Graphs

Have you already written web applications to render
real time data in graphs?

The data (relay outputs) are captured by a microprocessor
and sent via RS232 to a Raspberry PI running Linux.

The data are time stamped (count of milliseconds).

The goal is to display the data in a graph with the time as
X axis and the relays states as Y axis. There are several relays
on a graph. The graph must be displayed on a host PC connected
to the raspberry.

I have searched the web for solutions. There are javascript
libraries that run on the browser and draw graphs. The problem
is that there are millions of solutions and I would like
to know if you have already made that sort of applications.

"Lanarcam" <lanarcam1@yahoo.fr> wrote in message 
news:55ef1452$0$3069$426a74cc@news.free.fr...

> Have you already written web applications to render
> real time data in graphs?

Yes, a long time ago. I used Java as the predominant run-in-the-browser 
technology of the time. It was a nightmare. Java was only partly to 
blame.

As you say below, JavaScript is likely to be a better way to go.

> The data (relay outputs) are captured by a microprocessor
> and sent via RS232 to a Raspberry PI running Linux.

FYI there is comp.sys.raspberry-pi if you later want to discuss that 
part of your project.

> The data are time stamped (count of milliseconds).
>
> The goal is to display the data in a graph with the time as
> X axis and the relays states as Y axis. There are several relays
> on a graph. The graph must be displayed on a host PC connected
> to the raspberry.
>
> I have searched the web for solutions. There are javascript
> libraries that run on the browser and draw graphs. The problem
> is that there are millions of solutions and I would like
> to know if you have already made that sort of applications.

Sorry, I don't know of any. You could try comp.lang.javascript. There is 
a question on 5 July this year about a JavaScript graphics library, 
albeit with a different focus but the responses may help you anyway.

James

Le 08/09/2015 19:38, James Harris a écrit :
> "Lanarcam" <lanarcam1@yahoo.fr> wrote in message
> news:55ef1452$0$3069$426a74cc@news.free.fr...
>
>> Have you already written web applications to render
>> real time data in graphs?
>
> Yes, a long time ago. I used Java as the predominant run-in-the-browser
> technology of the time. It was a nightmare. Java was only partly to blame.
>
> As you say below, JavaScript is likely to be a better way to go.
>
>> The data (relay outputs) are captured by a microprocessor
>> and sent via RS232 to a Raspberry PI running Linux.
>
> FYI there is comp.sys.raspberry-pi if you later want to discuss that
> part of your project.
>
>> The data are time stamped (count of milliseconds).
>>
>> The goal is to display the data in a graph with the time as
>> X axis and the relays states as Y axis. There are several relays
>> on a graph. The graph must be displayed on a host PC connected
>> to the raspberry.
>>
>> I have searched the web for solutions. There are javascript
>> libraries that run on the browser and draw graphs. The problem
>> is that there are millions of solutions and I would like
>> to know if you have already made that sort of applications.
>
> Sorry, I don't know of any. You could try comp.lang.javascript. There is
> a question on 5 July this year about a JavaScript graphics library,
> albeit with a different focus but the responses may help you anyway.
>
Thanks for that.

On Tue, 08 Sep 2015 19:01:05 +0200, Lanarcam wrote:

> Have you already written web applications to render real time data in
> graphs?
> 
> The data (relay outputs) are captured by a microprocessor and sent via
> RS232 to a Raspberry PI running Linux.
> 
> The data are time stamped (count of milliseconds).
> 
> The goal is to display the data in a graph with the time as X axis and
> the relays states as Y axis. There are several relays on a graph. The
> graph must be displayed on a host PC connected to the raspberry.
> 
> I have searched the web for solutions. There are javascript libraries
> that run on the browser and draw graphs. The problem is that there are
> millions of solutions and I would like to know if you have already made
> that sort of applications.

http://www.embeddedrelated.com/showthread/comp.arch.embedded/200540-1.php

or search on "Waveform display in browser".

I'm pretty sure that the consensus was that John wanted to generate a gif 
file (which can be pretty small if you're just displaying black lines on 
a white background) and do some HTML magic to make the thing update at a 
reasonable rate.

