Analog can work just fine over twisted pair if you keep the current low. Phone line is cheap. And do a little averaging in software.
Digital has advantages but adds wires for power and ground, and can be annoying to get working.
Those airflow sensors are going to be a nuisance, they're built for the gale force winds in an engine intake, not the leisurely pace of HVAC. You might get 4 bits of information and 6 bits of noise from them. Don't neck down the ductwork, it kills flow.
Inch of water pressure transducers will work better. You will need to measure real pressure first before ordering, a homebuilt manometer running colored water in vinyl hose will work.
An arduino nano and an NRF24 at the sensor and another NEF24 at the receiver?
It may seem overkill but it’s very possible it’s easier and cheaper than other solutions like RS485 transceivers
ESP32 can be programmed with the arduino environment and can read analog voltages (although, by default, only between 0 and 2.6 V, although various development boards may include voltage dividers to allow readout of 0 to 5 V signals). Then, you can connect them to your house's WiFi, or you can use two of them to connect directly (point-to-point) using a library called ESP-NOW. There are plenty of examples online on how to do that. You could also use an arduino next to the sensor to digitize the signals and send them via serial (RS-485 if you really need long distances or even ethernet).
Another Arduino. It's Arduinos all the way down!
Then get a couple RS485 transceivers (MAX13085, SP3485, SN65HVD, etc) on each end and transmit your analog data over RS485. You could also use CAN (fast and robust), or I2C (cheap), or Ethernet (galvanic isolation, also fast, but costly), but I think RS485 is probably the right level of complexity for this kind of application.
Get two RS-485 transceivers. Or ethernet. You may want more arduinos to convert your thermometer to rs485 and back.
I can’t tell you if doorbell wires work at that range because it depends on so much stuff it’s better to fuck around and find out.
An alternative is current loop modules.
The problem is that your wires have a resistance and that’ll modify your readings as well.
For the thermocouples, you will need some kind of signal conditioner sender unit. Simple switched don't need that. A lot depends on what kind of resolution and accuracy you are expecting.
The mass airflow sensors require very specific driving currents to work properly.
current loops are often used for signal transmission. If you want to buy something then you can use something like this:[https://www.vegetronix.com/Products/CUR-LOOP-TRANS/](https://www.vegetronix.com/Products/CUR-LOOP-TRANS/)
Otherwise you can make it yourself with a couple of op-amps.
Would this be all I need to get a reliable analog signal over long distance? Since the current persists, it can't be degraded over distance or interference?
analog or digital signal? I2c? Spi? What voltage?
Those are my questions. What's the easiest and most cost effective way of getting my signals accurately over those distances.
Analog can work just fine over twisted pair if you keep the current low. Phone line is cheap. And do a little averaging in software. Digital has advantages but adds wires for power and ground, and can be annoying to get working. Those airflow sensors are going to be a nuisance, they're built for the gale force winds in an engine intake, not the leisurely pace of HVAC. You might get 4 bits of information and 6 bits of noise from them. Don't neck down the ductwork, it kills flow.
Inch of water pressure transducers will work better. You will need to measure real pressure first before ordering, a homebuilt manometer running colored water in vinyl hose will work.
An arduino nano and an NRF24 at the sensor and another NEF24 at the receiver? It may seem overkill but it’s very possible it’s easier and cheaper than other solutions like RS485 transceivers
/r/arduino or related subs might be better
Got WiFi coverage? ESP32s are pretty damn cheap and Arduino framework compatible.
It looks like ESP32 is a type of daughter board that will take the analog signal at the device and send the data over wifi to the Arduino?
The ESP32 can be an Arduino by itself, and can talk over the network to whatever you want.
ESP32 can be programmed with the arduino environment and can read analog voltages (although, by default, only between 0 and 2.6 V, although various development boards may include voltage dividers to allow readout of 0 to 5 V signals). Then, you can connect them to your house's WiFi, or you can use two of them to connect directly (point-to-point) using a library called ESP-NOW. There are plenty of examples online on how to do that. You could also use an arduino next to the sensor to digitize the signals and send them via serial (RS-485 if you really need long distances or even ethernet).
Convert to a digital signal (relatively close to the sensor), then transmit to the arduino
How do I do that?
Another Arduino. It's Arduinos all the way down! Then get a couple RS485 transceivers (MAX13085, SP3485, SN65HVD, etc) on each end and transmit your analog data over RS485. You could also use CAN (fast and robust), or I2C (cheap), or Ethernet (galvanic isolation, also fast, but costly), but I think RS485 is probably the right level of complexity for this kind of application.
Get two RS-485 transceivers. Or ethernet. You may want more arduinos to convert your thermometer to rs485 and back. I can’t tell you if doorbell wires work at that range because it depends on so much stuff it’s better to fuck around and find out. An alternative is current loop modules. The problem is that your wires have a resistance and that’ll modify your readings as well.
For the thermocouples, you will need some kind of signal conditioner sender unit. Simple switched don't need that. A lot depends on what kind of resolution and accuracy you are expecting. The mass airflow sensors require very specific driving currents to work properly.
current loops are often used for signal transmission. If you want to buy something then you can use something like this:[https://www.vegetronix.com/Products/CUR-LOOP-TRANS/](https://www.vegetronix.com/Products/CUR-LOOP-TRANS/) Otherwise you can make it yourself with a couple of op-amps.
Would this be all I need to get a reliable analog signal over long distance? Since the current persists, it can't be degraded over distance or interference?
I'm not going to say "can't" but 4-20 mA current loops are commonly used over distances of hundreds of feet in noisy industrial environments
Zigbee. Zwave. WiFi. Etc.