Hi all. I am a new here. I was wondering if I can use Lora sensors to switch a electrical relay on or off?
Thanks in advance
The answer is probably yes, but whether this is practical with TTN or suitable for TTN would depend on the actual application.
Thanks LoRaTracker, can you send me a link with some sensors who can handel this?
Is LoRawan 2-way communications ?
Not really, your allowed 30 seconds of air time per day and allowed to send 10 messages a day to the sensor. You also need to be within range of a gateway.
Perhaps describe the actual application for us ?
30 seconds of airtime and 10 messages a day??? Why is that?
Yes we want to use our own gateways.
OK, We want to give customers access to electricity and measure the amount they use. When the customer leave the place they reveive a bill.
TTN is a free to use service where the infrastructure that makes it work is paid for and supported by someone else. There needs to be a fair use limit on free access.
If you need more air time or to send more messges then contact TTI for a paid for service.
Insert universal disclaimer here
You are proposing to build something involving mains electricity which is not something to be taken lightly. Do you have experience of measuring and controlling mains electricity?
Meter reading is a solved solution for LoRaWAN and there are likely to be ready made devices that fit your needs.
Hi Descartes, Thanks for answering.
We dont take this lightly:-) and we don’t have the experience yet but planning to get a electro technician onboard.
But, back to the question…I know the el-meters running on Lora, measuring the amount of kw. Now the question: is there a possibility to switch on/off by a relay or so?
Yes, the data sheets for the products you’ve found should let you know.
I haven’t found a specific product yet. I assume it needs a Arduino Board to the the switching??
That smoke you see rising up in front of your eyes, is that from the Arduino board or the skin between your right & left hand?
This not the forum for a discussion about switching mains electricity unless it involves the part numbers of the appropriate TRIAC’s and opto-isolators, thereby indicating some design knowledge of dealing with high voltage AC.
An Arduino would be one way of doing it, but this sounds like a commercial product your designing, so the use of Arduino would be less common.
Be aware that such a product will almost certainly require type approval and certification etc.
LoRaWAN is better suited to monitoring than to control
When your sensor infrequently sends measurement information, you have the option to say “oh, and it would be great if you could turn off the relay” but you can’t really be sure it will actually happen.
Unless you can tolerate a fair fraction of a day in achieving the relay change, and the possibility that sometimes it just plain won’t work at all, you probably need to use something else.
@arjanmolenaar I haven’t tried this myself, but Dragino appears to have a LoRaWAN I/O module that includes a relay. According to the specs, it also supports Class C which would imply that it can receive downlink messages at any time. Haven’t checked if TTN supports this though. It’s quite cheap, so may be worth the try.
product link: LT-22222-L LoRa I/O Controller
Dutch supplier: https://www.antratek.nl/lora-i-o-controller-lt-22222
Hi Jeroen, thanks for answering,
Maybe this is s a good start point. Great.
I will read through the specs this weekend.
I keep you posted
I’ve used https://www.reichelt.com/ie/en/lorawan-based-controller-mil-uc1114-p305303.html?r=1
Milesight UC1114 it has two relay outputs and 2 digital inputs. It’s class C and you can do very simple logic in the device combing downlinks and digital inputs to drive the relay outputs.
Relay output: 3 Amp DC (Max: 30 V) or 3 Amp AC (Max: 250 V)
Thank you very much for your suggestion, I will look into it very soon.
1 Like