What is your good/bad experience in mesh/tree ?

Projects Networking, Protocols, and Devices
1

Dear
I’m a newbie, Guillaume, based nears Nantes in France; Excuse me for the simplicity of the following question.

After reading some articles/threads about modules to communicate (star, tree, mesh,etc.) in 2.4 or 868 or 433, with some modules like : Xbee by Digi, Pinnoc.io, nRF24L01, etc. It’s seem to me it’s really difficult (with lot of problems hidden in module datasheet/specification) to finish a project with reliability in generic case (outdoor, indoor (mall, train station, subway, airport, etc.).)

So, my question is : for you what is the best way or simply your experience (good or not) to realize a mesh or tree with reliability in term of communication (ie without frame lost) with the minimum of work (ie without to control ack, etc.), and low power…

Best regards for all.

2

So, my question is : for you what is the best way or simply your experience (good or not) to realize a mesh or tree with reliability in term of communication (ie without frame lost) with the minimum of work (ie without to control ack, etc.), and low power…

You will never achieve 100% packet transmission reliability.

XBees have built in microprocessors that handle acknowledgement and retransmission for you. The cheap radios do not.

Indoors or outdoors? How far? How many radios? How much data? How often? What definition of low power? Details matter.

3

This topic is dedicated to read your experience.
In order to realize my project, details following:

How far?
Indoor : like mall, around 50m to 100m ideally
Outdoor: like train/bus station, airport, ideally up to 200m.

How many radios?
network up to 100 nodes.

How much data?
around 500 Bytes if compressed each 1mn.

How often?
every 1mn to 5mn

What definition of low power?
Ideally
40mA Tx
20mA Rx
Sleep 2uA

Details
each nodes contain a sensor like maxsonar and send to cloud theses measurment every 1 or 5mn.

4

PaulS:
XBees have built in microprocessors that handle acknowledgement and retransmission for you. The cheap radios do not.

Then if what you say is true what is Enhanced Shockburst feature of the cheap NRF24L01+ radios?

From the data sheet..

7.1 Features
The main features of Enhanced ShockBurst™ are:
• 1 to 32 bytes dynamic payload length
• Automatic packet handling
• Automatic packet transaction handling
Auto Acknowledgement with payload
Auto retransmit
• 6 data pipe MultiCeiver™ for 1:6 star networks

That appears to me to be saying they(the cheap radios) are handling acknowledgement and retransmission for you.

5

Dear Frostline,
thanks a lot, for your message. In return, do you some restriction about ratio betweenn nodes and master ? or other physical ratio ? It seems to me there exists, dual headed operation detailled here
http://tmrh20.github.io/RF24Network_Dev/Tuning.html
in which case, there duality much be used ?
Also, do you know some link in order realize and test, for example 5 nodes and 1 master.
Also why you do not talk about digi product like Xbee 2.4 or 868 ? it's for the price/cost or because it's not fully documented, or it's not reliable ?
Best regards.