Analog modulation with Flexmod P3

[532 with Envy]

The PSU is 12V @ 5A 'adjustable' power supply. The fan is from the a140 projector and runs around 7.5v @ 300mA or so.

So with this information on the PSU do you think that I could hook up the modulation to the main PSU without overpowering the 5V regulator and effecting the flow to the driver? If I could get rid of the 9V battery that would make things much cleaner.

Thanks much for your reply Shorty.:beer:

 

[ShortyInCanada]

So your PSU is rated for at least twice what you need for the laser diode.
You could easily tap that power for your voltage control circuit.
Just make sure you have a good enough heat sink for the 5V regulator as it will generate a bit more heat burning off the 7 extra volts.
Under the circumstances I believe putting extra filter capacitors and possibly a bleed off resistor would be more than enough to protect everything from the fan on the same power supply as well. Don't ask me for the specifics though...my background is a bit rusty from age and lack of use.
So the biggest danger from bad power would be when you turn it on. Have the fan come on automatically and then have a second switch to turn on power to the rest and you will probably have many years of trouble free operations.
I leave myself open for correction by the more knowledgable members though.

BTW, I like the look of the build. Would like to mimic the look in a much smaller package myself.
:beer:

 

[Cyparagon]

...make sure you have a good enough heat sink for the 5V regulator as it will generate a bit more heat burning off the 7 extra volts.

Nah, there's very little current through it. No heat sink is required.

Under the circumstances I believe putting extra filter capacitors and possibly a bleed off resistor would be more than enough to protect everything from the fan on the same power supply as well.

I don't think fans generate much electrical noise. Besides, the only other two things drawing power already have the appropriate filtering.

 

[532 with Envy]

I hooked up the fan to the PSU and everything seems to work without issue. The fan is a bit loud though....those little things really push some air! The fan turns on when I plug in the PSU and the laser is activated via the switch so there shouldn't be any problems on power up.

Now I only have two hook up terminals on my PSU, one used by the driver and the other by the fan. Can I 'buddy' up the two wires I have going to the 9V battery to power the modulation along with the driver or fan hook up?

 

[ShortyInCanada]

Lets see if we can make this simple for you...from my understanding of what has been posted here now ;
From your PSU you will need to use the + power output AND the - (ground/common) connection. Just those two.
Run those two connections to your variable voltage control "box". Inside the "box" tap into the power lines to power your variable voltage circuit. The output from your variable control "box" should have the 2 main power lines and a third wire to carry the positive variable voltage signal to the flex module in the laser 'head'.
Into the laser "head" assembly you have those 3 wires. In the laser "head" tap into the main power lines again for powering the fan. Positive to positive and negative/common/ground to the other. (you know, red to red and black to black.)
The other connections in the laser head are the 2 main power lines to the main power connections on the flexmod AND the third wire with the variable voltage signal to the + modulation connection. The common/ground is built in and connected through the flexmod to the main power common/ground connection so you don't need to worry about it.
It should be simple and easy. Keep it all together to make it clean looking.

Does that help ?

 

[532 with Envy]

That does help. Thank you for the explanation.:beer:

 

[ShortyInCanada]

NO trouble at all and you're welcome.
I read lots of these threads and understand how the fractured conversations and varied instructions can be confusing to sort through. Trying to put all the bits together can be difficult when you are also learning what it all means.
One of the benefits of being "old" i guess.

Don't forget to post some pics of you project as it goes too.

 

[Geoffcake]

After reading this whole thread I am still not sure what I need to use a voltage regulator.
I found these to 5V regulators:
Voltage Regulator LP2950ACZ-5.0 - Jaycar Electronics
7805 +5V 1A Voltage Regulator - Jaycar Electronics

I would purchase and use these but as far as I can tell they have fixed 5V outputs. Is this the case or can they be adjusted from 0-5V?

P.S. Sorry for bumping a slightly old thread.

 

[Cyparagon]

They can be 0-5V if you add a potentiometer as a voltage divider to the output.

 

[Geoffcake]

Well, thanks for clearing that up.

 

[Bionic-Badger]

You can also buy adjustable voltage regulators. The LM317 is of course a very common one, but there are ones with less drop-out or other features.