http://www.aliexpress.com/item/STM32F10 … 04541.html
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I have absolutely no idea what I am going to do with them, so any suggestions are welcome.
Heck five lazerzzzz for ten cents!!!!… 
Even if I don’t do *anything* with them… they are lasers.. for two cents each..
Pig scope with laser anybody? Do pigs with lasers beat sharks with lasers I wonder 
They would be more fun. But vastly more dangerous.
There are claims online that these little diodes are “dangerous” and “produce well over 5 mW”, I have my doubts, but I’ll let you know. I wont be staring in to the light if I can avoid it however, so time to break out the safety specs just in case.
It should be possible to overdrive them pretty hard, so long as you keep the duty cycle pretty low. Add in a heatsink and/or active cooling and we could be in for some long distance signal bouncing fun. (I’ll try not to blind too many crows or farmers). 
The short wavelength units are dangerous, but IR probably scares me the most since it is invisible.
Ray
They are not quite in to the territory of counting your fingers after every experiment to ensure they are all still there, but certainly a serious permanent eye injury hazard and not to be treated without respect.
One of my customers a few years back did sheet metal fabrication with CO2 lasers. Those things could slice you in to neat rashers without any effort. 
They made pretty neat stuff with them though. Much more precise than plasma or gas torches.
They would be more fun. But vastly more dangerous.
I have a 50W CO2 laser, of which I’m very cautious. Googles on at all times the laser PSU is switched on, even if the laser is not being fired.
I have a 50W CO2 laser, of which I’m very cautious. Googles on at all times the laser PSU is switched on, even if the laser is not being fired.
in euro your link is 2.08€, and the one above is 2.05€
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And i’m getting close to being A4 on aliexpress 
. may have been stocking up a bit too much XD. (nearing 1800 points now)
5W is the start of cutting laser territory. Still not quite “1 Gillette” but they will do a little damage. 100W and upwards, and you can cut stuff 1KW and you can cut 12mm carbon steel. …
They are great for little projects like a tripwire. One day, I should build one of those laser microphones to hear conversations through a window pane….
Also, I want to get a pack of little mirrors from the $1 store and a fog machine and set up a spy move type laser trip beam that goes all over a room.
These diodes are particularly fragile to over-anything. They are not well heatsinked and the cleaved optical surfaces are prone to damage:
Essentially, as a result, when light propagates through the cleavage plane and transits to free space from within the semiconductor crystal, a fraction of the light energy is absorbed by the surface states where it is converted to heat by phonon-electron interactions. This heats the cleaved mirror. In addition, the mirror may heat simply because the edge of the diode laser—which is electrically pumped—is in less-than-perfect contact with the mount that provides a path for heat removal. The heating of the mirror causes the bandgap of the semiconductor to shrink in the warmer areas. The bandgap shrinkage brings more electronic band-to-band transitions into alignment with the photon energy causing yet more absorption. This is thermal runaway, a form of positive feedback, and the result can be melting of the facet, known as catastrophic optical damage, or COD.
However, the low current demands at 3.3V makes them useful for many microcontroller circuits. At 11 mA, these diodes can work off the STM32F103 directly … but you are close to the per-I/O pin limit.
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