Bluetooth or another technology for this little project ?

Thread Starter

dyn_o

Joined May 29, 2017
35
Hy,

I have to use RF communication in a project but I don't know which technology to choose.

Here is the project :

It is composed of 4 PCBs. They are placed 10 cm from each other in line so a 1 meter line of 4 PCBs. The PCBs communicate with each other in a local network. No Internet involved.

We push a button in PCB4 (the master) and a request is sent to PCB1 (slave) to send DATA1 to PCB4. PCB4 receive data and send it back to PCB1. PCB1 compares the received data with DATA1 sent before. If they are equal, PCB1 send "OK" to PCB4. If they are not, PCB1 send DATA1 one more time, then we got the same checking process. 10 times retransmission if not OK until stop.

When PCB4 receives OK, it send a request to PCB1 to send DATA2, and so forth until DATA8.

When PCB4 receive the last "OK", it send a request to PCB2 (another slave) to send DATA9. Then same process until DATA16.

Then PCB4 send a request to PCB3 (another slave) to send DATA24, et cetera until DATA32.

My first idea was to use nRF24L01 but I think Bluetooth is easier and I prefer non proprietary protocol. I really don't have much knowledge in RF communication. I thought about zigbee and xbee but I think it is inappropriate. My idea is to use bluetooth modules like HC-05 and HC-06. They would be connected to microcontroller in each PCBs.

Could you tell me if I'm right choosing bluetooth and these modules for this little project ? I want to keep it simple.

Thanks
 

Thread Starter

dyn_o

Joined May 29, 2017
35
Thanks Dana for your answer. The thing is I want to keep it simple and to make it work in 1 or 2 days because I have lot of other things to do. PSoC will take me too much time to learn. That is why I asked if HC-05 and HC-06 could do the job.
 

LesJones

Joined Jan 8, 2017
2,316
You could use HC-12 modules. These are 433 Mhz transmitter / receiver modules that send and receive serial data. You would have to design a protocol that send the address of the destination module. These modules are listening on the frequency so they will all hear the transmission so the microcontroller on each PCB will have to recognise it's address. The problem you may have is reducing the signal level between them by using a dummy load (Resistor) instead of the normal antenna as they are so close together. I don't understand your statement "They are placed 10 cm from each other in line so a 1 meter line of 4 PCBs." If there are 4 PCBs in a line spaced 10cm apart then the distance between the two end ones will be 30 cm.
Is the homework or a school project ?

Les.
 

Thread Starter

dyn_o

Joined May 29, 2017
35
You could use HC-12 modules. These are 433 Mhz transmitter / receiver modules that send and receive serial data.
I don't need to send at 1km so why use HC-12 instead of HC-05 and HC-06 ?

You would have to design a protocol that send the address of the destination module. These modules are listening on the frequency so they will all hear the transmission so the microcontroller on each PCB will have to recognise it's address.
Ok.

I don't understand your statement "They are placed 10 cm from each other in line so a 1 meter line of 4 PCBs." If there are 4 PCBs in a line spaced 10cm apart then the distance between the two end ones will be 30 cm.
Mmmm, I was not clear. i just wanted to say that from the extreme left to the extreme right there is maximum 1 meter. Don't mind the distance between the PCBs and the size of the PCBs.

Is the homework or a school project ?
This is part of a school project.
 

LesJones

Joined Jan 8, 2017
2,316
As far as I know Bluetooth (HC-05 and HC-06) only works in a master / slave system so I think it would be difficult to get all the PCBs into a network. Other members will probably say if my understanding of Bluetooth configurations is right or wrong.

Les.
 

Thread Starter

dyn_o

Joined May 29, 2017
35
As far as I know Bluetooth (HC-05 and HC-06) only works in a master / slave system so I think it would be difficult to get all the PCBs into a network. Other members will probably say if my understanding of Bluetooth configurations is right or wrong.

Les.
HC-05 can be master and slave, HC-06 in only slave. As my slave PCBs never act as masters I could use HC-06 for them, or just use HC-05 for all the PCBs. In a bluetooth network (called piconet) a master can communicates with 7 slaves. So it is OK for my system of 1 master and 3 slaves.
 
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