Hey All,
Been a long-time member of PL, but been a away for many moons...
Long ago, I was dabbling into a project, and now I am back on it.
I want to make an old-school radar screen sort of thing. I have got a demo of sorts working as a programming bed, and I have all the nice tight timing under control.
With a 3000 RPM motor and hall-effect-sensor, I have really tight control over the laser, but I see that there is a 'pre-tail'. More specifically, it seems my 100mw Greenie ramps up to full brightness under TTL control. The OFF works just fine, nice and sharp and abrupt, as needed...
Originally I thought it was a programming or processor speed issue, but with all sorts of testing and programming tweaks, NOTHING I do clears it up...
So I ask the wiser-than-I folks, what gives me this tail?
Is it indeed a 'ramp-up" time? Seems on the order of 40-50 microseconds, but without a scope, it's not possible to determine that...
Should I be looking at analog modulation, with a short, dim pulse prior to going to full brightness?
Should I be looking at a beam shutter?
I'm open to any advice or testing recommendations.
Thanks all,