looking for way to monitor several temperatures (8) and voltages (24vac x 4) plus maybe a relay out for power on off resetting of my hvac system at home. i have 3 systems so i would like to monitor all 3 with 3 different devices and then collect and store the data in the cloud for reporting and alarming ect. i was thinking zwave and Arduino. but im no expert. im open to anything low cost and reliable. i appreciate all related advice. thank you
Hello
Welcome to the worldbest Arduino forum ever.
You might start and make some basic studies for the usage of an ESP32 for your project.
Have a nice day and enjoy coding in C++.
But you seem willing to muck about with HVAC systems, so you are several steps ahead of many others!
Do you intend to create a Z-Wave to Matter bridge for future expansion with non-Z-Wave devices?
Well I thought Z-Wave would be easy for the devices to communicate wirelessly I already have a few Z-Wave products in my house including a thermostat and I guess Alexa uses some form of Z-Way and some form of internet bridge that I use with yolink for garage door opener status. I have made a few simple projects from using tutorials with arduino. Traffic stop light with pedestrian etc. I understand the basic coding. If there's another product out there that I should use I'm open to that.
Z-Wave is a pretty old technology and is not directly compatible with newer technologies like Matter without some kind of bridge. If you think you’ll expand your system in the future you could consider that. A more powerful Arduino with, for example, an ESP32 processor and built-in wireless would be a good choice.
I'm concerned about being to keep wifi connected, was thinking a mesh Z-Wave could help me with that? No? Aren't many HVAC
t -stats Z-Wave? Thanks for your ideas so far. I'm learning.
Also when I say Z-Wave I'm considering zigbee also, I know the new and upcoming thing will be madder or thread and I'm not sure I understand the difference between all of these lol But I do believe those products won't be readily available and they'll be higher priced in the beginning. If I can get my scenario working with monitoring my HVAC systems including the one that is out in my steel building across the yard, Then I might find some more productive uses for this set up. I do actually own an HVAC company.
Saw this ... maybe the solution?
Zigbee and Z-Wave are two incompatible protocols. What you do will depend on what protocol your existing devices use. Your thermostats probably are Z-Wave. You’ll need to build/buy a Z-Wave to Wi-Fi bridge if you want to connect to Wi-Fi. Maybe a Z-Wave shield and a Arduino with Wi-Fi.
The easy way is to use a zigbee or Z-Wave to MQTT bridge application running on a PC and use your Arduino (or a Windows/Linux program) as a MQTT client.
I've used the zigbee2mqtt bridge with devices from Aqara, Sonoff and Ikea.
I haven't used the equivalent Z-Wave bridge, but I imagine the functionality would be similar.
Well at this point I don't know what all that is lol. I'm thinking I need some sensors, that will hook up to a board adurino raspberry pi ESP 32, I'm bored will also interface with a zigbee board (more possibly some other protocol capable of mesh network) Then I put the bridge to internet for the three devices so I can get the data. Of course I know I have to write the program to assign the inputs as temperatures or whatever else I'm wanting to read and write that to the micro board. I also assume that there is some program out there that I can use to access through zigbee again or whatever other protocol, an organize this information and monitor it. Ultimately I'd like to be able to monitor it from anywhere. In my head that black diagram is fairly easy too see. What goes in each one of those blocks I'm not 100% sure. Any additional help or thought you have for those details would be very greatly appreciated. I'm assuming I'm going down the right path. And realize there are probably multiple ways to do this. I'm an engineer but I haven't built a circuit with a micro controller since college. Where I was hooking it up to timers and or chips lol.
Post a list of the exact sensors you actually have, if any, with links to their data sheets.
Then, post a list of the sensors that you intend having.
Z-wave and Zigbee are popular because they allow for small inexpensive wireless sensors which are domestically acceptable in the home. For example, some are not much bigger than the coin cell that powers them.
