Arduino-> iPhone app 5 data bits

[Jester]

I have a couple of IBC water totes collecting rain water. I'm adding 5x (XKC-Y25) water sensors to monitor the water level. It would be ideal if I could get this information to my iphone, either via WiFi. or Bluetooth might be an option, but distance is likely too far (about 75')

I will use an Arduino, I'm comfortable coding embedded C type code. I have no experience with app code.

I don't want to rely on any sort of cloud based app, as I find they work when you initially test them, but are unreliable after that and can be turned off at the whim of the service.

Is there any easy to use app builder that will allow me to make a super simple app that runs on my phone that communicates via Wi-Fi to the Arduino board without any cloud or 3rd party in-between nonsense that will simply take the 5 bits available on the Arduino and display them in the app?

If so suggestions please.

[macboy]

...
I will use an Arduino,
...

There are so many different "Arduino" devices with such different capabilities, that this statement means very little.

One of the easiest ways would be to choose an Arduino type device with Wi-Fi, and run a simple http server on it. Even a lowly ESP8266 can handle this easily. The web server will serve only one simple page which presents the water sensors. You can simply bring up the web page in a browser on any device on your network.  I would imagine this would be a simple task for AI: you can ask it to create a plan so that you can write the code, or ask it to write some or all of the code for you. The downside of not using a cloud service is not having access while away from home. Of course there are ways to enable this too, but I'd certainly start with getting local access working.

[Kilrah]

ESPHome would probably be a good candidate. If you have something you can run Home Assistant on then you also get the mobile app, logging, notifications, automations etc all "for free" and under your own control but it's not necessary.

[tooki]

I made an ESP32-based thermometer (with giant 7-segment display made of LED filaments) which also has wifi. It simply presents a local web server on the LAN. (Using mdns support, I don’t even need the IP address, I just open http://thermometer.local )

That could be an approach for you, if you don’t need to be able to read the sensor values from the internet.

It’s unclear which distance you’re referring to by the 75’. Do you mean from sensor to MCU? Or MCU to phone? Indoors or outdoors? Is there stuff in between? With a clear line of sight, 75’ is no problem at all for wifi.

[ledtester]

I haven't used it, but adafruit.io looks like a way to get something working quickly:

https://io.adafruit.com/

I know you are wary of depending on 3rd parties, but Adafruit has been around for a long time, has been very supportive of the maker community and I don't see them going away or drastically changing their business model.

The basic idea is this:

- your ESP32 uploads data to adafruit.io
- you build a web dashboard on adafruit.io to view the data
- your phone uses a browser to access the dashboard on adafruit.io

Youtube has a bunch of videos on it.

The free tier gives you:

30 data points per minute
30 days of data storage
Actions every 15 minutes
5 dashboards
2 WipperSnapper devices
5 groups
10 feeds

Some other offerings in this space that have a free tier:

- IOT Plotter https://iotplotter.com/ https://hackaday.com/2020/11/19/easy-iot-logging-options-for-the-beginner/
- Things Board https://thingsboard.io/
- Arduino Cloud https://cloud.arduino.cc/