-- 

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

On Tue, 08 Sep 2015 14:22:05 -0400, rickman wrote:

> On 9/8/2015 1:59 PM, Tim Wescott wrote:
>> On Tue, 08 Sep 2015 19:01:05 +0200, Lanarcam wrote:
>>
>>> Have you already written web applications to render real time data in
>>> graphs?
>>>
>>> The data (relay outputs) are captured by a microprocessor and sent via
>>> RS232 to a Raspberry PI running Linux.
>>>
>>> The data are time stamped (count of milliseconds).
>>>
>>> The goal is to display the data in a graph with the time as X axis and
>>> the relays states as Y axis. There are several relays on a graph. The
>>> graph must be displayed on a host PC connected to the raspberry.
>>>
>>> I have searched the web for solutions. There are javascript libraries
>>> that run on the browser and draw graphs. The problem is that there are
>>> millions of solutions and I would like to know if you have already
>>> made that sort of applications.
>>
>> http://www.embeddedrelated.com/showthread/
comp.arch.embedded/200540-1.php
>>
>> or search on "Waveform display in browser".
>>
>> I'm pretty sure that the consensus was that John wanted to generate a
>> gif file (which can be pretty small if you're just displaying black
>> lines on a white background) and do some HTML magic to make the thing
>> update at a reasonable rate.
> 
> That was how John wanted to do it.  Many people offered him other
> alternatives which drew the graph in the browser.

All of which are apropos to the OP's question.

-- 

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Le 08/09/2015 19:59, Tim Wescott a écrit :
> On Tue, 08 Sep 2015 19:01:05 +0200, Lanarcam wrote:
>
>> Have you already written web applications to render real time data in
>> graphs?
>>
>> The data (relay outputs) are captured by a microprocessor and sent via
>> RS232 to a Raspberry PI running Linux.
>>
>> The data are time stamped (count of milliseconds).
>>
>> The goal is to display the data in a graph with the time as X axis and
>> the relays states as Y axis. There are several relays on a graph. The
>> graph must be displayed on a host PC connected to the raspberry.
>>
>> I have searched the web for solutions. There are javascript libraries
>> that run on the browser and draw graphs. The problem is that there are
>> millions of solutions and I would like to know if you have already made
>> that sort of applications.
>
> http://www.embeddedrelated.com/showthread/comp.arch.embedded/200540-1.php
>
> or search on "Waveform display in browser".
>
> I'm pretty sure that the consensus was that John wanted to generate a gif
> file (which can be pretty small if you're just displaying black lines on
> a white background) and do some HTML magic to make the thing update at a
> reasonable rate.
>
After reading the thread in sci.electronics.design, I am considering
using Flot and Javascript. That is Flot, Jquery and Ajax on the client
(PC) and python, JSON on the server (Raspberry). The server will update
files in the JSON format and the client will read those files
(or streams) using Ajax requests. The browser will call Ajax and
then Flot to render the data as graphs.

You learn things everyday...

Den tirsdag den 8. september 2015 kl. 22.59.52 UTC+2 skrev Lanarcam:
> Le 08/09/2015 19:59, Tim Wescott a �crit :
> > On Tue, 08 Sep 2015 19:01:05 +0200, Lanarcam wrote:
> >
> >> Have you already written web applications to render real time data in
> >> graphs?
> >>
> >> The data (relay outputs) are captured by a microprocessor and sent via
> >> RS232 to a Raspberry PI running Linux.
> >>
> >> The data are time stamped (count of milliseconds).
> >>
> >> The goal is to display the data in a graph with the time as X axis and
> >> the relays states as Y axis. There are several relays on a graph. The
> >> graph must be displayed on a host PC connected to the raspberry.
> >>
> >> I have searched the web for solutions. There are javascript libraries
> >> that run on the browser and draw graphs. The problem is that there are
> >> millions of solutions and I would like to know if you have already made
> >> that sort of applications.
> >
> > http://www.embeddedrelated.com/showthread/comp.arch.embedded/200540-1.php
> >
> > or search on "Waveform display in browser".
> >
> > I'm pretty sure that the consensus was that John wanted to generate a gif
> > file (which can be pretty small if you're just displaying black lines on
> > a white background) and do some HTML magic to make the thing update at a
> > reasonable rate.
> >
> After reading the thread in sci.electronics.design, I am considering
> using Flot and Javascript. That is Flot, Jquery and Ajax on the client
> (PC) and python, JSON on the server (Raspberry). The server will update
> files in the JSON format and the client will read those files
> (or streams) using Ajax requests. The browser will call Ajax and
> then Flot to render the data as graphs.
> 
> You learn things everyday...

this might be interesting: https://youtu.be/8ISbmQTbjDI

-Lasse

Lanarcam <lanarcam1@yahoo.fr> wrote:
> Have you already written web applications to render
> real time data in graphs?

Take a look at SVG
-- 
mac the na&iuml;f

Am Tue, 08 Sep 2015 19:01:05 +0200 schrieb Lanarcam:

> Have you already written web applications to render
> real time data in graphs?
> 
Well, it's not that real-time, but I use rrdtool to store 
temperature data and its associated rrdgraph to generate 
graphs that are referenced by an HTML page.

HTH.
Martin