Help in deciding method for de-modulating? a signal to extract one frequency!

[Benny7440]

Maybe, it's not clear enough! For years I've been thinking of designing & build a remote controlled sailing-motorized boat & controller. This means that the boat itself should be made by me as well as the receiver at the boat.

I've been thinking of using a recorder (the musical instrument) as the sending apparatus. The problem is how to deal with the signal at boats' end. From here comes the term in the title --modulation, which strictly speaking doesn't apply.

I've been reading electronics books for a couple of months to see if there was something useful & at least tangent to this but without luck. Today read one of your newsletters that contained an article about past (remote) magazines and wondered if you might know of a few articles in some of them pertaining to the present topic.

Yes, I could ask for precise solutions as circuit designs made for this but I prefer, for now, to make this a search & discover issue. There's a lot to discover when you search like this instead of like asking Alexa!!!

Thaks in advanced for any help on finding my bearings!

 

[BobK]

There are two general methods you could use, one analog and the other digital.

The analog solution involves a set of bandpass filters, one for each frequency, and each followed by a peak detector.

The digital solution would involve some form of Fourier transform.

Bob

 

[kellys_eye]

Fairly 'tight' filters can be made using dedicated tone decoder IC's such as the NE567. Your problem would be 'interference' from anyone simply whistling! and taking control of your model boat..... bye bye boat.

http://pdf1.alldatasheet.com/datasheet-pdf/view/17983/PHILIPS/NE567.html

If interference from outside sources isn't considered a problem (sailing in a private location for example) then you might be able to adopt a techinique using dual-tone techniques as used on telephone keypads. Tone generation and decoding chips for this purpose are quite common although whther you could emulate them using a recorder is something you'd have to investigate yourself.

 

[duke37]

Bagpipes will give a multiple drone which could be used as a security device.
You may need a large output power to get the sensitivity.

 

[(*steve*)]

Finally an application for electronic bagpipes that doesn't pretend to be about music!

 

[kellys_eye]

Bagpipes will give a multiple drone which could be used as a security device.
You may need a large output power to get the sensitivity.

...and you'll DEFINITELY be sailing the boat alone.......

 

[dorke]

Benny,
Are you trying to reinvent the wheel(Helm) here?
There so many commercial remote controllers available...

 

[davenn]

Maybe, it's not clear enough! For years I've been thinking of designing & build a remote controlled sailing-motorized boat & controller. This means that the boat itself should be made by me as well as the receiver at the boat.

I've been thinking of using a recorder (the musical instrument) as the sending apparatus. The problem is how to deal with the signal at boats' end. From here comes the term in the title --modulation, which strictly speaking doesn't apply.

so you want to remote control using sound

you realise that isn't going to work for more than a few feet ?

Benny,
Are you trying to reinvent the wheel(Helm) here?
There so many commercial remote controllers available...

indeed

you need to be using radio control. you need multiple channels/codes to control the various 'things on the boat
1 for sails, another for rudder etc etc

you cannot do this with a single freq sound signal ... even if the operational distance thing I mentioned above wasn't an issue


Dave

 

[davenn]

Yes, I could ask for precise solutions as circuit designs made for this but I prefer, for now, to make this a search & discover issue. There's a lot to discover when you search like this instead of like asking Alexa!!!

It is time to reconsider your path in the light of previous comments by all of us here and you will see that buying various modules
and getting them operating together will probably be as much as you may be able to handle, without even thinking
of building from scratch your on transmit and receive units


Dave

 

[duke37]

Use a sheep dog for reception, distances of up to a kilometer should be possible, either using voice or whistle.

Have you looked at the purity of a recorder tone. Even if there are many harmonics, three of four notes could be discerned within one octave. Early model control used tuned filters, I made one with two filters to switch a water pump on and off using a radio link.