Pulse Driven Laser

[Xplorer877]

I have 5mW green laser module and I want to make it pulse not CW. If I built a 555 timer circuit and pulse the power to the LD driver through a transistor will that work? Do the drivers and or diodes not like being turned on and off very rapidly?

Pulsed lasers are fun on a foggy night.

Any tips?

-Yaxley

 

[Kage]

The diodes don't mind at all, as they can handle pulsing well in excess of nanosecond speeds, but the driver is another matter altogether. The drivers in these pointers, as well as in most of the CW DIY projects tend to filter out any incoming pulses. You could do it at a slow rate, but probably not fast enough to create a dashed line or any real "laser showr" kind of effects. I think you would need a specially designed driver. :-/

 

[Xplorer877]

The diodes don't mind at all, as they can handle pulsing well in excess of nanosecond speeds, but the driver is another matter altogether.  The drivers in these pointers, as well as in most of the CW DIY projects tend to filter out any incoming pulses.  You could do it at a slow rate, but probably not fast enough to create a dashed line or any real "laser showr" kind of effects.  I think you would need a specially designed driver. :-/

Exactly what I wanted to hear. I guess I will have to design and perfect an adjustable pulse driver. It shouldn't be too hard.

About how much current do IR diodes from 5mW greenies require?

Thanx
-Yaxley

 

[StrictlyBudget]

[quote author=Kage link=1228365264/0#1 date=1228368124]The diodes don't mind at all, as they can handle pulsing well in excess of nanosecond speeds, but the driver is another matter altogether. The drivers in these pointers, as well as in most of the CW DIY projects tend to filter out any incoming pulses. You could do it at a slow rate, but probably not fast enough to create a dashed line or any real "laser showr" kind of effects. I think you would need a specially designed driver. :-/

Exactly what I wanted to hear. I guess I will have to design and perfect an adjustable pulse driver. It shouldn't be too hard.

About how much current do IR diodes from 5mW greenies require?

Thanx
-Yaxley[/quote]
well i'd say 400mA or slightly higher. a 5mW greenie probably uses a 200mW IR diode. you'll need to know what the power of the IR diode is.

 

[ElektroFreak]

[highlight]250 mA[/highlight] max for a 5mW green..

 

[MarioMaster]

you could also use a driver with modulation support like Drlava's Flexmod series - you could just send the 555 pulses to the modulation input of the driver

 

[jamilm9]

or a variable cap. Not sure if it would work

 

[Xplorer877]

you could also use a driver with modulation support like Drlava's Flexmod series - you could just send the 555 pulses to the modulation input of the driver

That's true but I wanna be able to control the speed of the pulse. I was thinking of just having a transistor bypass the + connection to the diode from the original driver board and using the 555 to generate the base pulse to the transistor.

 

[ElektroFreak]

[quote author=MarioMaster link=1228365264/0#5 date=1228493577]you could also use a driver with modulation support like Drlava's Flexmod series - you could just send the 555 pulses to the modulation input of the driver

That's true but I wanna be able to control the speed of the pulse. I was thinking of just having a transistor bypass the + connection to the diode from the original driver board and using the 555 to generate the base pulse to the transistor.[/quote]

If built right, this would work perfectly.

 

[Xplorer877]

I found a cool site that offers alot of info about the 555.
http://www.doctronics.co.uk/555.htm