Making an android app to read serial data from serial monitor.

Hello. I have made an arduino project that uses a keypad and OLED display to save the user's input for date, price, litres and miles for my car so I can track MPG. I have done this so it saves the data to an SD card like this (Date, Price, Litres, Miles):

020819, 12.18, 15.14, 121.4
100819, 12.18, 15.14, 121.4
160819, 12.18, 15.14, 121.4
310819, 12.18, 15.14, 121.4

This is fine for a manual extract of the SD card and then just dropping the txt file into excel on my PC, I can plot a graph for MPG over time like this fine.

But I have now implemented Bluetooth to my project just to expand my coding knowledge and to eliminate the need to extract the SD card.

My question is, could you help me try to make or find an android app to either save the incoming serial data to a txt file (basically copying the txt file on the SD card), that I can then use excel on my phone to view; or to expand my knowledge even further to try and code an app of my own that simply looks at the serial monitor to then plot a graph and copy the txt file on the SD card as well maybe.

Thanks so much for any help.

DrDaveyG:
My question is, could you help me try to make or find an android app

You need to ask that question on a Forum that deals with Android programming.

One option might be to use MIT AppInventor - but I have not personal experience of it.

Another option (of which I have a little experience - but not enough to offer advice) is QPython.

...R

The easiest way to do that is to connect a serial Bluetooth module (e.g. HC-06) to the Arduino serial port (pins 0 and 1), and install a Bluetooth terminal program on the Android.

The I/O pins on many, if not all, HC-06 modules are NOT 5V tolerant, so avoid tutorials that do not recommend using level shifters. At the very least put a 1K series resistor between Arduino TX and module RX, or use a 3.3V Arduino.

This tutorial looks good: Arduino and HC-06 (ZS-040) | Martyn Currey