Heyas. New on forums and w00t for my first post.
Okay, here's the thing. I recently got a PHR-803T sled and decided to build a blu-ray pointer out of it. I carefully extracted the blu-ray diode by following some tutorials on i-hacked. The hardest part was removing the cooler box around it. Anyway, I managed to extract the diode and install it into one of those metal housing, I think they're called aixiz. The housing was originally made for a <5 mW red laser. After installation I soldered two wires to the positive and negative pins, added some insulation tape and and closed the case.
The next day I proceeded to test it. I have a small DC power supply with options for constant current and constant voltage. I powered on the power supply, set the options to constant voltage, and set the voltage to zero. Next I carefully attached the diode wires to the power supply and added an extra milliampere meter in between. Slowly increasing the voltage, the laser began to shine at about 3.8 volts. While previously doing a bit of research on these forums, and some other websites, I found out that a safe current for this blu-ray diode should be about 120mA. Although mine never went past 100mA, I did reach this current at about 5.0 volts. The laser was shining very brightly. Afterwards I reduced the voltage to reach the current at about 85 mA, which was the current I used through the rest of the tests. I noticed that the ray was a bit divergent, and couldn't be properly focused with the current lens, most likely because the lens were made for a different wavelength. But that was okay for my first time.
I mounted the diode on my window and pointed it towards nearby hills, away from people, vehicles, aircraft (duh). This is how I left it for about two and a half hours. The current was about the same all the time and only changed significantly, should the voltage be adjusted manually. The ray was very visible from the source, but having gone for a walk outside to observe the ray from a distance, it was invisible (air was very clear). The diode casing was not getting hot. After a while I decided it was time to turn off the device. So I slowly reduced the voltage back to zero, unplugged one of the wires from the power supply to break the loop, and then powered off the power supply.
So here's the funny part. Today I decided to give the laser another go. I powered on the power supply, made sure the voltage was set to zero, carefully reconnected the diode wire, and slowly increased the voltage. When I reached the 5.0V barrier (same as yesterday), the current was still about 100mA, but much to my surprise, the laser light output was almost nil! The laser was emitting some white and blue light, but the intensity was not even close to what I've seen yesterday. Actually, it was barely comparable! Almost none. Now this is the part I don't understand. How come the laser worked perfectly yesterday, but doesn't work any more today? How can this be? Can a laser diode degrade in a few hours of inactivity (sounds silly)? I'm pretty sure nobody has touched the laser meanwhile, and I've done just about everything to prevent damaging the diode (slowly changing voltage, not exceeding 100mA, setting voltage to zero before starting or shutting it down, removing the cable before powering on/off the power supply to prevent possible voltage spikes, etc), yet this seems to be exactly what happened. :wtf:
What could have gone wrong? The only thing I can think of is the time I continuously operated the diode yesterday, but it's puzzling since the diode worked fine before being powered off.
~Shat
Okay, here's the thing. I recently got a PHR-803T sled and decided to build a blu-ray pointer out of it. I carefully extracted the blu-ray diode by following some tutorials on i-hacked. The hardest part was removing the cooler box around it. Anyway, I managed to extract the diode and install it into one of those metal housing, I think they're called aixiz. The housing was originally made for a <5 mW red laser. After installation I soldered two wires to the positive and negative pins, added some insulation tape and and closed the case.
The next day I proceeded to test it. I have a small DC power supply with options for constant current and constant voltage. I powered on the power supply, set the options to constant voltage, and set the voltage to zero. Next I carefully attached the diode wires to the power supply and added an extra milliampere meter in between. Slowly increasing the voltage, the laser began to shine at about 3.8 volts. While previously doing a bit of research on these forums, and some other websites, I found out that a safe current for this blu-ray diode should be about 120mA. Although mine never went past 100mA, I did reach this current at about 5.0 volts. The laser was shining very brightly. Afterwards I reduced the voltage to reach the current at about 85 mA, which was the current I used through the rest of the tests. I noticed that the ray was a bit divergent, and couldn't be properly focused with the current lens, most likely because the lens were made for a different wavelength. But that was okay for my first time.
I mounted the diode on my window and pointed it towards nearby hills, away from people, vehicles, aircraft (duh). This is how I left it for about two and a half hours. The current was about the same all the time and only changed significantly, should the voltage be adjusted manually. The ray was very visible from the source, but having gone for a walk outside to observe the ray from a distance, it was invisible (air was very clear). The diode casing was not getting hot. After a while I decided it was time to turn off the device. So I slowly reduced the voltage back to zero, unplugged one of the wires from the power supply to break the loop, and then powered off the power supply.
So here's the funny part. Today I decided to give the laser another go. I powered on the power supply, made sure the voltage was set to zero, carefully reconnected the diode wire, and slowly increased the voltage. When I reached the 5.0V barrier (same as yesterday), the current was still about 100mA, but much to my surprise, the laser light output was almost nil! The laser was emitting some white and blue light, but the intensity was not even close to what I've seen yesterday. Actually, it was barely comparable! Almost none. Now this is the part I don't understand. How come the laser worked perfectly yesterday, but doesn't work any more today? How can this be? Can a laser diode degrade in a few hours of inactivity (sounds silly)? I'm pretty sure nobody has touched the laser meanwhile, and I've done just about everything to prevent damaging the diode (slowly changing voltage, not exceeding 100mA, setting voltage to zero before starting or shutting it down, removing the cable before powering on/off the power supply to prevent possible voltage spikes, etc), yet this seems to be exactly what happened. :wtf:
What could have gone wrong? The only thing I can think of is the time I continuously operated the diode yesterday, but it's puzzling since the diode worked fine before being powered off.
~Shat
