Best or correct way to graph sensor data?

Projects General Guidance
1

Hi all,

I have 2 arduino pro minis and 4 sensors (DHT22) that I want to see graphs of output over time. I need 2 graphs, each with 2 temperature and 2 humidity graphs. The data from the sensors is sent via nrf24l01+ transcievers to a central point (could be arduino or pi).
I would prefer to have this hosted on a pi or my Zyxel NSA325 NAS server.
I am not too sure about things like JSON, PHP, etc and have no experience of them (yet).
I have seen many approaches to this problem but none seem to do what I want in a way I understand and can modify for my needs.

So what's the best simple way to get this working?

Cheers

2

This project is anything but simple. I suggest you start small and test each simple module before you integrate them into the complete project.

Try logging data on an sd card. Try some server stuff with files from the sd card as test file.

3

Hi,

Thanks for the reply.

The project is actually fully up and running! -- Arduino's, sensors, RF modules, relays, LCD displays etc....All working and sending back data.

All I need to do is find a way to collect the data received and then graph it somehow (preferablly locally and not via an internet page).

Skywatch.

4

I'm sure there is a python library somewhere that will graph data for you. As for getting your data back to one location (Sounds like you have something picked out), you just need to send it all to one unit that is/connects to your server. Basically you'll just need to regularly poll each subsystem for information, receive it, save it somewhere, then use your choice of UI (I'd say a webpage) to display the graph. I'm sure if you google python statistics libraries, there is quick and easy way to generate a webpage based display of any data you'd like.

As for how to connect to your server, that is dependent on your application, but I imagine a couple of serial ports will work either using bluetooth or just a cable.

5

skywatch:
All I need to do is find a way to collect the data received and then graph it somehow (preferablly locally and not via an internet page).

It is not clear what is actually up and running but, if the data is being collected by an Arduino and that can be connected to a PC, you could run the data directly into a live Excel graph by using a PLX-DAQ, which is a freebie macro that enables Excel to be used a s terminal. It can't get much simpler than that.

6

Hi,

I wrote a simple example, perhaps helps: https://github.com/vmlenart/Guararduino

7

I wonder if my EzScrn project has any relevance - it can draw charts and it should be fairly easy to modify the Python code if it does not meet your needs out of the box.

...R