Android tablet  - plotting data bytes coming through Bluetooth - Page 1
Forum section: electronics / projects

author: atferrari
author_rank: Frequent Contributor
timestamp: June 05, 2015, 12:56:27 am
content: I expect to take sequences of say, 50 temperature measurements expressed by a byte each with values ranging from 0 to 255.The micro will transmit them through bluetooth to a tablet running Android 4.4 at a pace not decided yet. Say, for now, every 30 seconds.I spent two days already, reading intensively about Android but still have questions:a - What application (tablet side) could I use to receive and (save?) them?b - What application is actually able to take the above data and plot the values against an X axis (time).c - Initially I thought that a .bin file would be involved but it seems that in Android they are different than in Windows and maybe they are not needed at all. The .bin files seem to have a more or less specific use.d - The apps I've read about up to now, they all seem able to graph functions but no data values.Could anyone suggest how to handle this, based on previous experience. BTW, I am not Java, nor C conversant.Gracias for any help.

author: zapta
author_rank: Super Contributor
timestamp: June 05, 2015, 01:46:01 pm
content: Are you looking for an off the shelf Android app or do you plan to write your own?

author: atferrari
author_rank: Frequent Contributor
timestamp: June 05, 2015, 02:18:59 pm
content: Quote from: zapta on June 05, 2015, 01:46:01 pmIf at all possible something free and ready.Writting would mean learning a whole bundled of things and going out of focus on what I intend to do in the micro's side.

author: ivaylo
author_rank: Frequent Contributor
timestamp: June 06, 2015, 07:11:47 am
content: Quote from: atferrari on June 05, 2015, 12:56:27 amOne which you'll have to write yourself. There isn't an app which would connect to an arbitrary bluetooth correspondent, make sense of the incoming bytes and take another arbitrary action.

author: atferrari
author_rank: Frequent Contributor
timestamp: June 06, 2015, 11:26:33 am
content: Quote from: ivaylo on June 06, 2015, 07:11:47 amHad answers already saying totally the oposite but truth is that nobody can tell me a link for that so, yes, I am in my (slow) way to develope mine.

author: mark03
author_rank: Frequent Contributor
timestamp: June 08, 2015, 05:48:09 pm
content: I think a generic app could be written that would fill a gap. Data logging, graphing, save to file, etc. with the measurements coming in over a configurable BLE characteristic, or a very simple wifi (TCP stream) based protocol. I've often wondered if anyone has written such a thing. It would be quite useful in a variety of applications.

author: ivaylo
author_rank: Frequent Contributor
timestamp: June 09, 2015, 07:56:32 am
content: Quote from: mark03 on June 08, 2015, 05:48:09 pmSuch a thing doesn't exist for a PC, why would it exist for a tablet? What data do you pass? One bite, two bytes, four bytes,..., big endian, little endian, integer, float, ASCII, structured data, parity check, no parity check, compression, no compression, weird delimiters, synch, asynch, how many channels, etc, etc? You'd want it at any speed convenient too I guess...

author: miguelvp
author_rank: Super Contributor
timestamp: June 09, 2015, 03:27:29 pm
content: Didn't read the whole thread, but has anyone tried to suggest using a spreadsheet graphing/plotting app?Search for "plot graph android" or similar.

author: atferrari
author_rank: Frequent Contributor
timestamp: July 04, 2015, 07:07:02 pm
content: Finally decided to roll my own. The basics are solved and it serves my purpose.Here it ishttps://youtu.be/JCy21NPKMlY

author: ivaylo
author_rank: Frequent Contributor
timestamp: July 05, 2015, 07:12:39 am
content: Good job! Any plans to publish it?

author: atferrari
author_rank: Frequent Contributor
timestamp: July 05, 2015, 08:47:14 pm
content: Quote from: ivaylo on July 05, 2015, 07:12:39 amThanks!No plans for the moment. It just graphs the 260 values in each of three common .bin files. I should make it a little (or a LOT) more flexible to be of any use to someone else.I am now on the micro's side seeing how to hook a BT module to it. RN 42?Besides voting for Major I spent most of my day reading...and feeling our winter's cold!