Modify Laser driver into ttl/pwm

Hi,

I have read some times on this forum.
Now I need help.

I have laser show from shinp, and I want modding into green, violet laser.
It wil combine into licht blue.

But it has one laser driver for green laser.
I can just add violet laser with laser mirror, but when no music comes then only green laser will off. (for safety)

I have build driver (see picture below), but has no ttl function.
How can I add this?


This circuit comes from zet.biz
It's usefull and works. (note R1 rate must be calculated by LD, R2 too)
Example Violet laser uses 5.2V , 100mA
Just calculate to get rate for R1.
Power source is 7.2V -> (7.2-5.2)/ 0.100 = 20 ohm.

R2 -> 5.2V x 0.100A = 0.52W

You can add diode for wrong connection protection.

But you did know already, I need ttl function for this.
Can anyone help me?....

There is no proper way to add modulation to this circuit

TLL can be achieved by shorting out the laser diode with a transistor, but the LM317 will not respond to that very well at higher frequencies. This chip is designed as a voltage stabilizer under relatively normal conditions, at which it performs reasonably well. Using it as a current source is a bit of hack to begin with, and adding fast modulation to the mix will make problems worse.

Then I have to use driverboard with ttl and copying and remodify to work with blue ray and red laser.

I know there is a driverboard with ttl to buy.....
Which is better reproduce or buy? but buying one from ebay works only till 5 volt dc, and input source of lasershow is 7.2 volt ac.

Maybe can I add transistor at power source (on negative).

It does only turn of when transistor get power.
This laser has only sound mode, so when it no music comes it turn off after 8 sec.

This ttl act as safety switch.

Cappie2000 said:

Then I have to use driverboard with ttl and copying and remodify to work with blue ray and red laser.

I know there is a driverboard with ttl to buy.....
Which is better reproduce or buy? but buying one from ebay works only till 5 volt dc, and input source of lasershow is 7.2 volt ac.

Click to expand...

Easily solved with a rectifier and voltage regulator.