Hello, I am new here. My background is in radio communications and I admit to being bloody hopeless at computer projects. What I am trying to do for our local amateur radio group is to provide some way of remotely monitoring our repeater site. We need to be able to see door alarms, actual room temperature conditions, solar panel voltage and current and battery load voltage and current. I am just wondering if someone has used NODE RED to do this previously and if so could they please assist with information on how to do this?
Hi Fletch and welcome to the forum & to Node-RED.
Sounds an ideal project for Node-RED. We certainly have forum members who have done the individual things you mention.
It would also help us if you indicated what locality you are in since this may flavour what kind of hardware we might recommend. Some indication of the security threat levels would also be helpful so that we can think about sensible levels of hardware.
Hi, welcome to the forum.
All of these are possible but...
It totally depends on the hardware you have (or intend on buying). Many/Most of whay tyou are proposing have been done many times (just search the forum).
door alarms
You can buy zigbee door contacts and presence sensors. These can be integrated using zigbee2mqtt
If it is some existing alarm system, you will need to see if it has some kind of API (serail/http/mqtt) or aux relay contacts that you could connect a "sensor" to.
actual room temperature conditions
Again, Zigbee is a possibility here.
solar panel voltage and current and battery load voltage and current
Typically they are provided as an API by your hardware or some manufacturers hosted API - to get more specific answers, you will need to tell us what you have.
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Hello Julian
I am in Western Australia in a coastal town called Geraldton.
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If you have WiFi access at the Repeater Site, then that task should be fairly easy.
I have built a number of remote sensing units, using ESP32-S2-Mini devices (flashed with Micro-Python), that report some of the conditions you mentioned to a remote MQTT broker and then onto Node-RED.
Here's a link to a tutorial I posted a year ago.
Please note:
I've recently designed a simple Reporter Node that reports T/H/P, Light Level and Vin and Vreg.
I'll write a tutorial when I have some spare time.
Here's a photo of my digital board (using an ESP32-C3-Super-Mini) that supports 2 by 8-bit ports, BH1750 (light sensor) and BME280 (T/H/P sensor).
I have found the IN219 (with I2C interface) is a great chip to sense and report current load.
Note: This particular device is intended for currents up to 3.2A max and Bus Voltage of 26V max.
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Hello Stephen
The door sensor will be a simple common reed switch, the rest of the sensors I am open to suggestions.
OK, so Steve's thoughts about Zigbee are probably relevant (rather than ZWave). And I'm imagining that the threat levels probably aren't too massive.
I would consider having a local server (maybe a Raspberry Pi) onside running Node-RED and MQTT, possibly Zigbee2MQTT as well if using Zigbee. You might also consider a timeseries DB such as InfluxDB or Postgres's equivalent, that would let you keep local stats just in case needed.
Then low-cost Zigbee door and window sensors along with a Zigbee USB hub for the Pi.
You can also get zigbee temperature/humidity monitors, or - as Dave suggests - build your own using ESP devices - though that will mean adding Wi-Fi to the mix as well.
I've not done anything myself with solar but I know that plenty of people on the forum have so worth doing a trawl through previous threads.
The main thrust of the design would be to direct all relevant information to MQTT locally. What you do next will depend on what connectivity you have to the building. If it has Internet bradband access then things are easy, if 4G, you may want to restrict the amount of data. Either way, the local broker can be configured to sync data to some central point.
You could also (especially relevant for limited bandwidth) get the local Node-RED to output alerts direct to something like Telegram where lots of people could monitor things and maybe then make a more direct connection if something was off.
Tons of other ideas are perfectly possible too. For example, you can control things either via HTTP REST API's (via Node-RED), MQTT/Node-RED or Telegram/Node-RED.
You will need to wire that up to an MCP device that either connects direct to Node-RED or via network to MQTT. Either is fine.
I assume then you currently have nothing.
In which case, my recommendation would be to go with zigbee devices for ease / off-the-shelf convenience.
They are cheap, require no coding or wiring, and (important for some) dont rely on cloud services.
e.g. Smart Home Automation Products - SONOFF Official - you can pick these up for ~ÂŁ10 each
You need some sort of server to run Node-red.
It could be a WIndows PC but preferably a Linux machine.
It does not need to be powerful, and you will probably manage it remotely so no need for monitor, keyboard & mouse.
In the past I have recommended a Raspberry Pi but you need a power supply, case, micro Sd card or SSD and cooling fan.
You can almost certainly get a higher spec mini PC, a much more professional package for the same price or less, and install Linux on it.
If however your solar power is a limiting factor, a Pi has lower consumption.
Do you have a UPS?
Not sure, but I have a feeling the Repeater Site is a remote site that is not manned all the time.
If so, all it needs to do is capture the readings and send them to some central place.
I am assuming the Repeater Site has WiFi access to the Internet.
Another option is setting-up a Free-Tier account on the Oracle Cloud and installing Node-RED and Mosquitto on it (which would mean no-hardware would be needed) and club-members could login and monitor "things" using a web browser on their PC, laptop, tablet or mobile phone.
That's what I assumed too - which implies a requirement for a resilient system: hardware watchdog, read-only filesystem maybe. A Pi can provide these, don't know about the PC option.
If zigbee sensors are used, won't they still need some device to gather the messages and forward by MQTT?
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Well that could easily be handled by a free account on HealthChecks (HC).
I use HC to monitor various remote nodes around the world.
No practical experience of this myself, although I suspect there might be a ZigBee2Mqtt bridge.
I'm sure other Forum members will jump in and offer advice.
Do you actually mean "see" as in visually see if the door is open or closed (with a camera)?
Or do you mean "detect" the state of the door (and see the status on a remote dashboard)?
One thing you might want to consider is an Infrared detector (to detect people in the room).
I have these units around the four corners of my house. They have voltage-free contacts, so very easy to interface to a microcontroller like the ESP32.
If you can share more information as to what is at the Repeater Site, its physical size and solar installation - then that will certainly help in suggesting ideas to you.
Hi Fletch,
I am in Perth Western Australia, I'm a Ham operator as well so I know what your looking to do
If you would like a hand I would be happy to assist... DM me if you like
Ive been using the DTwonder board below and they seem to work really well
I wouldnt be using WIFI esp32's for this.. especially at a comms site
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