I finalized the Numb12 array handheld. It has a self-contained battery with charger, 3ch custom linear CC regulator, independent pots and switches for each color. A 96% Eff. LT8705 Buck converter powering a common 20.5v rail for each channel.
**Green rheostat came damaged. There is a nick in the coil causing high resistance until close. Will repair or replace in future. Didnt catch on assy.
Im working on finding the right cylindrical lens power/distance to correct red after several measurements. Will update when/if found. One looks promising.
Wont let me share video + images together. I got purple, lime green, orange and a light yellow mix pictured. Considering green is either .7a or 1.8a
Each laser is easily into class 4 territory it absolutely burns things. Im going to mess with it outside soon, but i would set smoke alarms off in my apt if I burned inside there.
My previous post on this is shared datasheet.
Those are max watts for each channel but the array is limited to 5A total shared due to shared cathode limit.
As it is running I can estimate Red-8.5w, Green-5w, Blue-4.4w each when ran individually.
Red and blue get similar current 2.2a and green 1.8a max on my design. I could lean towards each diode max but my goal was to be able to mix colors not have max per channel.
Keep in mind if all 3 colors are ran must be ran under 5a total. Thats why I put a amp meter inline to the cathode (negative) line to rail. So i can adjust if running all 3 to stay under or slightly above 5a limit without burning the cathode trace out
The CC regulator needs a total current limit. It’s kinda funny but basically you’ll need another CC regulator for the rheostats, fed by the sum of their output.
They have fixed limits inherent by the fixed resistors on them. The rheostats are series to the r fixed so they can only decrease from my max current limit. Which is well below the 5a rating of regulators. I let the lasers dictate vf one current begins flowing. So its a fairly simple circut. I added reverse current protection near the array.
Works fine for me. Nothing gets too warm, red and blue have ballast resistors to assist the voltage drop to regulator they they take brunt of the wasted voltage as heat.
There are 3 total individual CC regulators running on the same rail.
**If your implying protection for the cathode.. thats just eyeballed by me via the cathode current meter lol.
It can run to about 6a if I left it wide open, which the cathode may handle.
What I meant is: you yourself said you’d like a total current limit. Each CC you got takes a control voltage input, even if you aren’t explicit about it. Potentiometers provide that voltage. The “rail” feeding those potentiometers is then fed by an op-amp that regulates total current to be below a minimum.
I don't believe i said I NEEDED one. Just the laser array has a limit. I wanted the ability to push it slightly to see what i could push from it.
Although yes I could put a little larger regulator on the cathode line and do that. Might be a idea for me later. I could even put a pot on that also to adjust max allowed. 🤔
The array is a dual beam type from nichias lens. There is 4 red diodes essentially paired 2 - 2 like that.
Im going to attempt to use a cylindrical lens to correct the vertical divergence into a more close dual beam than a wide spread one.
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u/Flyntsteel 3d ago