HLD685035K5J 685nm 35mW Diodes

[The Lightning Stalker]

There are some new 685nm diodes on eBay
and the price is pretty good, so I thought I'd
try one out, and the whole deal has been
fairly impressive.

New HLD685035K5J 685nm 35mw Red single transverse mode laser diode medical laser | eBay

This was the first diode I bought on eBay
from China that was actually properly
packaged. It came wrapped in a mylar ESD
bag and even in a diode tray!

There are no specs published anywhere on
these that I could find. They seem to hit
35mW at about 58mA. The beam
characteristics are the best I have ever
seen. The dot is nearly a perfect circle.
I highly recommend picking up one of these
while they are still around. At this price it's
hard to go wrong.

Pinout

Slightly defocused dot at about 20'

The camera is slightly confused by this nearly
IR W/L. To my eye it looks like a deep almost
purplish red.

Looking "down the barrel"

 

[crazyspaz]

It surprises me that more people haven't gotten these over the years. As you said, it really is hard to go wrong with that price. Heck, I dunno why I havent gotten one yet.

638 seems orangish red to me, while 650-660 almost seems dark pinkish. How do you perceive the color? Also, know of any driver that will supply that that low current? For that matter, are you planning on doing any power tests?

 

[The Lightning Stalker]

638 seems orangish red to me, while 650-660 almost seems dark pinkish. How do you perceive the color?

It's darker and even more pinkish/purplish
than 660. It's one of the most awesome
looking colors I have ever seen.

Also, know of any driver that will supply that that low current?

The Mini-CP (release forthcoming) does, but
the input must be between 5.5-6.5V, no
more, no less.

For that matter, are you planning on doing any power tests?

I don't plan on pushing it over 60mA since I
only have the one diode and even 200%
gains won't produce any impressive burning
capabilities. These are mostly for looking at,
and at that they do excel.

 

[3Pig]

Wow these diodes seem really cool, I really want to do a compact pen or c6 build with one, but cant find a driver that goes to such low currents any 17mm drivers that can do less than 50mA?

 

[Mattronium]

What is the voltage to the diode at that current?

 

[The Lightning Stalker]

The voltage drop of the diode @ 58mA is
2.34V. Do not rely on this as an indication
of current through the diode as you should
already know.

I've been testing with a 100Ω 1/2W carbon
resistor in series with the diode. The voltage
across the resistor is diode current (mA) /
10. With a variable voltage supply, it's easy
enough to work out.

 

[Mattronium]

You could just use the LM317 driver as long as you're using two Li-ion batteries. 2v-3v (dropout)+1.25v reference voltage = 4.25v(max)+2.35v (volts to diode)= 6.6 Volts minimum. Two Li-ion batteries will provide at lest 7 volts at a medium charge.

This is what I did with my 635nm 5mW pen laser build.

EDIT: I believe the LM317L is a smaller 100mA package that I used.

 

[The Lightning Stalker]

Here are some specs on the new drivers.

Mini-CP Specifications:
Polarity: Continuous Positive (for case positive, neutral, or isolated diodes)
Input Voltage: Vld + 3 ~ Vld + 4
Output Current: 40 ~ 900mA (Preset)
Topology: Linear
Dimensions: 9.5x17mm
Fits easily inside an AixiZ module
Price Point: $7.96
Main IC: These are NOT 1117, Continuous positive!

20mA/Div

 

[styropyro]

These are fun little laser diodes! They work great with the LM1117 chips and a resistor. The LM1117 is low dropout so you can run the whole circuit at 3V, plus it is dirt cheap!

Honestly I don't really see the color difference between this and 660nm, it just looks dimmer. Some cameras on the other hand see it a lot differently!

 

[The Lightning Stalker]

I can do an LM1117 kit with PCB and parts
and everything to assemble yourself if
anyone's interested.

 

[rhd]

These are fun little laser diodes! They work great with the LM1117 chips and a resistor. The LM1117 is low dropout so you can run the whole circuit at 3V, plus it is dirt cheap!

How do you figure you could run the whole circuit on 3V input?

The laser diode needs 2.34V (according to the above)

 

[styropyro]

^ By hooking the finished laser module up to 2 AA batteries.

 

[The Lightning Stalker]

It's actually closer to 5V since the series
resistor drops 1.25V and the dropout of the
LM1117 is 1.2V best-case.

 

[rhd]

It's actually closer to 5V since the series
resistor drops 1.25V and the dropout of the
LM1117 is 1.2V best-case.

This ^

I don't see how 3V could run any diode using an LM1117, even an IR. 3V - 1.25V = 1.75V, and you haven't even accounted for regulator dropout yet. Even if that dropout was low, like 0.75V, that would leave you 1V for the laser diode.

 

[ultimatekaiser]

I have several deep reds, and I love 'em all!

I actually just scored 2 nice 9mm 675nm lab quality melles griot laser diodes with their drivers. Gonna build with them soon!

I have an LM1117 on my 690nm and a CNI/LG driver on my 680nm

 

[The Lightning Stalker]

That is great. I was going to hold out for
690 or 700nm, but these were cheap and
now.