Sick of worrying about overheating your $20 laser diode due to your crappy soldering skills? Want to quickly test many laser diodes safely without having to solder and desolder them?
Well the answer is to use female break away headers--specifically Swiss Machine Pin (see below photo) types. I added one to an order on a hunch that it might be nice for laser diodes. Headers are usually used for plugging ICs into makeshift sockets made of the headers. Each pin is electrically isolated from the other, held together by plastic and can be cut to size using wire cutters. The Swiss Machine Pin type of header is round instead of the square type, and generally grips the wires better. It's machine pin, meaning it's for smaller wires--perfect for laser diodes.
Yes, you still have to solder, but to the pins of the headers, not directly to the diode. Soldering directly to the diode pins is still best, but the female headers grip the wires firmly, meaning that that the diode will not slip from the header holes unless deliberate or excessive force is used. One could probably even hot-glue the pins for extra security and support.
Where do you get them? I bought a 1x30 for about $4 at Sparkfun. They're somewhat expensive, but that's 15 diodes you can rig up with it.
Re: Solderless diode wiring using break away heade
I use these on the test bench when designing/testing microcontroller
projects... they allow me to quickly change Xtal frequencies by switching
them out...
The only thing I've found... over time.. the internal Machine Pin connections
become a bit loose/sloppy...
For my Xtal use... it's OK... but I'm wondering about LDs like the 405nm...
When they are new they grab great...
Re: Solderless diode wiring using break away heade
It's a nice idea, but I imagine that desoldering the PCB off of the diode does more damage than soldering a simple wire to it. I suppose if you could solder a cap directly to the diode, then this would be a safe method for quickly testing diodes. However, that would require soldering to the diode, of course.
Re: Solderless diode wiring using break away heade
well, if you don't have a cap in your voltage regulator that does that... I think it should be alright. After all, batteries already provide a quite steady source of voltage that doesn't need smoothing.
Re: Solderless diode wiring using break away heade
Tw15t3r said:
well, if you don't have a cap in your voltage regulator that does that... I think it should be alright. After all, batteries already provide a quite steady source of voltage that doesn't need smoothing.
The cap is there for a reason, to prevent spikes at start-up. Second, when the diode gets dis connected, or just even slightly disconnected and later reconnected, the driver will put out it's maximum/or higher voltage and zapp the diode, even without capacitors.
I was kind of skeptical myself, but they're remarkably secure even for one pin. They're made for securing chips in place, so they have to maintain their connection quite securely. On a diode they'd be used in connected pairs so they won't twist either. I'm sure these are pretty much what those laser diode sockets Thorlabs sells for $7 are made from.
Though it's not hard for me to solder, I think I'll try these in my next build, and just secure them in with some hot glue, which I do anyway.
Re: Solderless diode wiring using break away heade
I have scoped the lm317t with a storage scope, it DOES NOT SURGE without a cap! I have looked at this very closely with 3 different scopes, one analogue, the other 2 were digital storage scopes, and I didn't see ANY surge with the ddl driver circuit when it has NO capacitor across the laser diode. I will not use a cap across the laser diode because the results with the scoped circuit have shown absolutely no overshoot when it is used in this mode. There is much more danger to the diode when the cap is present than when it is not used. I invite anyone who has seen different to please correct me if I have done this experiment incorrectly. Anyway, the point is that if you leave the cap out, these pins would be a great solution to un-necessarily heating the diode.
The way I tested the circuit was using a 1 ohm resistor in series with the diode and the scope probe was hooked in Parallel with the resistor. I switched the switch off and on and fiddled with the connection to the battery and never saw an overshoot on the scopes.
