Laser Pointer Forums - Discuss Laser Pointers | High Power Lasers

I built this thermal energy meter for less than $50.00.  It has a range of 0-1999mW and sensitive enough to register a cheap 5mW red pointer.  The thermopile head is capable of much higher power. The 1999mW limit is imposed by the digital panel meter display.

It's powered by two 9 volt batteries and the amplifier is my own design (though it's pretty straight forward).  The switch is an on/off switch and the knob is an offset/zero control.  The digital panel meter could be substituted with a generic multimeter to save even more money.  The rest of the parts are readily available.  It's easy enough to build that anyone who can proficiently solder and construct a breadboard current regulator should be able to tackle this.  If there is enough interest, I'll document the build-up for other DIY'ers.