I bought a 3W Blue diode laser engraver from Aliexpress back in 2019. This came with a Mana SE type clone controller (No PWM/TTL control) and a 2-pin laser module without any details of the spec on the actual laser diode. I want to replace the BenBox software and use LightBurn instead.
This is the controller board with the leftmost connector going to the AQHS laser driver which is in the second picture.
I have tried to measure the current drawn by the laser (Amp meter connected inbetween the laser driver and the module), but I’m not getting any readings on the 10A Volt/Amp meter module I’ve got available. This is the first thing that i don’t quite understand, unless the AQHS is pulsing the module?
I want to replace the controller with a Duo + CNCShield 3.51 and a new laser driver with PWM control. However as I’m not able to measure the current drawn by the laser module, I’m a bit worried that it might blow the module when starting up the driver. The new driver I’ve got is this:
Has anyone got any good suggestions as to how I can do this? Should I just turn the new laser driver potentiometer down to the minimum and then increase it bit by bit till I get a workable result?
It’s difficult to tell what “3W” means in the context of diode lasers, but a rule of thumb is that the diodes puts out maybe 20% of its input power on a sunny day with a tailwind.
If you’ve been successfully engraving with the thing, then that’s probably 3 W output (optical) power, because 3 W input would produce 600 mW of blue light that won’t do much damage to anything other than your eyes.
So the laser module wants maybe 15 W of input power, which is a little over an amp from the 12 V supply.
If the new driver comes with any doc, it should give a hint as to how to measure or set the laser diode current with pot.
However …
The AQHS driver has a “TTL” input in the upper left corner, which suggests it should know how to control the laser current based on a PWM input from the microcontroller. If that’s the case, you can use it with the Duo by connecting the Arduino’s PWM output to the TTL input and sidestep the whole current-setting thing with the new driver.
It looks like to me that the AQHS board is actually a laser module driver. I’d expect the driver to take PWM and control the LED current. Aren’t all lasers ultimately two wire after the driver?
I think @ednisley may have a point about the driver being PWM ready but I’ve never seen this AQHS driver before.
The AQHS is the original laser module that came with the kit. This is just powered on by supplying about 12v from the controller board at full burn, and about 3.2v for test. The TTL labled pin on this driver has not gone unnoticed, but I don’t want to modify the original controller/driver in case it all goes pear-shaped when trying. So the idea was to replace it with a reputable setup using their CNCShield and a new standard PWM laser driver.
I’ve now gone and tested the current draw in front of the driver rather than after and got measurements of about 0.98A at 12v - as @ednisley estimated. So with this I guess I have the measurement i need to get it all configured up using the new driver and shield without blowing the laser.
