D4Thing - a universal display head for laser power meter sensors and a micro hotplate controller for soldering laser die.

By allowing the sensitivity of the sensor head to be manually entered and stored into flash the D4Thing may be used on practically any laser power sensor.
The maximum sensor input to the D4Thing is 2.5V so if your sensor is 200mV per W you can read up to 12.5W.  Beyond 2.5V the sensor output needs to be attenuated by 2 resistors and the sensitivity adjusted accordingly.

A 200mW high power 658nm laser diode reading 196mW

The same diode on a Laser Instrumentation Ltd Power Meter

A Green pointer on the D4Thing shows 8mW

And on the Laser Instrumentation Meter... 

The setup menu...

You can adjust sensor sensitivity

Most sensors will have a time constant of several seconds meaning you have to wait for 30 seconds to get a steady state reading.
D4Thing lets you compensate for this by looking at the rate of change of reading to extrapolate the final value.
This can be adjusted as required for different sensors.

You can also use the D4Thing to control a micro-hotplate for soldering laser diode die with indium and other low melting point solders.  O/P 1 and O/P 2 are open drain outputs.  To use them connect the +ve end of your PSU to +V1.  Connect the -ve (GND) end of your PSU to GND.  Connect your load between +V1 and OP1.   OP2 is used in the same way.

Select Temp Ctrl.

Construction info on the hotplate may be found here.