Triple Play: Matching Portable Lasers

About

I have just about enough portable lasers now: a bunch of green pens, a tiny blu-ray burner with a heatsink I machined myself, and my 300mW SKYlasers portable. So, I decided to round off my collection with a set of 3 lasers (650nm red, 532nm green, and 405nm blu-ray) in identical hosts by a LPF member named Ehgemus. This is a short build log, with beamshots at the end.

Setup

I only used the standard tools: soldering iron, mutimeter, tweezers, pliers, etc. I did need to use a drillpress to remove the back of the AixiZ modules though (more on that later).

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The Hosts

These hosts are completely custom-machined by (quite obviously) a skilled machinist. I was absolutely astounded at the build quality. The nice thing about this hosts is that they are deisgned to easily fit green modules from O-Like. However, they will also easily fit AixiZ modules, the housings most commonly used in building DIY laser setups.

The hosts are made entirely of aluminum, with the exception of silver plastic clicky switches on the back. I was particularly impressed by the quality of the threading for the back tailcap.

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Green

I used this green module from O-Like (a reliable but inexpensive provider of laser stuff). The host with only a tiny hole at the front is designed to fit this module perfectly with a CR123A battery. I have yet to meter output, but I'm fairly positive that it is well over the spec'ed 50-60mW; O-Like takes good care of their customers.

I had to make one small modification before installing the module. Using some 30-gauge wrapping wire, I made a small bypass for the momentary switch (another way to solve the problem is to just replace the switch with a wire, but I wanted something less destructive).

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Blu-Ray

As tempting as it was to buy a new 6x (or even 8x) diode and get like 300mW of violet, I decided to go the cheap route — I bought a PHR sled and used this driver from O-like. The driver is perfect for PHRs; just solder LD+ to the single pad on the underside, and LD- and the photodiode pins to the pads on the top (the photodiode pin will act as your Vcc pin since it's connected to the diode case). First, I wired up a bunch of diodes (with a ~5V voltage drop total) to set the current to around 120mA.

Unfortunately, the driver is just a little bit too long and too wide to fit in the rear cap of the AixiZ module. Normally, I wouldn't care, but the set screw on the host is so far back that you need to use the AixiZ cap. So, the solution was to drill out the back of the cap (so that it becomes a hollow cylinder) and scrape away some material from the sides of the driver. After a little work, it fit perfectly. (Of course, I forgot to take pictures of this process because I'm an idiot.

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Oh yeah, I also soldered one SMD resistor on top of an existing one (see lower right) to increase the minimum current. Actually, I just wanted to see if I could.

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Finally, in order to fit an 18650 battery in there, I needed to cut down the springs on both sides (the tailcap and the driver). After applying a little thermal compound, I installed the module.

Red

The red diode (LPC-815) is all ready to go, but unfortunately, I don't have a working driver. I thought that these would work, but on second look (i.e. after I had already bought them), they use TTL modulation. Normally, this wouldn't be an issue (I would just use it without the modulation), but I'm pretty sure the opamp on there requires 5V input, so an 18650 won't work in this case. I'll have to buy another driver before I can get this laser working.

Okay, after several weeks of procrastination and waiting, I've finally built the last laser in this set. After discovering that the driver that I originally purchased wouldn't be useful, I ordered a FlexDrive and set the current for 420mA.

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Unfortunately, after installing the drive, that's as far as I got. The diode refused to power up. So, I had to order another (and wait until I went home, where I had left all my diode extraction and press tools). But, things worked out nicely in the end.

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Instead of soldering little wires between the diode and the driver, I decided to try soldering the pins directly. Because the diode and driver is encased firmly, I don't need to worry about the solder joints breaking. Can you spot the ridiculously stupid error in this pic?

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Yeah, that's right; I had the pins swapped, so I had to resolder it. Luckily, the diode wasn't damaged.

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Beamshots

And now for the part you should have just scrolled down to see in the first place... :)

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The other blu-ray is my mini-burner using an MX Power LED flashlight.

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Guest appearance: my SKYlasers portable (left)

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Bouncing off some glass.

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