send the signal. Otherwise the 433MHz TX/RX modules combination (many on ebay) would do the trick.

Thank you for your help! There will most likely be something in between the LED and the sensor, so I guess I should be looking into the TX/RX modules!

 

Same question I had in my post #3. What type signal are you looking to transmit? Analog or a digital signal.

Ron

 

Same question I had in my post #3. What type signal are you looking to transmit? Analog or a digital signal.

Ron

Hi Ron,
Thank you for your help as well! I have actually been reading on how key fob relay cards work since I saw your reply. The signal that is intended to be transmitted is a digital yes/no signal, but since I am using a pressure sensor I'm imagining the direct output to be analog, and then I will set a threshold to define what is a yes or a no. Also, I would like to have my device to work on airplanes as well, so I assume I should look into the frequency ranges so they don't interfere with other important signals on the plane. Should that be a concern?

 

Hi Ron,
Also, I would like to have my device to work on airplanes as well, so I assume I should look into the frequency ranges so they don't interfere with other important signals on the plane. Should that be a concern?

Yes, but also they may object to home-made things with wires and battery.

 

Also, I would like to have my device to work on airplanes as well, so I assume I should look into the frequency ranges so they don't interfere with other important signals on the plane. Should that be a concern?

In my opinion yes, that should be a primary concern especially when looking international. Currently in the US for example the use of mobile phones (cellular phones) is a hot topic issue. I am sure other countries have rules governing the use of radio transmitting type devices. So that may be a concern.

Transmitting a yes/no should not be a problem. Generally when an analog signal crosses a threshold it can be detected using a comparator circuit or similar. Matter of deciding what should happen at that point. Should something "latch" requiring a manual reset or should reset be automatic when the signal level drops. Voltage comparators in this forum learning series may help. I would look further at simple single channel (assuming you only need one channel) key fob relay cards. Here are some examples. They have become very inexpensive and a transistor could likely easily be used to bypass the key fob button driven by the comparator I mentioned.

Ron

 

Yes, but also they may object to home-made things with wires and battery.

Actually a very good point.

Ron

 

Thank you Ron and Albert for your insights! I understand that having home-made electrical gadgets on flights may face many restrictions, but I am only in the prototyping stage and would like to have something that theoretically works and conforms to standards. Ron - I am looking for an automatic reset when the voltage level drops. I will read about the voltage comparator now.

Thanks again!

 

Ron - I am looking for an automatic reset when the voltage level drops. I will read about the voltage comparator now.

OK, so I would start with a voltage comparator, like I linked to. You start with some signal conditioning and run your signal into a voltage comparator in which you set a threshold. When your analog signal exceeds a preset threshold that triggers your transmitter which will transmit for the duration you exceed your threshold level. That is how I would likely go about it, other members may have some thoughts.

Ron