red DIY pops balloon

[joniverson]

http://s181.photobucket.com/albums/x51/joniverson/?action=view&current=New_redpopsbal1.flv

Just finished today, this is a Sony sld1234vl diode in a Radio Shack housing powered by rechargeables and an Axiz blank with lens. The balloon was about 4 feet away. Estimated power is 75 mW.

Jon

 

[greenlight]

Nice, now to light your cigar with it.

Maybe you could use it to burn the mattress.

 

[joniverson]

Nice, now to light your cigar with it.

Maybe you could use it to burn the mattress.

Not the mattress as it could use it (it's old), but I did light a match from the same position and distance:

http://s181.photobucket.com/albums/x51/joniverson/?action=view&current=New_redlightsmatchsmall.flv

 

[cdesigns]

I have 2 diodes from a LG DVD burner and also have Axiz 60mw IR laser, can I just take out the IR diode and put the LG diode on that board?

This is what I have

 

[joniverson]

If the module is of the proper size, it could be used to house the diode if the current one was removed (Axiz sells the module blanks on Ebay however). As for using the circuit board, I wouldn't use it unless I knew the current/ voltage outputs, etc.

FWIW, the circuit I used was a 6 v battery pack, suitable dropping resistor, switch, and laser diode. There is no driver board in mine. However, I am in the process of finding out what components are needed to prevent voltage/ current spikes as my understanding that using a circuit this simple is risky.

HTH,
Jon

 

[cdesigns]

If the module is of the proper size, it could be used to house the diode if the current one was removed (Axiz sells the module blanks on Ebay however). As for using the circuit board, I wouldn't use it unless I knew the current/ voltage outputs, etc.

FWIW, the circuit I used was a 6 v battery pack, suitable dropping resistor, switch, and laser diode. There is no driver board in mine. However, I am in the process of finding out what components are needed to prevent voltage/ current spikes as my understanding that using a circuit this simple is risky.

HTH,
Jon

I have one of this voltage regulators, the output voltage is steady even if the input voltage varies.

http://rangevideo.com/index.php?main_page=product_info&cPath=7_20&products_id=29

Can I power the diode using this voltage regulator , how do I connect the 3 legs of the diode to the -/+ legs on the regulator?

 

[joniverson]

I'm only an amateur as far as lasers are concerned, but I think the consensus is that current regulation is the most important. I'm not sure if the circuit you suggest would be up to the task, so maybe others with more experience could respond. My next addition or modification will be this circuit or a variation thereof:

http://www.laserpointerforums.com/forums/YaBB.pl?num=1185701612/0

I'm going for simplicity though and trying to find out if I can just use the capacitor and silicon diode across the laser diode to protect it from surges even though I'm just using a dropping resistor.

HTH,
Jon

 

[Gazoo]

Can I power the diode using this voltage regulator , how do I connect the 3 legs of the diode to the -/+ legs on the regulator?

I asked about using it in another thread, and was advised against it. The circuit in the link joniverson pointed to will give you the safest, most cost effective way of powering the diode, and it is current regulated.

 

[Gazoo]

I'm going for simplicity though and trying to find out if I can just use the capacitor and silicon diode across the laser diode to protect it from surges even though I'm just using a dropping resistor. Jon

The diode in the circuit referenced in the link serves two purposes. First, it provides polarity protection to the circuit. This means if you hook your batteries up the wrong way, it will prevent your diode from being damaged. Secondly, it drops the voltage to the diode by another half volt or so. It does nothing to prevent voltage spikes. The capacitor prevents voltage spikes. So if you want to go for simplicity, all you need is the proper resistor in series from your batteries to the diode, and a capacitor across the diode. However it is worth a few extra $$ to get the components needed to build the circuit.

 

[cdesigns]

I'm only an amateur as far as lasers are concerned, but I think the consensus is that current regulation is the most important. I'm not sure if the circuit you suggest would be up to the task, so maybe others with more experience could respond. My next addition or modification will be this circuit or a variation thereof:

http://www.laserpointerforums.com/forums/YaBB.pl?num=1185701612/0

I'm going for simplicity though and trying to find out if I can just use the capacitor and silicon diode across the laser diode to protect it from surges even though I'm just using a dropping resistor.

HTH,
Jon

The regulator I have mantains the voltage steady , no matter is the input voltage goes up and down like crazy In the minimum and maximum range. But I don't think it will mantain a regulated current

 

[teaken]

3 pin voltage regulators can be used to maintain a constant current easily. Say your regulator is 3.3 volts (pretty common) and the forward voltage of your LD is 2.5 volts (also very common) then you will have 0.8 volts to dissipate in a resistor say you want to drive the diode at 300ma then simple ohms law R=V/I so R=0.8/0.300 R~2.7 ohms (closest standard value). Then all you need is the power rating for the resistor P=I*R so P=0.3*2.7 =810mW so a 1W resistor should be fine. All you need is ohms law, easy.
You may want to add some over current and short circuit protection to the regulator which is pretty simple just look at some datasheets. Put a capacitor on the output of the regulator (should always do this anyway) to reduce transient voltages.

 

[chimo]

Sorry teaken, there are some corrections that have to be made below. Your setup still does not regulate current. It is a voltage source and has a dropping resistor.

It can be done but not in the manner depicted below. The fixed regulators will try to maintain their design voltages between the Out and Adj pins. Put a resistor in between the Vout pin and the load and connect the Adj pin after the resistor. The current will be Vfixed/R (Vfixed = the regulator voltage e.g. 3.3, 5, 8, 9, 12).

More importantly however, semiconductor devices are not passive - there is not a linear relationship for V and I. Laser diodes (and LEDs) have a very steep VI curve in their operating range. That means a very small change in voltage will result in a large change in current. In addition, the operating parameters are also affected by temperature.

Power = I*I*R not I*R (V=I*R, P=V*I) (you have it correct in the form R=V/I)

Paul

3 pin voltage regulators can be used to maintain a constant current easily. Say your regulator is 3.3 volts (pretty common) and the forward voltage of your LD is 2.5 volts (also very common) then you will have 0.8 volts to dissipate in a resistor say you want to drive the diode at 300ma then simple ohms law R=V/I so R=0.8/0.300 R~2.7 ohms (closest standard value). Then all you need is the power rating for the resistor P=I*R so P=0.3*2.7 =810mW so a 1W resistor should be fine. All you need is ohms law, easy.
You may want to add some over current and short circuit protection to the regulator which is pretty simple just look at some datasheets. Put a capacitor on the output of the regulator (should always do this anyway) to reduce transient voltages.

 

[chimo]

I have 2 diodes from a LG DVD burner and also have Axiz 60mw IR laser, can I just take out the IR diode and put the LG diode on that board?

Assuming it fits, you would still have to verify that the LD pinouts are the same to use the same driver circuit. Here are example pinouts:


By chimo