OT? want to save web page image automatically

[Dave Stevens]

On Tue, 10 Nov 2020 08:49:56 +0000
David Fletcher <dave at thefletchers.net> wrote:

> On Mon, 2020-11-09 at 16:40 -0800, Dave Stevens wrote:
> > I have a web page that displays a chart of values that change once
> > per
> > hour. It it uses chart.js under node.js on mint.
> > 
> > See it here: http://209.145.101.163/24chart.html
> > 
> > If I right click on the image I have an option (in Firefox) to save
> > it
> > as a png. That works fine. What I'd like to do is save the image
> > once per hour without intervention. Does anyone know a scriptable
> > method?
> > 
> > TIA
> > 
> > Dave  
> 
> Hi Dave,
> 
> That looks good. Is it particulate matter you are charting?
> 
> One of my "lock-down projects" was to get my outside air temperature
> sensor working to my satisfaction, see
> 
> https://flightmaker.hopto.org/airtemperature.shtml
> 
> I did a little searching and found a nice single supply rail
> instrumentation amp that did the trick for me.
> 
> I'm simply keeping a log file of my readings in CSV format with UTC
> time like this
> 2020,11,10,07,15,11.0
> 2020,11,10,07,30,11.2
> 2020,11,10,07,45,11.1
> 2020,11,10,08,00,11.2
> 2020,11,10,08,15,11.4
> 2020,11,10,08,30,11.5
> 
> Would it not be better to just log your data like this so you can run
> whatever analysis you like with it any time in the future? Mine is
> just a hobby but I might be looking into doing some charting in the
> future. I know storage is cheap these days but CSV takes a lot less
> and is surely more flexible.
> 
> Dave
> 
> 

I do in fact keep readings taken about once per second then datamash
them to get an hourly. All raw readings are kept as csvs like:

2020-11-1011:00:01 concentration_pm2.5_atmos:	2 µg/m^3
2020-11-1011:00:02 concentration_pm2.5_atmos:	2 µg/m^3
2020-11-1011:00:04 concentration_pm2.5_atmos:	2 µg/m^3
2020-11-1011:00:06 concentration_pm2.5_atmos:	2 µg/m^3
2020-11-1011:00:07 concentration_pm2.5_atmos:	2 µg/m^3
2020-11-1011:00:09 concentration_pm2.5_atmos:	2 µg/m^3
2020-11-1011:00:11 concentration_pm2.5_atmos:	2 µg/m^3
2020-11-1011:00:13 concentration_pm2.5_atmos:	2 µg/m^3
2020-11-1011:00:14 concentration_pm2.5_atmos:   2 µg/m^3
2020-11-1011:00:16 concentration_pm2.5_atmos:	2 µg/m^3

I'd be interested in discussing the design more but perhaps off-list.

D