Radio controlled lighting by using VHF PTT

Thread Starter

Edvin Ferkic

Joined May 28, 2019
11
Hi, I am starting on a project, and I would like to get some help to start with this or get some tips on how to start and where. This is very similar to a so called Pilot-controlled lighting system or PCL but I would like to build and use at home, not for industrial or commercial use and also I would like to use the latest technology to build it.

So the purpose of this design is to use VHF radio (Icom or similar), Use its Push-To-Talk (PTT) button to send signals to a receiver of some kind and get those signals to a controller board which again registers the signals and by some programming/setup it switches on a relay board connected to it to turn on or off the lights.

This means I need an airband (118-136 Mhz) receiver of some brand, can also just be an airband board but with desired frequencies. I need a controller board or a small computer like raspberry pi, beaglebone or arduino uno to use as a controller, and I need an a compatible relay board that can swith on or off some light bulbs (60W-120W) connected to it.

My questions are:

1. Is there any tips on how to do this?
2. What about any previous home projects?
3. Has anybody attempted this before?
4. Can raspberry pi or arduino be used for this? If so, which one is recommended?
5. Do I maybe need an SDR Software-defined-radio for this?
6. Is it possible to just buy an cheap airband receiver board?



Thanks
Edvin
 

Externet

Joined Nov 29, 2005
1,534
Hi.
1. A PTT action counter using a shifter IC can trigger the desired relay.
3. I played with it for a while.
4. I see no reason why not.
5. I do not like SDR because have volatile memory as far as I found.
6. I have a couple of kits, one assembled, one not
 

Thread Starter

Edvin Ferkic

Joined May 28, 2019
11
Ok, so this PTT action counter using a shifter IC can trigger the desired relay. What is it made of? Is it an custom circuit or can you use like an arduino for that?
 

Externet

Joined Nov 29, 2005
1,534
Every PTT action sensed can feed a low or a high signal to a counting IC and a chosen output pin will trigger a relay for the number of PTT events selected. Seen it done with 74HC595.
Instead, an Arduino could do the sensing, counting, timing and resetting.
 

Thread Starter

Edvin Ferkic

Joined May 28, 2019
11
Yes thats true, I will be using Arduino for this so I got this covered. My next goal is get a receiver which is needed to get the transmission, then connect a Arduino to it and do the needed steps in order to capture and maintain those low or high signals. Which Arduino do you recommend? Uno? Or something lighter than that?
 

Wolframore

Joined Jan 21, 2019
1,785
Uno is pretty light but this can easily be done with much less (such as an ATTINY module)... in fact you could skip the arduino completely if you want. You won't save much by going smaller unless you make these in serious volume and Uno is easier. Try a nano you pretty much get a uno in a smaller package. What are you using to transmit and receive? If you just need a simple radio try a nfr24L01. They are simple, inexpensive and work at 433 MHz. They are limited range which can be improved with better antennas, again these are simple no encryption or any other bells and whistles. I'm not sure about your use of 118-136 bands, I believe those are restricted... plus the antenna requirements get larger.
 

Externet

Joined Nov 29, 2005
1,534
Cannot suggest a microcontroller, use whatever you are familiar with. I have two digital display receivers, one already modified for the ~108-136 band, the other stock for the 3 metre band in kit form. There is no 'restricted' reception on 108-136MHz.
 

MisterBill2

Joined Jan 23, 2018
6,992
First of all, you are talking about transmitting in the aircraft communications frequency band without a license. I predict LOTS of trouble with the federal authorities if you do that.There are quite a few legal radio control frequencies available that do not even require a license.
Next, to gain a bit of flexibility, use a DTMF encoder with the transmitter and a DTMF Decoder with the receiver. That will immediately give you 12 command functions with available modules. Two years ago I purchased 3 of the decoder modules for about $3 each. For the transmitter and receiver you could buy a cheap, audio only, baby monitor set and just re-package it.
 

Thread Starter

Edvin Ferkic

Joined May 28, 2019
11
Uno is pretty light but this can easily be done with much less (such as an ATTINY module)... in fact you could skip the arduino completely if you want. You won't save much by going smaller unless you make these in serious volume and Uno is easier. Try a nano you pretty much get a uno in a smaller package. What are you using to transmit and receive? If you just need a simple radio try a nfr24L01. They are simple, inexpensive and work at 433 MHz. They are limited range which can be improved with better antennas, again these are simple no encryption or any other bells and whistles. I'm not sure about your use of 118-136 bands, I believe those are restricted... plus the antenna requirements get larger.
I am not going to transmit anything on the airband frequency, All I want is to test my project at the airband frequency range by just keying the PTT and control some relays using arduino and relay shield. A couple of clicks is just needed, I am not going to transmit anything, I am allowed to listen in the airband frequency and that is not restricted. I will check my local athorities anyway what specific frequency I can use, everything is local. I can even use higher frequencies of 430+ Mhz just for testing purposes.

I haven't decided yet which transmitter and receiver to use. Probably something very cheap and which I can get those PTT signals from. I haven't got a clue which brand is good and which is better, but at least something capable of doing the job quite ok. I also considered buying an airband receiver board and hook that up to my Arduino, there is boards out there which an specifically designed for scanning and listening on the airband frequency without actually buying an expensive transciever.
 
Last edited:

Thread Starter

Edvin Ferkic

Joined May 28, 2019
11
Cannot suggest a microcontroller, use whatever you are familiar with. I have two digital display receivers, one already modified for the ~108-136 band, the other stock for the 3 metre band in kit form. There is no 'restricted' reception on 108-136MHz.
I will be using an UNO, a final decision is made to use this one, even though an Nano can be used.
 

