I started out deciding which laser diode to use.
My two options are NUBB23 and NUBM38. Both diodes are usually either test parts or taken out of old projectors. This means there is not that much documentation on them.
NUBB23 is a lower power 25W diode, much easier to drive and requires less cooling. NUBM38 is much harder to drive, 75W, and requires tons of cooling. I decided to go with the NUBM38 because I was interested in the challenge.
Usually, we drive these diodes with linear voltage regulators rigged to operate in constant current mode. However, this massive diode array is driven at 60V! This is much too high for these linear regulators.
It is possible to run them as two seperate strings at around 30V each, but that is still at the upper limit of these regulators and would most likely generate tons of heat.
I found that Styropyro used the HV9910C IC in his build and looked at the datasheet. Using that, I calculated the components and drew up a schematic of the main laser driver.

I just finished designing the ESP32, USB, 3.3V reg, and the entire laser driver (which doesn’t look like much but since no one on the internet has used this before I had to figure it myself with a datasheet and a calculator). As I was working on designing the BMS, where there will be 4, 4s LiPos in series to get 16S and around 60V, I realized there was a problem with this approach. Well, a few. These batteries are expensive, designing a BMS would make the board massive, etc. etc. etc.

This is the part where we pivot direction

I just got the CRAZIEST deal on ebay for laser arrays. It’s a new model, and literally just solved all my problems.
I just dropped $140 on this so im PRAYING i can get reimbursed because I’m broke asl now. But basically it has 4 channels instead of 2, and it can take like 22V instead of 60V.
This means a few things, like I only need one battery. The BMS isn’t gonna be insanely massive, I can use a different constant current circuit, less heating, everything! This is amazing.

Time Spent: 5 Hours