Synchronizing two devices with an RF signal

[Borek]

I need two synchronously flashing LEDS (as if they were connected together), but if possible I prefer to avoid connecting them with a wire. No problem with each one having its own battery and a driver. They will be about 2m apart without anything that could stop RF in between. I find it hard to believe there are no ready simple and cheap systems that can be used for such applications, but I am either using incorrect terms when googling, or what I am looking for is buried under other, unrelated systems.

Any suggestions what to look for, or what are correct googling terms?

 

[.Scott]

Any suggestions what to look for, or what are correct googling terms?

I looked under "remote control" and found this:
https://www.adafruit.com/product/13...xm_eRceblPEJ_RVBLy1kQa_cFatgaCfRoCt4sQAvD_BwE

And the receiver:
https://www.adafruit.com/product/1097

 

[Tom.G]

A photocell on the slave. Can also modulate the master and bandpass the slave amplifier if needed.
Garage door remote and receiver.
TV remote and receiver. (IR or ultrasonic)

 

[CWatters]

I looked under "remote control" and found this:
https://www.adafruit.com/product/13...xm_eRceblPEJ_RVBLy1kQa_cFatgaCfRoCt4sQAvD_BwE

And the receiver:
https://www.adafruit.com/product/1097

I think you need the M4 momentary type rather than the toggle type?. If you have the toggle type the reciever could potentially get out of step with the master.

 

[Averagesupernova]

A photocell on the slave. Can also modulate the master and bandpass the slave amplifier if needed.
Garage door remote and receiver.
TV remote and receiver. (IR or ultrasonic)

I was thinking something similar. At a range of 2 meters I would not consider anything other than optical.
-
@Borek is there a reason why photocells or phototransistors could not be used? Will there be a barrier between at times?

 

[Borek]

Sorry guys, I was (and am) busy with other things, but I have read everything you posted.

LEDs will be on the wings of the RC plane - so I can't guarantee they will both see each other (fuselage in between), construction is not exactly rigid, and they will be mounted using velcro. It all makes me doubt IR and photocell solutions will work, as the line of sight can be obscured and I can't guarantee directionality of the LED and photocell (and I assume it is necessary). I have nice lights on other model, controlled with Arduino and whatnot, but this time I need an easily removable solution that can be used on any model.

I have a chest strap-based heart rate monitor that apparently communicates with the handlebar mounted display using a radio. I believe all the chest sensor does is it is sending a pulse for each heart beat, this is more or less kind of a solution I was thinking about (and would be satisfactory). (Actually if you can suggest what frequency it can use I could try to check if that's how it works using RTL-SDR scanner).

Yes, there is a potential problem with LEDs getting out of synch if the pulse is used just for toggling the state. At the same time if I am able to just make them start the pulse at the same time and use 555 to keep the pulse length mostly identical on both wings it should be enough.

They will never work for longer than about 30 minutes

I will look into remotes.

 

[Tom.G]

https://www.google.com/search?&q=super+regenerative+receiver+315MHz
At least some of the hits are for receive-transmit pairs starting at $6.

 

[rbelli1]

You could use something like: https://www.dfrobot.com/product-155...ilQEBtXs6bcEQUNMYFXJ903TMLbgx6yBoCLKcQAvD_BwE too. It is a distressingly complex solution to your problem but you also get the ability to control the lights from your phone.

BoB

 

[Baluncore]

433 MHz data links work well.

You might put a LED on the Rx with a driver MOSFET, with the transmitter in parallel with the controlled LED.

Or transmit control from the body, to two LEDs each with a Receiver on the same frequency.

https://www.ebay.com.au/itm/433Mhz-WL-RF-Transmitter-Receiver-Link-Kit-Module-for-Arduino-ARM-MCU-Wireless/223109707057?hash=item33f25ff531:g:f3wAAOSw44BYFvYw:rk:12:pf:0