How far does the mesh stretch?

[alowhum]

What is the maximum amount of hops people have been able to reach? Is there a theoretical limit?

For example, let's say there's a big construction project over the length of a street, and a group of people there together wanted to measure all kinds of things.

• Neighbour 1 has an air quality sensor on their balcony
• The next neighbour has a vibration sensor on their windowsill
• The next neighbour has a dust sensor on their balcony
• The next neighbour has a noise level sensor on their balcony, and a seismic sensor in their basement.
• Etc.

All of them would be repeaters.

How many hops could that realistically go, while still having the one central data storage gathering point?

[mfalkvidd]

@alowhum MySensors is not a mesh. MySensors uses a tree topology.

The theoretical limit for the number of hops between a node and the gateway is SIZE_ROUTES which is 256 hops.

[alowhum]

Thanks, good point on the mesh. I considered the 'auto routing around issues' functionality to be a bit mesh-like, but you're right, there is a central point.

While 256 is great in theory, what is the maximum number of hops people have reached in practice?

[sundberg84]

@alowhum any normal user should be good with node > repeater > gw . Atleast that's my maximum.

But I guess you could test by building some repeaters with forced node and parent id.

[gohan]

A larger topology would most likely have high latency, messages could get lost and need to be resent more often than usual small network

[alowhum]

@gohan That's what I thought as well. But I don't know: how bad is it?

@sundberg84 Sure, I could test it. But I'm here to ask if anyone else already has :-)

[CrankyCoder]

I would be really interested to see this put in practice. For stuff like those sensors I can't imagine a little extra latency being a terrible thing.

Kind of makes me want to make a bunch of battery/solar nodes and just hide them places and see how far you can get a network to go :)

[gohan]

@crankycoder for sensor is not a huge problem, but if you have a button controlling an actuator then latency is bad. Also lost messages would require multiple send and thus reducing battery life.

[alowhum]

@CrankyCoder I heard that in the Netherlands at least there are technically no laws agains placing sensors in trees :-)