What do i need to do runtime graphs?

[x2x3x2]

Was just wondering what kinda equipments and software would be needed to do those nice looking runtime graphcs as done by Newbie and Chevrofreak for example?

Thanks in advance.

 

[ViReN]

a $20K integrating sphere, lights, batteries and Cray Computer :nana:

ok.. just joking...

seriously, for relative runtimes you can have a simple solar cell and measure current across it... log it against time.

if you want to have "overall" light readings, put the solar cell in a box / sphere, don't let direct light fall over it

As a better alternative, You can use a cheap Chinese $30 light meter too however for better results i would recommend data logging Extech 407026 / 401036

 

[abvidledUK]

Photographic Exposure Meter

12" ruler

Kitchen timer

Lined pad

Pencil

Patience.

Excel

Imageshack.

CPF

 

[Curious_character]

a $20K integrating sphere, lights, batteries and Cray Computer :nana:

ok.. just joking...

seriously, for relative runtimes you can have a simple solar cell and measure current across it... log it against time.

if you want to have "overall" light readings, put the solar cell in a box / sphere, don't let direct light fall over it

As a better alternative, You can use a cheap Chinese $30 light meter too however for better results i would recommend data logging Extech 407026 / 401036

I looked into the solar cell idea when I first got interested in this. I found that the output was very non-linear if I just measured the short-circuit current with a DVM. What you need, it turns out, is a very good short circuit, much better than you can get with any common DVM. It's an easy job with an op amp for anyone with a basic acquaintance with analog electronics, but I elected not to spend the time trying to calibrate it and just bought one of the cheap $30 lux meters from eBay. It gives me readings that are often surprisingly similar to values in reviews. I've also found it to be very linear, so I can get very measurements of the relative brightness of different lights.

I've made tons of graphs with the light meter, but it requires taking a bunch of manual readings. What I haven't looked into is how easy or difficult it would be to extract a value from it for input to a computer, which of course would be necessary to automate the process. One of these days when I have the time. . .

c_c

 

[abvidledUK]

In the early days of my RT's, I pointed a camera at the Meter / travel clock, and recorded onto DVD.

Using 5 min skip on DVD, it was a doddle to note readings every 15 mins or so.

Just find it easier these days to do it manually, as very few torches have RT's in excess of 2 hours.

And I fit it in with other household duties.