[disclosure]I worked with the designer on tweaking the specifications of this meter to fit the common laser uses and add RS232 datalogging. After completing this I have begun a group buy to get a quantity discount for us. I do not work for or have any connection other than stated to Andover Holography.[/disclosure]
I have some good news, this meter seems to have turned out very nicely. A big thanks to Tony from Andover Holography for working with me concerning the specifications.
The LPM-1
It's a nice looking unit with an easy to use menu and silver buttons, but who cares how it looks? How does it WORK?
First, you select the wavelength you want to measure from the menu, including 473, 532, 635, 660, and 808nm options. Once selected, the display is continuously updated at 2Hz with the measured value. The peak value is recorded and can be reset with the push of a button.
The really slick feature for us experimenters that none of the other portable meters have is the serial datalogging option. Automatic power-down can be turned off in the menu for long datalogging sessions.
Example datalogging plot made using the meter and excel:
It's a very easy feature to use and enables the tweaker/experimenter to monitor the output of their laser over time. The datarate is 57600-8-n-1. Samples transmitted every 0.5 seconds.
Now, I was skeptical about the accuracy claims at first when I read about this meter, is uses a monocrystalline solar cell as the sensor, and relies on I->V conversion for the measurement. After I got the temporary test unit I tested the linearity and accuracy by comparing its reading with that of my Scientech calorimeter laser meter. (I used a red diode from our group buy for the test) The results were impressive:
Linearity test comparing calorimeter laser meter reading with the LPM-1:
result: less than 2% error (within the accuracy of my control standard) within the specified range. So there's no problem there.
Here's a list of features:
· Autoranging measurement of light power in 4 ranges from ~100 uW to 100mW (800mW with ND8 option)
· At least 5% accuracy over native range
· Multiple sensor calibrations for different wavelengths :473,532,635,660, and 808nm selectable in a menu.
· 16 character by 2 line alphanumeric display
· 3 Pushbuttons provide control of measurements & configuration using a simple menu system.
· Automatic 5-minute power down to extend battery life (can be turned off for datalogging)
· RS232 datalogging capability
· Peak hold remembers the peak reading in a series
· 2Hz (2 samples/sec) update and logging rate, 400Hz internal sample rate
· Sensor at top of meter for easy, safe readings
· Rugged surface-mount component construction
· Operated on a 9V battery
Optional features:
· Range extending ND8 neutral density filter included and calibrated
· RS232 datalogging pre-built cable OR
· RS232 datalogging DIY kit
· Backlit display
The kit schematics for the RS232 interface will be posted free for those who can build their own.
I'd rate this product at 90%: great value for the price ($150 base group buy price), but limited to the discrete wavelengths it is calibrated for.
So, check out the group buy thread if you're interested.