I need help with the design of a two-way 2.4gh comunication board

Other Hardware Product Design
1

I am triying to design a two-way radio module using: 2x E01-ML01DP5 (NRF 24), 2x atmega 328p working at 20Mhz, 2x Neo 6m gps modules, 3x logic level converters, a l1117v33 voltage regulator, some capacitors and resistors.

The problem is: i have tested the setup a few months ago and it worked just fine, i made a schematic to ensure that i build everything the same way next time. But a few days back i build everything in a breadboard the following that diagram and it didnt work.

I check all the conections and they were ok, i tested with resistors in place of the logic level converters (I still have a prototype that work with those) and even soldered some parts in case it was a problem with the breadboards, but that didnt work either.

The only thing that could be wrong are the NRF24 modules, but i tested with 3 different and is bothering me that anyone of those worked, two of then being the ones i used a few months prior.

So i decided to follow the diagrams that i had and design some pcbs (the first ones i design)

pcb upper traces
pcb upper traces1212×603 101 KB

pcb bottom traces
pcb bottom traces1252×630 101 KB

In case it may be the problem these are the logic level converters i am using.

logic_level_converter
logic_level_converter1920×2361 125 KB

So the cuestions i have are:

-are these pcb designs right? would they work?

-what could be wrong with my testing in case the nrf modules were ok

-if the pcbs with the atmega328p work? would it comunicate with and arduino using the same nrf24 type modules working at 16Mhz?

thanks for taking the time to read my problem and sorry for the bad english as it is not my native language

2

is two way radio. so what is the purpose of your project?

3

i want it for rc projects, so switching between the two modes is to slow.

the idea is that one is always sending and the other always receiving

4

Except that putting a receiver so close to a transmiter, on the same frequency (or close) will probably make the receiver go deaf.

Have you tried this simultaneous transmit and receive ?

1 Like
5

not yet, but since you can change the frequency from 2.4ghz till, if i remenber right, almost 2.5ghz;
if i set each one on different ends of that limit it should work well, i supose?

and the addres would be different of course

6

If you could get TX and RF frequencies several Ghz apart that might work, but even then it might not with the respective antennas within a few cm of each other.

But dont design a PCB based on just an idea, build it and test it on a breadboard first !

Do you have much experience with RF devices ?

7

more and less, i tried several things without knowing much, and i had a few prototypes working pretty decent.

the problem is that i am almost sure the "new" modules i have are broken, but i thing is strange that any of then work, considering that is the first time i use one of those three, and the others worked well a few months back

8

did you hear about auto acknowledgement?

9

Is the purpose of full duplex operation for some sort of real time feedback from the model? Can you use both 2.4 GHz and 70 cm radios and achieve the same result?

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no, what it is?

11

yes, is for a full-duplex, what do you mean with the 70 cm radios?

12

A radio that operates in the 70 cm band. A radio band centered on around 428 MHz. The frequency is country specific. That would reduce interference between the two radios.

13

So transmitting at the exact same time as you were also receiving stuff ?

Absolutly sure about that ?

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