If there are no power, size or wiring constraints then a potentially simpler Arduino all WiFi solution is viable. The quickest way to get data on the net is to use a cloud service such as Blynk, ThingSpeak, Cayenne etc.
Thanks for being such a rockstar and helping me.
selection of electronic components is really not an area of expertise for me.
I really only have the internet too rely on for this information not experience.
I'll be measuring multiple temperatures.
In an HVAC system there are several temperatures that can be helpful.
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The liquid line temperature the temperature of the condensed refrigerant flowing after it has been through the condenser It is usually in the neighborhood of 60- 120 depending upon how cool it is outside.
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The compressor discharge line temperature. This is the temperature of the line where the hot gas flows before it goes into the condenser. 150-275
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The suction line temperature. This is the temperature of the cold gas returning from the evaporator. 20- 60 degrees.
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The air temperature before the evaporator known as the return air 60-100
They are temperature after the evaporator known as the supply air 45-150 (Also would be an accurate reading of the heating season temperature supply air) -
The outside air temperature entering the condenser. 50-120
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The condenser discharge air temperature 70-150
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The temperature of the actual room or zone temperature 40-100
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Humidity level of the zone
Most of these sensors as we have spoken of would need a long wire operate in those ranges, be reliable, and the ones that are measuring the temperature of a fluid or gas running through the pipe probably need to be stainless steel in case and be tied to those lines. I purchased a few of the DS18b20 digital temperature sensors they're pretty cheap they come in a nice little stainless steel package with a good set of wire leads.from hiletgo
For humidity dht11
The sensors that measure the temperature of the liquid and discharge gas and suction gas don't have to be super accurate. Plus or minus a few degrees is fine. Of course the zone temperature like any other thermostat should be fairly accurate plus or minus a half a degree maybe. The return air and discharge air plus or minus a degree.
There are voltage signals that come from a thermostat that actually operate the equipment.
All of them are 24 volts AC range can be 20-30vac I wish we could guarantee that that voltage never gets above a certain point because I know off the shelf solutions exist for that. But I've seen that voltage transformer wander higher than 30 before.
It appears that trying to measure 24 volts ac is a bit more challenging and requires a fair amount of isolation transformers and additional circuitry step down. This might be something we do on a second round unless we could find a simple solution cost-effective to begin with. The voltages we would like to measure are
Red- supply power to the equipment
Yellow - call for cooling
White - call for heating
Green - call for blower
We simply just want to know if the voltage is there or not in other words if the thermostat is calling for heat or cool or not. Typically if you measure 24 volts from yellow to common you are calling for cooling if there is about zero volts then there's not enough voltage to pull in the contactor to turn on the compressor and you're not getting cooling.
These temperatures and statuses can be used for diagnosis. I know a lot about HVAC. In general I can write some programming which says hey if we are calling for cooling and the return temperature is this but the supply temperature is this and the discharge temperature from the compressor Is this Then there's possibly a refrigerant leak. For instance.
And so on and so forth with several HVAC issues which could be determined from inappropriate or out of bounds temperatures.
Again thank you so much for your help!
You're welcome.
Wow, that's quite an ambitious project. I have errands to run this morning but I'll read you post thoroughly later today.
In the meantime, I'm sure there are others around with ideas.
So it sounds like you don’t have any Zigbee or Z-Wave sensors already.
I’d take a look at MQTT and see if that would work for handling your 1-wire sensors with some Arduinos with Wi-Fi and collecting all the data with something like a Raspberry Pi which could also serve as the bridge for other technologies if you add commercial sensors.
For sensing the presence of 24VAC you could consider optocouplers with a simple half wave rectifier/capacitor/current limit resistor. It might be easier to use a 24VAC 4 channel relay module to sense the presence of 24VAC and use the contacts to switch digital inputs to your microcontroller.
Again, quite a project. You should start off figuring out where you can place the processors to optimize the wiring lengths and how you can power everything. Maybe then build up the temperature monitoring system and transmit that information to your bridge.
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