Project overview.
I am helping a student build a system to be used in a marine biology experiment.
She is looking at the oxygen released by coral. This measurement combined with other factors can be used to calculate metabolic function.
We intend to use a material called “Optodes” It is a chemical film that is applied to a sub-straight, in our case Mylar. This Mylar strip is put in close proximity to the coral.
When this optode material is exposed to a specific wavelength of light it fluoresces. The amount of signal in a specific wavelength indicates oxygen levels.
We will be using a Canon G11 to record the signal. We are running a hack on the camera (CHDK) that allows us to control all functions of the camera run scripts and record in RAW.
We use (rawhide) to separate the RGB channels and write the values to an Excel file.
To excite the Optodes we use Royal Blue Tri-Star Rebel Led’s.
We have successfully been able to do this on the bench.
So far we have been working on the bench. We turn on the bank of Led’s take a picture and turn off the Led’s
In the field we will need to take a time series over 24 hours. The CHDK hack allows us to run a time laps script, so the camera will fire at a predetermined interval. For sake of discussion every hour.
The task of turning on the LED bank still remains. A Led flash would be a sophisticated solution but I am reluctant to try to build a synchronized device on relative short deadline.
Another solution is to just turn the bank of Led’s on take the picture and turn it off again.
What I would like to build is something like a slave flash trigger, but add a time delay to keep the Led’s on for a few seconds.
We need a circuit that switches on, triggered by a optical pulse (flash) or the sync out from the camera.
Runs a timer between 0 and 6 seconds and turn off again.
There are a few ways this Led switch could be used.
1, Program the camera to take 2 pictures for every data point ~ 1hour intervals. The flash is set to on.
A photo detector sees the flash and turns the Led bank on, runs a timer and turns off. The time is set to overlap the second exposure.
The first flash would be just a wakeup for the Led bank, the second image would be the data.
2, Some underwater camera cases have a connector for flash sync.
In this case connect the sync to the circuit and program camera as above, to take two pictures.
3, We might be able to program the focus assist light to go on before the picture is taken.
In this case it would turn on the led bank and only one picture would be needed.
Since battery consumption is critical option 2 or 3 would be preferable.
I need to know what the power consumption will be, I can fit seven NIMH - D cells in the case.
That would give me 12000mah @ 10.5 volt
I have the underwater housing issue under control, two Sea and Sea Model 300 casings.
LED bank.
9 X 875mw royal blue Led’s ( 3 X 20mm tri-stars )
https://www.luxeonstar.com/Royal-Blue-447-5-nm-20mm-Tri-Star-Rebel-p/mr-r0500-20t.htm.
They would be wired three in series, three in parallel.
I think I can use the power module A900-D-V-2100 BuckBlock
**broken link removed**
Thanks for any help,
If you are in the San Diego area give me a call, 619 990 1299
Mark
SDSU
I am helping a student build a system to be used in a marine biology experiment.
She is looking at the oxygen released by coral. This measurement combined with other factors can be used to calculate metabolic function.
We intend to use a material called “Optodes” It is a chemical film that is applied to a sub-straight, in our case Mylar. This Mylar strip is put in close proximity to the coral.
When this optode material is exposed to a specific wavelength of light it fluoresces. The amount of signal in a specific wavelength indicates oxygen levels.
We will be using a Canon G11 to record the signal. We are running a hack on the camera (CHDK) that allows us to control all functions of the camera run scripts and record in RAW.
We use (rawhide) to separate the RGB channels and write the values to an Excel file.
To excite the Optodes we use Royal Blue Tri-Star Rebel Led’s.
We have successfully been able to do this on the bench.
So far we have been working on the bench. We turn on the bank of Led’s take a picture and turn off the Led’s
In the field we will need to take a time series over 24 hours. The CHDK hack allows us to run a time laps script, so the camera will fire at a predetermined interval. For sake of discussion every hour.
The task of turning on the LED bank still remains. A Led flash would be a sophisticated solution but I am reluctant to try to build a synchronized device on relative short deadline.
Another solution is to just turn the bank of Led’s on take the picture and turn it off again.
What I would like to build is something like a slave flash trigger, but add a time delay to keep the Led’s on for a few seconds.
We need a circuit that switches on, triggered by a optical pulse (flash) or the sync out from the camera.
Runs a timer between 0 and 6 seconds and turn off again.
There are a few ways this Led switch could be used.
1, Program the camera to take 2 pictures for every data point ~ 1hour intervals. The flash is set to on.
A photo detector sees the flash and turns the Led bank on, runs a timer and turns off. The time is set to overlap the second exposure.
The first flash would be just a wakeup for the Led bank, the second image would be the data.
2, Some underwater camera cases have a connector for flash sync.
In this case connect the sync to the circuit and program camera as above, to take two pictures.
3, We might be able to program the focus assist light to go on before the picture is taken.
In this case it would turn on the led bank and only one picture would be needed.
Since battery consumption is critical option 2 or 3 would be preferable.
I need to know what the power consumption will be, I can fit seven NIMH - D cells in the case.
That would give me 12000mah @ 10.5 volt
I have the underwater housing issue under control, two Sea and Sea Model 300 casings.
LED bank.
9 X 875mw royal blue Led’s ( 3 X 20mm tri-stars )
https://www.luxeonstar.com/Royal-Blue-447-5-nm-20mm-Tri-Star-Rebel-p/mr-r0500-20t.htm.
They would be wired three in series, three in parallel.
I think I can use the power module A900-D-V-2100 BuckBlock
**broken link removed**
Thanks for any help,
If you are in the San Diego area give me a call, 619 990 1299
Mark
SDSU