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Topic: Rapidly spinning laser to create one-lined image (Read 2687 times) previous topic - next topic

David82


Quote
why can't it be mentioned in one or 2 sentences? Like this, "That won't work because X, Y, Z"

This won't work because a laser presents a varying impedance to the thing driving it and so a simple resistor will not be able to give it the constant current it needs.


ok, then I figure you would just use a transistor in between the laser driver and the laser diode. That way the driver always has power applied to it and the diode would just be rapidly swtched on/off. Would that work?

Runaway Pancake

I have used this exact circuit



to control a low-power 3V laser module (inset).
"You gotta fight - for your right - to party!"
Don't react - Read.
"Who is like unto the beast? who is able to make war with him?"
It's "bipolar transistor" or "junction transistor" - "BJT" is stupid.
When all else fails, check your wiring!

David82

#32
May 13, 2012, 10:04 pm Last Edit: May 13, 2012, 10:08 pm by David82 Reason: 1
Cool. Did you just use that circuit simply for powering it or did you use it to rapidly flip it on/off over and over?

Runaway Pancake

It was in a blinking application of sorts, a "low" frequency with a narrow pulse "on" (low duty) - a great success.

"You gotta fight - for your right - to party!"
Don't react - Read.
"Who is like unto the beast? who is able to make war with him?"
It's "bipolar transistor" or "junction transistor" - "BJT" is stupid.
When all else fails, check your wiring!

zoomkat

Quote
I have used this exact circuit


Interesting circuit. Did the laser module require any external current limiting?
Google forum search: Use Google Search box in upper right side of this page.
Why I like my 2005 Rio Yellow Honda S2000  https://www.youtube.com/watch?v=pWjMvrkUqX0

Runaway Pancake

I got the modules from ebay, they have circuit boards already (you can sort of see it stuffed in in the picture up there).  So, all they need is a supply voltage.. and you can run around and be irritating.. or do something constructive.. as the spirit moves.
"You gotta fight - for your right - to party!"
Don't react - Read.
"Who is like unto the beast? who is able to make war with him?"
It's "bipolar transistor" or "junction transistor" - "BJT" is stupid.
When all else fails, check your wiring!

zoomkat

Quote
and you can run around and be irritating.. or do something constructive.. as the spirit moves.


Bad day at the Pancake House?
Google forum search: Use Google Search box in upper right side of this page.
Why I like my 2005 Rio Yellow Honda S2000  https://www.youtube.com/watch?v=pWjMvrkUqX0

David82


It was in a blinking application of sorts, a "low" frequency with a narrow pulse "on" (low duty) - a great success.


What was the actual reason why you couldn't you just use a digi out pin and the appropriate resistor to switch the laser on and off? What would've been the result if you tried to do it the way I just described?

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