Radiant Electronics X4 at less than 10mw, how accurate?

[Rifter]

Ive been told Laser glow's lasers are measured and accurate when they ship, and I ordered a 3-5mw green and red from them so when they show up and the X4 shows up ill test them and report back.

 

[ScottW]

Ive been told Laser glow's lasers are measured and accurate when they ship, and I ordered a 3-5mw green and red from them so when they show up and the X4 shows up ill test them and report back.

Looking forward to it. I put up a graph from the X4 in a build thread for the Aixiz 8x31 module I mentioned in an earlier post. It shows a definite "stairstep" I assume is related to resolution, but provides repeatable results that "seem to match" the advertised power of the module.

I am interested to see someone test a "verified" 5-10mW on the X4, and see what it's accuracy really is at that low power.

 

[Rifter]

So I have been playing with my x4 for a hour or so now and all I can say is that to get an accurate reading at less than 5mw is very hard.

So I ended up finally getting accurate reading on my two laserglow's with the x4 heatsink and laser as close together as I could get them, less than an inch. I had this setup in a box to eliminate air movement. I powered the x4 off of a USB battery pack so there was no wires running out of the box.

Final result is my libra tested an average of 3.6mw and
peak 4.1mw and my anser tested 4.2 avg and 4.7 peak.

 

[ScottW]

So I have been playing with my x4 for a hour or so now and all I can say is that to get an accurate reading at less than 5mw is very hard.

So I ended up finally getting accurate reading on my two laserglow's with the x4 heatsink and laser as close together as I could get them, less than an inch. I had this setup in a box to eliminate air movement. I powered the x4 off of a USB battery pack so there was no wires running out of the box.

Final result is my libra tested an average of 3.6mw and
peak 4.1mw and my anser tested 4.2 avg and 4.7 peak.

Agreed -- it is difficult. The environmental influences like air movement, sunlight, skin radiation, etc. can be minimized by shielding the sensor (as you did with a box). But the distance from the sensor also makes a big difference in the reading, so I'm not sure exactly what distance results in an "accurate" reading.

I have a source I "assume to be" close to 5mW based on its specifications. At 1.0cm from the sensor the X4 measures it at 5.5mW. At 2.5cm, the reading is 3.6mW. And at 10cm, it is 2.4mW.

So I'm not sure what the "correct" distance is to get an accurate reading. Based on my results and yours, I'd say something around 1-2cm is probably appropriate when under 10mW.