Reef Discussion
The problem with lux (and lumens which is a related measure) is that, like PAR, it is a weighted measure. PAR gives more value to wavelengths with high photosynthetic response (i.e. red and blue) whereas lux gives weight to wavelengths that are easily picked up the human eye (i.e yellow and green). This means there is almost no correlation between the 2 values. Royal blue and deep red (and any LEDs that fall lower and higher than these colours respectively) do not get lumen values given by manufacturers but rather mW, this is because they have almost no lumen reading (often <10lm/W). What this means is that unless you know the correlative factor (which will be different for every light) then lux/lumen values are more or less useless. There are some rough guides floating around but even they tend to be very specific (i.e. brand and wattage of a given MH). What you would nee to do is calculate your own value based on your own lights BUT for a dimmable unit, you would have to calculate it for every combination and permutation of the dimming of different channels (i.e white 70% and blue 80% would have a very different constant to white 55% and blue 90%).
That is very similar to what I read awhile ago, about the time that the Seneye came out. Having a Lux, Kelvin & PAR meter built in was just fab I thought, until learning a bit more about LED light, which is why we never got one.
I am hoping the MagicJ had found something that would work, still hoping! :)
I am hoping the MagicJ had found something that would work, still hoping! :)
firechild, having spent the past hour or so reading various web pages and spec sheets I think I sort of understand what you are saying.
I actually found a 30+ thread dealing with a similar DIY light meter which I will have a read through tomorrow - they ended up producing their own PCB using at Atmel chip.
Note - the diode used in this board was designed for use in LCD, OLED's etc to adjust the level of backlight lighting based on the ambient light levels.
Lets not kid ourself - this is more of a toy than a quality scientific instrument but, for my purposes, I think that it will have some use.
If we use the results to compare relative levels rather than absolute levels then I think it could be useful i.e. compare the results from using 60 degree lens compared to 90 degree lens; or current of 600mA compared to 1000mA; or the leds situated at 10cm above the water level compared to 15 cm.
I actually found a 30+ thread dealing with a similar DIY light meter which I will have a read through tomorrow - they ended up producing their own PCB using at Atmel chip.
Note - the diode used in this board was designed for use in LCD, OLED's etc to adjust the level of backlight lighting based on the ambient light levels.
Lets not kid ourself - this is more of a toy than a quality scientific instrument but, for my purposes, I think that it will have some use.
If we use the results to compare relative levels rather than absolute levels then I think it could be useful i.e. compare the results from using 60 degree lens compared to 90 degree lens; or current of 600mA compared to 1000mA; or the leds situated at 10cm above the water level compared to 15 cm.
I like the way your thinking MagicJ,
At the moment we have no way of knowing when we finish a DIY built what our base levels are. If we change anything it's a guess. With what you are putting together at least we will have a starting point for our OWN build. We can track the + - as we change lens, amps or LED's in our builds. We may not be able to compare one system to another so when each person talks about Lux or PAR, it would be for their own system.
If your build can accomplish this, we are still up for one or two. Besides, who wouldn't want a new toy?? :)
At the moment we have no way of knowing when we finish a DIY built what our base levels are. If we change anything it's a guess. With what you are putting together at least we will have a starting point for our OWN build. We can track the + - as we change lens, amps or LED's in our builds. We may not be able to compare one system to another so when each person talks about Lux or PAR, it would be for their own system.
If your build can accomplish this, we are still up for one or two. Besides, who wouldn't want a new toy?? :)
This is not a bad use of the system. Traditionally the only use for lux meters was to compare relative intensities from the same light source, i.e. measuring drops in output from a fluorescent or MH lamp over time. People could keep records of luminous output and calculate when their lamp should be replaced. The measure is irrelevent but you could base your replacements on a given percentage of the initial reading. For LEDs, one use could be calculating a compensation curve when using a dimming controller. By this I mean that with most drivers, if you set your dimming value to 50%, the actual output will be some value more or less than 50%. You could calculate what dimming value would actually give you 50% outlut and modify the program accordingly.
So is there movement at the station on this little project MagicJ :)
A few of the bits have started to arrive, slowly - that's what I get for buying things with free postage from China :)
I now have my shiny new Arduino Mega 2560 together with the lux reader and I have been able to get it working.
I just need my touchscreen LCD and I will be able to get to work on a nice graphical interface - hopefully it will arrive tomorrow:rolleyes
I am guessing that the programming will take some time as I have not used a touchscreen before but it will be good practice for when I redo my aquarium controller.
I now have my shiny new Arduino Mega 2560 together with the lux reader and I have been able to get it working.
I just need my touchscreen LCD and I will be able to get to work on a nice graphical interface - hopefully it will arrive tomorrow:rolleyes
I am guessing that the programming will take some time as I have not used a touchscreen before but it will be good practice for when I redo my aquarium controller.
Hi mate, good to hear from you :)
My current controller is a bit boring at the moment - it just keeps working like it should :rolleyes So, I thought I should try something else and the touch screen LCD's are pretty cheap now - whilst looking for the screen I came across these lux boards.
Thus, a new project is born:p
Members online
No members online now.