Hello, recently I have found a project for Walkie Talkie with Arduino Uno and wanted to try it (Long Range Arduino Based Walkie Talkie using nRF24L01). I am not sure if I should use one Arduino Uno for each Walkie Talkie or I can make one and work with some other. I am still a student and this is my first time exploring project of this size so I am not very experienced either. I know that the project is not from this site but it's the one I liked. If someone can tell me if I should use one or two Arduinos that would be amazing.
"some other" what? Any microprocessor can control the radio.
The project description is a little confusing. The first schematic shown is a prototype using off-the-shelf modules including an Arduino Uno and plug wire breadboards. To build the project this way would require one Uno per "Walkie Talkie" node.
The objective build uses an Atmega328 integrated circuit chip on a custom board which effectively replaces the Uno, so you'd need one one of those per node instead of the Uno.
To program the Atmega328, you'd probably want a (genuine) Arduino Uno with a socketed Atmega328 in a DIP package.
There's a lot involved in this project, so it might not be the best choice of a first project.
Thanks for the advice but I think its to late for me to go for other project because I need this for my school exam and I am already set on it(I think) so I will try to do it.
I have help from my teacher but I though I should ask here as well. So if I can ask one more question.
Can I make one Walkie Talkie and make it work with "professional"(branded) one? Like make it work on the same frequency. I would really appreciate the help a lot and thanks again for the clarifications.
No, aside from the frequency difference, this project is a digital packet radio and commercial walkie talkies are analog.
There is a lot of packet radios used in Amateur radio... So it might be possible to find a commercial type of interface but it will be relatively pricey as the tx/rx operate at 2.5gHz ... you'd need a receiver for that frequency to start with ... $$
The Uno is a 5V board and the tx/rx module is a 3.6V board... the outputs/inputs of the 3.6V board go to the Uno without voltage translation... ?
Good luck with this
For what it is worth, ESP32 can be used too:
That's not great but I think I can make a workaround because my exam is on communication devices. That's why I though of Walkie Talkie first but can't the nrf module transmit any data?
Like if I make it the Uno, module, and hook them to a button and a diode(lamp). Make it work like a Morse code devices that you can press the button on one and the other receives the signal translated into the diode and the person sending it can make the diode light however he wants and the opposite as well
Yes, that will work, but will be really slowwwwww and you will not be able to have any difference in the length of time for a dash. All will be dots.
The NRF has 5V tolerant I/O pins.
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I was actually referring to the 3.6V board communicating with the 5V board....
I know. Same thing applies.
A lot of RF modules can be made to produce a frequency shifted carrier. Shift the carrier frequcny fast enough and you can emulated FM signals that a basic UHF handheld picks us as audio tones, so morse is most definely possible.
I agree. You have to consider two thing, at least:
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Carrier must be continuous (long term) and maintain a long term balance between the number of zeroes and ones. FM does satisfy that.
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Continuous operation on this frequency band is prohibited. This can only be a research project, not for general use.
The very cheap transmitters/receivers could be operated this way, no need for fancy transceiver ICs. You do not need to frequency shift the carrier. Only the payload stream.
So for example, you send a 1000Hz square wave for a "one" and a 1500Hz square wave for a "zero".
Not a good idea. A square wave modulation causes extreme spurious signals. Better stick to sine waves.
The modules are already modulated with non bandwidth limited digital signals. So if it's not a good idea, there are a lot of minds to change.
The modulation method of OOK, on-off keying, is closest to what was asked and they shape the time of carrier rise and fall so there are no "ckicks". All the other methods are modulating the modulation method, ie. AFSK and FSK and phase modulation. They are all processed before getting mixed with the RF carrier.
If the OP wants to use a switch to do something, there needs to be more thought given to how the CW/Morse will be created and sent.
I guess you know, direct OOK modulation (that is, directly keying the transmitter with Morse) won't work in this case because the receiver really has no amplitude discrimination, in the absence of signal the receiver produces noise, not a "zero". You have to send a continuous bit stream to establish the RX AGC level and lock out noise.
Hence I am suggesting sending an OOK bit stream, but the stream consisting of an FM square wave. It is layered. Sure there are many modulation schemes in general, but with these particular modules it is not possible to implement them since they are non-linear in operation and the circuit supports only OOK in actuality.
What I am suggesting could be the very easiest way of sending Morse using these modules. I think that might be important for someone who just wants to complete a first project in communications and get it done before the deadline.
If there is any shaping or signal conditioning in those cheap modules, it is by accident not by design. The transmitter is basically an oscillator that has its power applied and removed to perform the modulation. There is nothing fancy about it. It probably splatters sidebands and junk all over the place, but in the simple key fob remote type applications that it is normally used for, the interference is not considered harmful.
I'm trying to stimulate thoughts about how CW/Morse will be sent, before the OP just throws up their hands and gives up. Although, we haven't heard from them in a while.
Don't know if this will help or not... It's an instructables on Morse for the Arduino...
Oh, please... linking there... come on. And, a keyer has nothing to do with the project as stated..