Test load is to simulate the voltage needed for a specific diode and the resistor is there so you can read the current passing through. The voltage pretty much depends on the current too. If you are using 3 diodes on the test load at lower currents (the voltage will be lower than if you are using 3 diodes at high current) so one setting can work for reds and 445nm it all depends on the current. That's why you need a selectable test load. You need to the read the voltage on the test load to be close to the diodes forward voltage at specific current.
I use two multimeters for that reason, one attached for reading the voltage and one across the resistor for the current. It's way easier that way.
happy to help w/any lumia questions-- the simplicity of the efx is one aspect thatI really like- I am working on two PJs ATM and they need to be so percise that lumia seems like childs play in comparison. More lumia is showing up at lasershows these days and many still love that olde school stuff. And when done right there is almost zero chance of anyone being in a danger zone. I will either find an old lumia thread and add to it or start a new one. Lumia deserves a place on the forums.---len
Thanks for the kind words and the +rep. Lumia is making a big come-back-- and its so simple yet beautiful. Low- tech for sure, but the endless kinds of material to shine thru is super. You can crudely knife edge many colors of lasers and get very cool EFX.
I good source for a nice 1/3 RPM 112vac(not reversable) motor is from Surplus Shed.
just search '1/3 rmp' SS charges only 5$ to ship as much as you want so I suggest you get several motors and any other SS items that you like- see the closeouts- and new deals. I have gotten 30+ motors from Fred as they get cheaper when you buy more and you can use many- I JB Weld( but other adhesives work and the iron in the JB makes it 'creep' up onto the magnet sides so..) good magnet to the motor and iron washers to my various glass pieces- make changing the glass a snap.