Custom Digital Ophir LPM

[justinjja]

Cool lpm I built and programed for myself:

Lpm has 2 buttons
One button zero's the output
The other button turns the backlight on/off

The LPM automatically Zero's itself when turned on
It has a built in lithium ion battery.
It can charge the battery while datalogging

This is possible by having a voltage boosting circuit +
a voltage inverting circuit

http://img59.imageshack.us/img59/7207/qkwcseeamfgzzmvfwgrrka.mp4

 

[sinner]

You are getting better at it, I do appreciate your work ! :gj:

 

[ryansoh3]

Lpm has 2 buttons
One button zero's the output
The other button turns the lcd on/off

You might want to say the button turns the LCD Backlight on and off.

Nice work though!

Cheers! :beer:

 

[jander6442]

Looking good.

 

[justinjja]

Would you have any interest in building another interface? I already have an OPHIR 20C-A-1-Y Sensor. If so please PM me to discuss the details.

I could build a few of these, they would cost about $200 each
Other than the first one that sells, it will take a while to make them.
Because I will have to order some more PCB's off of OSHPark

Also, I haven't made a datalogging program,
Mine works with Eagle eye,
if you don't have access to eagle eye you wouldn't be able to use datalogging

You might want to say the button turns the LCD Backlight on and off.

Nice work though!

Cheers! :beer:

You are correct, fixed

Edit: A most creative design & impressive workmanship on your part to say the least!

You are getting better at it, I do appreciate your work ! :gj:

Looking good.

Thanks

 

[cheech226]

lookin' good! what's the range and res?

 

[justinjja]

The 20c-a is rated for 4W's without a heatsink.
Theoretically the resolution is 5W / [2^(10+5)] = 0.15mW

but I have it truncated to 1mW resolution

 

[random person]

Nice meter mate

I thought about using those 20c-a ophir sensors however one thing bothered me. A full part # for those sensors are something like: 20C-A-1-Y.
20C-A indicated the type of sensor,
-1 = 1mW per mV
-Y = 1064 nm = calibration wavelength.

As specified in the datasheet for these devices, they are calibrated to a particular wavelength. So how do you ensure their responsivity to a broad spectrum of wavelengths without doing additional calibration?

 

[justinjja]

Nice meter mate

I thought about using those 20c-a ophir sensors however one thing bothered me. A full part # for those sensors are something like: 20C-A-1-Y.
20C-A indicated the type of sensor,
-1 = 1mW per mV
-Y = 1064 nm = calibration wavelength.

As specified in the datasheet for these devices, they are calibrated to a particular wavelength. So how do you ensure their responsivity to a broad spectrum of wavelengths without doing additional calibration?

They are broadband coated,
The 1064 is just where they are most accurate.

 

[sinner]

Nice meter mate

I thought about using those 20c-a ophir sensors however one thing bothered me. A full part # for those sensors are something like: 20C-A-1-Y.
20C-A indicated the type of sensor,
-1 = 1mW per mV
-Y = 1064 nm = calibration wavelength.

As specified in the datasheet for these devices, they are calibrated to a particular wavelength. So how do you ensure their responsivity to a broad spectrum of wavelengths without doing additional calibration?

We ensure by putting different wavelengths to the test..
First off you shine a laser on a calibrated lpm for 445nm wavelength. Note the readings.
Then you shine the same laser on the ophir head.. Voila!

As far as i can remember Tom (Tsteele93) did some testing with reds and greens and he got the exact same readings on two different and calibrated lpms one being the Laserbee and the other was Ophir head.