Newbie Gateway Hardware Confusion

[dbemowsk]

@johnrob said in Newbie Gateway Hardware Confusion:

Now looking into the wiring details i find the Mega2560 is 5V and the others require 3.3 V. Are level sensors my only option?
Or could I just use a Arduino Zero and not have to worry about level shifting?

I am not sure what you mean by "others require 3.3 V". What others are you referring to? As a note though, a 2560 is WAY overkill for the gateway. I run a serial gateway on my VeraPlus and it is running from an Arduino Pro Mini which is smaller than a zero, and even a nano.

[korttoma]

@dbemowsk said in Newbie Gateway Hardware Confusion:

I am not sure what you mean by "others require 3.3 V". What others are you referring to?

The I/O pins on the RFM69 radio is not 5V tolerable so a level shifter is needed when used with some arduinos.

If a Arduino Pro Mini 3.3V is used then no level shifter is needed but he will also need a "Genuine" USB FTDI adapter that can be set to 3.3V.

[JohnRob]

Quote from the how to fourm. "-- - at least if someone is thinking of building this gateway and wanting to use security they can hopefully read this thread before they start and will look at a higher level controller before they purchase the hardware. I am only trying to help others with what to me is still a simple and easy fix alas I must have upset the apple cart.
There is no big problem at all, just that it is really simple to know right now, with technology available today, if you need an Ethernet gateway and signing then use a Mega 2560 or better for the Ethernet Gateway controller to ensure you have the ram. @mfalkvidd - You state variations increase exponentially and most not under library control however using the MySensors Library and building the hardware shown and documented on this page using the sketch provided (completely under control of MySensors) you will need a Mega 2560 or better if you intend to enable signing (also under control of the Library). Do not get me wrong I really love the whole MySensors thing and have over 30 devices up and running and have enjoyed the whole learning thing however simple requirements (IMHO) like this should be detailed.*"
This led me to think I should start with to a more capable controller. So if I wanted to use a board that was 3.3v to be compatible with the W5100 and RFM69, I would have to use a Zero board, which runs an 3.3v.

[tbowmo]

@JohnRob

if you want to use W5100 and RFM69 then there is the option of buying the Sensebender Gateway as well, it has sockets / pads for both modules, and is (more or less) plug'n'play :)

[JohnRob]

@tbowmo Thanks for the response/info. I already have a Zero on order. If for some reason it doesn't pan out I will purchase the Sensebender Gateway.

[gohan]

If you have a raspberry pi nearby you can use that too, or even an esp8266

[JohnRob]

@gohan,

I wanted to stay with the Arduino's because I've done a few projects with the Pro Mini and feel more comfortable.
As for the Raspi I feel running a platform without an operating system seems simpler and more robust.

[gohan]

You still have the esp8266 option then

[JohnRob]

@dbemowsk

I just compiled the MySensors sketch (with RFM69 and W5100) and the usage was 46904 bytes.
My guess the Ethernet interface takes a lot more CPU horsepower than the serial you have.

[gohan]

Of course it does, since the serial interface is already built in while the ethernet needs an additional library that takes more memory

[dbemowsk]

@johnrob I don't see why it wouldn't work on a pro mini though. You shouldn't need a mega2560.

[mfalkvidd]

@dbemowsk the pro mini doesn't have enough flash space when adding signing and the ethernet shield library.

[JohnRob]

@gohan said in Newbie Gateway Hardware Confusion:

You still have the esp8266 option then

Thanks for the suggestion...I'm still learning the Arduino platform. I have two questions regarding the ESP8266,

1. Is there a particular implementation of the ESP8266 that works well as a gateway? (I see lots of ESP8266's)

2. Reading the requirements; the gateway software stores the NODE id's in EEPROM. I don't see any on the ESP8266. I know some µP can use blocks of flash like EEPROM but I don't have a feel if the reduced lifetime of the flash used this way is anything I should be worried about.

Thanks
John

[gohan]

I like the wemos d1 mini or pro as they have a compact size more breadboard friendly and there are a bunch of shields that you can use (if you look in openhardware.io there are some too)
About the flash, I don't know

[JohnRob]

@gohan
Thank you very much for your reply. A quick search led me to this site where I can learn more. link text

John

[mfalkvidd]

@johnrob I recommend wemos d1 mini for the same reasons as gohan.

For the flash/eeprom: mysensors handles this so there is no need to worry. A gateway can have only up to 253 nodes, so the node id will be written to maximum 254 times. That will not wear out the flash.

[gohan]

@johnrob if you want to get some, there is the official store on aliexpress, otherwise there are some clones from robodyn store

[JohnRob]

@mfalkvidd
Thank you for the explanation. I've learned a lot in this thread alone.

Question on the node id. If I end up with enough sensors to form a mesh and some of them are far enough away from the gateway to need to travel through a repeater. Would a change in "path" change the node ID or some other path related characteristic?

[gohan]

Node stays the same as it is saved in node's eeprom

[JohnRob]

Thanks to all for your help. I think I have enough information to start my gateway (as soon as the hardware arrives). My first step will be to add a potentiometer to the gateway as a test input before tackling a sensor node.

John