Laser power meter

I have been working on this for a couple of days. This is what I have so far. An adjustable head with DB-9 pin cable for later upgrades/changes, and one old Netgear router box. Inside is a power supply and the digital readout. I have measured with it a 50wm and the 300mw laser as shown in pic 2. The issue with the Seebeck effect is that the thermal coefficient that resides between the thermocouple junction degrades almost as fast as the reading climbs to a peak. Any comments or old meter heads gladly accepted for the project. Total investment out of pocket is less than $25 so far for everything as pictured. So what do you think?

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Originally Posted by MechEng3

I have been working on this for a couple of days. This is what I have so far. An adjustable head with DB-9 pin cable for later upgrades/changes, and one old Netgear router box. Inside is a power supply and the digital readout. I have measured with it a 50wm and the 300mw laser as shown in pic 2. The issue with the Seebeck effect is that the thermal coefficient that resides between the thermocouple junction degrades almost as fast as the reading climbs to a peak. Any comments or old meter heads gladly accepted for the project. Total investment out of pocket is less than $25 so far for everything as pictured. So what do you think?

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looks like you may need the damping circuit from the coherent.
I finally got a 212 schematic I can scan and post, will try to post tomarrow.

Steve

Looks nice, can you elaborate on your metering electronics? Old metering heads can be found on ebay once in a wihle going for as little as $30.

I picked up a few of these little guys a while back......I decided it was time to play with one of them......

http://cgi.ebay.com/4-1-2-Blue-LED-D...sid=p1638.m118

They have a few resistors that can be changed out and add a couple of trimmer pots for fine tuning. Decimal place is also easily changed. Nice for the $. I have a 12mm TEC thermally bonded to the back of the heat sink head I made. It was then coated black with a ceramic base paint, mostly carbon black. I decided to install it into something...the router box looked good to me. All the other aluminum bits are from the "drop" box.....unusable cut off pieces left for scrap metal. Intresting learning of the many uses for the amazing TEC chip. I am surprised that it works so well. Still fine tuning it......very close to Lasercheck and Liconix.