At most the meter jumps a value of a milliwatt, two at higher powers - the noise is virtually invisible on my oscilloscpe.
You prepared to bet your variance on that?
I guess I would if I had one, however now that I have studied the meter running for a few minutes with my Spectra Physics 127 HeNe, it does seem to "bounce" a bit more than I would like. It wasn't bouncing to any unusual numbers though, just 17-18mW.
Drlava had already suggested some sample averaging and I plan on incorporating that into the firmware immediately.
What's the error at full scale?
Try this: make a call on your cellphone. Put it on the bench a foot or so away from the meter with the call in progress. What happens next?
Have you done *any* accuracy or resolution characterization? And yet you're selling it with accuracy figures that just can't be even close to correct.
What's the tolerance stackup on your input circuitry?
What's the drift with temperature?
You're building a measurement device here. The design needs to be better than this.
How about calibration? Any support for that other than zero adjustment?
Last edited by heroic; 05-12-2010 at 13:20.
We have tested it. It's accurate to within 5%. If I had the money to throw away on building a $1500 meter, I wouldn't be selling it for $400. The meter works that's all I can see. when I put a 100mw laser onto the sensor, the meter shows 100mw +/- 5% does the same thing with a 2 Watt laser. I'm not an electrical engineer. I'm a freaking hobby laserist trying to offer up a meter to hobby laserists that would like to know if the 100mw laser they bought is really putting out close to that.. Am I happy with the results thus far? Hell yes! Have we had problems? Hell yes! Have we addressed those problems? Hell yes!
I will always work to better my products within my limited resources.