How does one build a custom laser pointer?

[Rune]

I want to build a laser from scratch. I just want to know if the diode is being destroyed if I use that driver I linked.

 

[GSS]

As long as the driver isn't set more than 1A I think that diode will be fine, i'm going by what the mentioned typical current for this 635 is .750 to 1A.
I also missed the Survival Laser links and the round driver.
Wait till the experts chime though, and you can always email Survival Laser's and ask as they put the kits together.

 

[Rune]

Thanks a lot! I will do that

 

[Lifetime17]

Hi, I think by the way he says fitting, means will that driver be ok for that diode he selected.

Rich

 

[GSS]

Rune, do you live in the US?
Just asking because it opens up more building options..

 

[Rune]

No, I live in Denmark, but I have successfully bought stuff from survival lasers before.

 

[VioletGiraffe]

The driver is also set to the wanted current on a dummy test load

By the way, I've seen recommendations to use a bunch of diodes in series as a dummy load. Why is that, why so complicated? Wouldn't a resistor work just as well for setting the current? The regulator doesn't care what exactly it's pushing the current through (within reasonable limits).

 

[GSS]

By the way, I've seen recommendations to use a bunch of diodes in series as a dummy load. Why is that, why so complicated? Wouldn't a resistor work just as well for setting the current? The regulator doesn't care what exactly it's pushing the current through (within reasonable limits).

I don't know?? Just going by what I read. I don't solder much because I have a hand tremor that come and go's. So I don't get into buying the right equipment and tools like top notch DMM and power supply's. I leave the diode pin soldering and driver setup to Lifetime17 or the complete module from Dtr.
Are these working diodes or dead diodes in series? or would a dead diode's not work?

 

[VioletGiraffe]

Working, regular diodes (not LEDs). Maybe Schottky type, not sure.

 

[Immo1282]

Working, regular diodes (not LEDs). Maybe Schottky type, not sure.

The solution with diodes in the test load is to give the driver a realistic voltage drop across the load. The diodes let you work out if the driver is correctly regulating the current which it outputs. Most users here use selectable loads (or a string of diodes in series with a 1 ohm resistor or similar.

Here's a diagram for the load which I built for my use...

 

[VioletGiraffe]

So, it is to check the ability of the driver to regulate current across the steeply non-linear load that a diode is?

 

[paul1598419]

You can easily calculate the voltage drop over the entire dummy load as the rectifiers drop 0.7 volts each and the voltage drop across the 1 ohm resistor will be 1 mV= 1 mA. By using a different number of silicon rectifiers in your load you can simulate the drop in resistance of your laser diode as the current increases or the diode heats up. If you were to use just a resistor you could not tell what the voltage drop would be across it as it will constantly change with the current.

 

[LaserRanger]

What are the specifics for components? I want to build an smd type that has the header pins with a jumper as a selectable voltage drop thingy.. Or if it's easier to use through hole components, are the diodes just regular rectifiers? 1ohm 1% tolerance 10w resistor is needed?

 

[Immo1282]

What are the specifics for components? I want to build an smd type that has the header pins with a jumper as a selectable voltage drop thingy.. Or if it's easier to use through hole components, are the diodes just regular rectifiers? 1ohm 1% tolerance 10w resistor is needed?

The risk using SMD parts is that the parts you choose don't have a high enough power rating. By all means if you can find 2-5W rated SMD diodes and a 5W 1Ohm resistor in an SMD package go for it

 

[LaserRanger]

Hahaha Thanks I thought it was just me that couldn't find any. I want to make it look good and small so it doesn't take much space. I have heatsinks that we're salvaged from power tool batteries that I can add and also fans if it comes to using that as well to keep it stable in a small package format. I want to know what diodes, resistors, etc. are being used by other members with more experience than myself so that I do not kill my precious diodes

 

[Immo1282]

Pretty sure my testload uses 1N5404 diodes and a 1Ohm 5W wirewound resistor But it basically doesn't matter - any silicon rectifier diodes will work. Whatever you can get your hands on that'll cope with the power dissipation you want to use it for.