Lightwave Halfnote Green Laser Questions

[Laser Ben]

Thanks for the move Spec!

I am wondering if anyone can help me calculate the RC combo I need for a NE555 to generate a 500hz signal? I know how to get to the frequency, but I do not know how to go backwards and get the resistor/capacitor values for a frequency. I need 500hz with a 50% duty cycle.

[dave]

http://www.uoguelph.ca/~antoon/gadgets/555/555.html

That should do it matey

[hologeek]

Ben,

Just build an astable square wave generator using the 555 ic. You don't have to be too concerned about optimal component values. Just use a couple potentiometers for R1 and R2, and while observing the output on that nice scope of yours, adjust both resistors for the desired output. R2 was about 140K and R1 about 14K C1 is 0.01uF and pick C2 to be 100nF. I did it and it worked fine.

http://www.csgnetwork.com/ne555timer2calc.html

[Laser Ben]

I thought I wanted a monostable setup with a 2ms on time and 2ms off time to make a 500hz signal.

[heroic]

I thought I wanted a monostable setup with a 2ms on time and 2ms off time to make a 500hz signal.

monostable = one-shot.
You want an astable with a 1 msec on time and a 1 msec off time. 1 msec + 1 msec = 2 msec. 2 msec ^ -1 = 500 Hz.

[drlava]

Oh man you always seem to get the best stuff for next to nothing.. so jealous!

[Laser Ben]

Come to Cali and I will show you where!

[Showlaser.dk]

Hello Ben

I have two of the exact same lasers, that i also bought from Kevin a few years ago, so if you have any questions feel free to ask - i have played a lot with them..

I ended up building my own complete PSUs for them, since the original one is overly complex and sometimes hard to start due to all the medical interlocks and stuff..

I have a spare original PSU if you ever need it..

Replacing the pump diode is quite easy, but there is a big chance that you can damage something (the yag rod) while doing it.. and please remember that these lasers should only be opened up in a cleanroom.. one single microscopic spec of dust on one of the intracavity optics and you got yourself a very expensive door stop.

Other than that this is a very nice laser - its beam divergence is a bit high - it could probably be improved by some optics, but i have not yet found something that works well without being quite complicated and expensive.. also, i dont think you can get more than around 2.2W out of them - i would recommend setting them to 2W to not stress them too much..

There is an input on the psu called "ext. pulser" or something like that - it can be used for blanking/modulation, although this will reduce the lifetime of the diodes somewhat, it might be worth it because the diodes are so cheap and easily replacable...

My heads are now mounted in two old martin mac250s so i have full dmx control over where they project, and it works really well.. i can take some pics if anyone likes..

btw: do you know if Kevin has any more of these ? - i could use a spare.. - i will send him an email..

Regards, Simon

[Showlaser.dk]

oh.. and btw. one of them is making the tunnel in the background of my signature picture..

Regards, Simon

[FourDee]

Damn damn damn
We need surplus places in Belgium. I bet tons of stuff just goed into the scrap heap