Thread Starter

Edvin Ferkic

Joined May 28, 2019
11
First of all, you are talking about transmitting in the aircraft communications frequency band without a license. I predict LOTS of trouble with the federal authorities if you do that.There are quite a few legal radio control frequencies available that do not even require a license.
Next, to gain a bit of flexibility, use a DTMF encoder with the transmitter and a DTMF Decoder with the receiver. That will immediately give you 12 command functions with available modules. Two years ago I purchased 3 of the decoder modules for about $3 each. For the transmitter and receiver you could buy a cheap, audio only, baby monitor set and just re-package it.
I don't need an license to do some clicking on a PTT button quite fast. not going to transmit my voice, and for listening its completely allowed. Will check my local athorities anyway just to make sure.
Yes an DTMF encoder/decoder is someting I consider using, but will try without DTMF first. DTMF is an interesting and easier approuch to do this.
 

Externet

Joined Nov 29, 2005
1,534
Hi.
Let me know when you are done implementing it with any microcontroller; perhaps I can buy a couple from you.
Does not matter if the PTT count is from a 'low' or a 'high' carrier presence signal. A jumper could select which to use for a particular Rx.
It would be good to reset the counter to zero after 2? seconds of no PTT. The 'normal' PTT count I have seen for 3 relays brightness is 3=25%; 5=50%; 7=100%
 

Wolframore

Joined Jan 21, 2019
1,785
Sounds like there are a few requirements

I see that there’s no transmission from this controller so there are no restrictions for FCC or similar

first we need to identify the squelch break so they can be registered as
the code will count and keep track of a time out period (5 sec) if 3-5 pulses are not sent.
certain number of pulses within a timeout period would register as commands

question is how to distinguish 3-5-7 breaks, will it wait for time out (5sec) to register?

then it starts a timer for lights on and activate relay(s) timer set for 15 min

if the start commands happens before time out, timer is reset.

after time out relays are shut off and waits for next commands

it’s pretty straightforward, the coding should be pretty easy, not sure what The breaks look like and how they will be registered, perhaps a Schmitt trigger based on on and off.
 

MisterBill2

Joined Jan 23, 2018
6,992
One thing that you do need to be aware of is that in the VHF spectrum there are still noise bursts that will break the squelch. As a licensed ham operator I use the 146 Mhz band and observe that there are noise bursts that get through even an FM receiver and break the squelch. This means that to prevent random triggering you will need to have additional encoding of some kind, and matching decoding on the receive end. So suddenly the project gets a bit more complex.
 

Reloadron

Joined Jan 15, 2015
5,646
How much distance are you talking about? How many channels do you plan to use? If either of those was mentioned I missed it.
get those signals to a controller board which again registers the signals and by some programming/setup it switches on a relay board connected to it to turn on or off the lights.
Your objective can be accomplished easily depending on distance and if you only need a few channels (relays) very easy over a short distance. Inside of 100 feet a simple cheap 4 channel relay card will work. There is no need for a uC (micro-Controller) like an Arduino or similar.

Ron
 

Thread Starter

Edvin Ferkic

Joined May 28, 2019
11
Sounds like there are a few requirements

I see that there’s no transmission from this controller so there are no restrictions for FCC or similar

first we need to identify the squelch break so they can be registered as
the code will count and keep track of a time out period (5 sec) if 3-5 pulses are not sent.
certain number of pulses within a timeout period would register as commands

question is how to distinguish 3-5-7 breaks, will it wait for time out (5sec) to register?

then it starts a timer for lights on and activate relay(s) timer set for 15 min

if the start commands happens before time out, timer is reset.

after time out relays are shut off and waits for next commands

it’s pretty straightforward, the coding should be pretty easy, not sure what The breaks look like and how they will be registered, perhaps a Schmitt trigger based on on and off.
Yes, you read my mind Wolframore :) This is exactly what I am planning to do. I am planning to use an arduino, a receiver, a transmitter and a relay board, maybe a DTMF and some coding. What else do I need to achieve this?
 

Thread Starter

Edvin Ferkic

Joined May 28, 2019
11
How much distance are you talking about? How many channels do you plan to use? If either of those was mentioned I missed it.


Your objective can be accomplished easily depending on distance and if you only need a few channels (relays) very easy over a short distance. Inside of 100 feet a simple cheap 4 channel relay card will work. There is no need for a uC (micro-Controller) like an Arduino or similar.

Ron
My distance to test is about 30 miles coverage area with a minimum height of 700ft, so I will need an antenna for this. You can PM me with more details about how you think this can be accomplished without an micro-controller.
 

MisterBill2

Joined Jan 23, 2018
6,992
How much distance are you talking about? How many channels do you plan to use?
My distance to test is about 30 miles coverage area with a minimum height of 700ft, so I will need an antenna for this.
OK, now there is some actual number attached to the discussion. In addition, the signal is transmitted from some sort of aircraft. The potential for interfering with others is real, and the application is clearly in a realm that is regulated. To avoid causing problems it seems like the thing should shift to a CB radio channel and add a DTMF string to enable the control command operation. Note that in addition to the 40 voice channels CB also includes five radio control channels. I suggest CB channel "A", located between voice channels 4 and 5. USE FM and a DTMF string and you will never be noticed or bothered, and you will be legal.
 

Wolframore

Joined Jan 21, 2019
1,785
I see no legality issue in this application, pilots will be using licensed radios, there must be channels that are assigned to this specific use. The challenge is designing and building a reliable system that is sufficiently hardened.
 
Top