EmonTX - Wireless Disable - Switch to WIFI + Change to US Mode

(Neo Web) #1


I just installed an EmonTX that I ordered a few weeks ago. It is in another building, and my plan was to use EmonESP (Which I have hooked up, and ordered with the unit) but, for some reason the 433mhz signal is penetrating some walls that I thought it would not.

It appears that sometimes it does lose signal, and I have seen it like this:

Does the emon TX have to continusly update my emonpi, or if it connects every once in a while, will it update the kwh and be accurate?

I am most likely going to do this: Disable RFM on EmonTX

I have the emonTX connected to wifi, but I have to figure out next how to link it all together. What do you think?

Help connecting EmonTX to EmonCMS over wifi using EmonESP + Data Questions
(Robert Wall) #2

Unless you have changed from the default sketch loaded in the factory, the emonTx does not accumulate the energy, it transmits the power at 10 s intervals and accumulation is done in emonCMS. Therefore, if data is lost, so is the energy for that period.
You probably have the default sketch because energy does not appear in that list of inputs.

You could change to one of the emonLibCM demonstration sketches - emonLibCM does accumulate energy, so the updated totals could be transmitted with each set of readings. But bear in mind that the longer message is prone to cause the transmitter and receiver to lose synch (this is a problem arising from the stability of the RFM69 module) so it might not work for you if you want all the powers, energies and temperatures. A solution in the form of a new standard sketch and a change to emonHub is in the pipeline, but not yet available.




(Neo Web) #3

So it is nice to know that this option does exist, but considering what you just told me, I would like to do the exact opposite. I would like to use the EmonESP wifi module, and disable the 433mhz radio stuff in the EmonTX.

I purchased all this stuff so I would not have to mess around, what is the simplest way to disable the EmonTX built in radio? Please keep in mind I do not have any flashing tools or anything.

(Neo Web) #4

I also just found out here that I should power this unit down, and change a jumper switch to US mode.

(Neo Web) #5

I just found out I have one of these:

(Robert Wall) #6

The only way is to edit and reload the sketch. And for that you need a programmer. We know the one from the shop works. I think that yours won’t work with the emonTx because it doesn’t appear to have the connection that resets the processor at the right instant so that it fails to enter programming mode.

(Neo Web) #7

I will have to get one then, for now I will unplug the antenna, and use one of these:

(Robert Wall) #8

There is a small but definite risk that you will destroy the RFM69CW module if you transmit without a matched load. If you must remove the antenna, you should use a dummy load which will absorb the radiated power; without it, the power that would have been transmitted is reflected back into the output stage and damage it. That will happen with or without that dust cap.

(Neo Web) #9

Well Robert, can you recommend a resistive cap to put on it?

(Robert Wall) #10

A 50 Ω, 20 mW dummy load with a male SMA connector - something like one of these:

Obviously, I don’t normally use USA suppliers, so I can’t recommend one local to you.

Or this from Mouser:

But the easy answer is to leave the antenna connected, just ignore the data that comes from the emonTx via the RFM and only use the WiFi values.

(Neo Web) #11

Okay, so lets finish this now.

I am going to pop the antenna back on, and not use the emontx node that connects via RF.

Can I connect the device to my emonpi, as another node or something, and just finish this?

I was looking at doing this I guess via MQTT, or HTTP but I do not know what is more reliable/what the difference is.

I just found my API key at /emoncms/feed/api, so now I just need someone to tell me to use MQTT or HTTP, and what to do first to name/connect the device correctly.

Do I add a node? Do I overwrite one of the nodes? What am I supposed to do here to connect this tx to my emon pi over EmonESP/Wfif…

I read:


I think I am going to use MQTT, but my node list is varied/how to I represent spaces…can I just create another node?:

I suppose that is what makes it confusing to start…I do not understand this at all heh.

I mean, I just went to setup Device Setup, and I see a node 15, 17, 30, emontx3, and a emontxshield

I guess that I understand that some of them are just preconfigured, but what for, and should I write over them with MQTT w/ this EmonESP…

(Neo Web) #12

So I was just reading this too:

So I am starting to understand some of these reserved nodes…but it still does not help me understand what configuration that I have to create to use HTTP or MQTT.

(Robert Wall) #13

I don’t understand all that either, so I’m afraid I can’t help with that. EmonCMS should see the data coming in via Ethrnet/Wi-Fi as another Node - I don’t have an ESP8266 so I can’t even tell you how to set that up.

(Neo Web) #14


Thanks for helping me so far. Eventually, once I get the WIFI piece sorted out, can I use the 50 Ω dummy loads on both the emontx and emonpi?

(Robert Wall) #15

You could do that. The emonPi only transmits if you turn it on (for use with the long-gone emonGLCD), so there’s little point in doing that. It will continue to pick up any signals on the band, but just ignore them.

(Neo Web) #16

Is their an internal antenna then? How does it pick up signal?

(Robert Wall) #17

I’m getting confused about what question you’re actually asking.

The danger, as I tried to explain above, is when the RFM tries to transmit and there’s nowhere for the power to go. If it’s only receiving - and there’s nothing you want to receive anyway - then there’s no need to remove the antenna, and no need to have it either.
The emonTx automatically transmits; the emonPi only transmits when you enable it in emonhub.conf. The external antenna for the RFM is not the WiFi antenna, that’s internal, on the Raspbery Pi itself.

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WiFi only EmonTX
(Neo Web) #18

@Robert.Wall sorry for the confusion. I understand your question.

I am just trying to get rid of the 433Mhz broadcast completely from any device, and disable reception of it also. I do not use it, and I have not had enough time to evaluate it from a vulnerability standpoint.

I do not have the UART I need right now, so I was just going to cap both devices if I could with the 50 ohm cap that you mentioned. This one right here:

Later, once I get some of this work unloaded, I was going to jump into the sketch in the EmonTX device, and see what I can do with the EmonPI.

(Robert Wall) #19

Tweaking the emonTx sketch is fine.

There’s little you can do with the emonPi sketch. It’s automatically reloaded every time you update the emonPi - unless you know the trick and update your emonPi as an emonBase, which fortuitously breaks the update in just the right place. Don’t ask me why it was done this way, all I can think of is “It seemed a good idea at the time.” That’s turned out not to be the case, IMO.

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(Glyn Hudson) #20

The emonPi update has now been broken out into several sections. The user can choose to update only Emoncms if required:

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