21-Cent Lasers

erco · 2014-08-30 15:11

At 10 for $2.11, shouldn't every project have at least one laser on it?

http://www.ebay.com/itm/M3AO-10pcs-5V-Laser-Diode-Module-Dot-Shape-Copper-Semiconductor-Laser-Head-Tube-/281238879744?pt=LH_DefaultDomain_0&hash=item417b24be00

No more cannibalizing pocket laser pointers, fellas. Man up and pony up. Buy ten and stash 'em until you need 'em. "Christmas in September", I can hear PhiPi already.

erco · 2014-08-30 15:15

While you're clicking and ordering, nab a pair of these assembled matrix keyboards for $1.07 each, free ship. You couldn't buy 16 switches that cheap.

http://www.ebay.com/itm/M3AO-4x4-Matrix-16-Keypad-Keyboard-Module-16-Button-Mcu-Arduino-/281209284858

User Name · 2014-08-30 15:48

erco wrote: »

At 10 for $2.11, shouldn't every project have at least one laser on it?

If you combine the streams of all ten, you get nuclear fusion!

Publison · 2014-08-30 15:53

User Name wrote: »

If you combine the streams of all ten, you get nuclear fusion!

NEVER cross the streams!

Publison · 2014-08-30 15:55

erco wrote: »

At 10 for $2.11, shouldn't every project have at least one laser on it?

http://www.ebay.com/itm/M3AO-10pcs-5V-Laser-Diode-Module-Dot-Shape-Copper-Semiconductor-Laser-Head-Tube-/281238879744?pt=LH_DefaultDomain_0&hash=item417b24be00

No more cannibalizing pocket laser pointers, fellas. Man up and pony up. Buy ten and stash 'em until you need 'em. "Christmas in September", I can hear PhiPi already.

Looks like they have the resistor on board from the photo. Plug and Play!

I'm In.

EDIT: How can they do these for 20 cents? AND free shipping. Would not fit my business model.

doggiedoc · 2014-08-30 16:10

erco wrote: »

You couldn't buy 16 switches that cheap.

Yes you can.... http://www.ebay.com/itm/M-100pcs-Tactile-Push-Button-Switch-Momentary-Tact-6x6x5mm-DIP-Through-Hole-4pin-/281176710717?pt=LH_DefaultDomain_0&hash=item4177701e3d

Publison · 2014-08-30 16:12

Ha!.........

Phil Pilgrim (PhiPi) · 2014-08-30 16:23

'Ordered a batch. Thanks, Erco!

erco wrote:

"Christmas in September", I can hear PhiPi already.

I can only hope. According to the website, it could be as late as October. Anyway, these will come in handy for my students' class project this year: a floating ROV that photographs the bottom in shallow water. The lasers will point straight down, the red dots in the photos being used as a yardstick.

-Phil

Martin_H · 2014-08-30 17:43

I'm going to buy some too. I still have on laser sensor left, and for that price I can add superfluous lasers to projects.

W9GFO · 2014-08-30 18:42

Wow. I just bought 50 lasers for less than $11! Sometimes erco's deals aren't so bad. :-)

erco · 2014-08-30 19:40

doggiedoc wrote: »

Yes you can.... http://www.ebay.com/itm/M-100pcs-Tactile-Push-Button-Switch-Momentary-Tact-6x6x5mm-DIP-Through-Hole-4pin-/281176710717?pt=LH_DefaultDomain_0&hash=item4177701e3d

Sold! This button-pushing control freak loves pushbuttons.

I'm stocking up just in case LA gets snowed in any time soon.

Heater. · 2014-08-31 02:37

That is about a thousand times cheaper than the 1mW HeNe laser I built from a kit in 1992 !
Not to mention 3 or 4 orders of magnitude lighter and 5 times the power.

Now all I need is some very small sharks.

Anyone know the coherence length of laser diodes? Can they actually be used for making white light holograms like the old HeNe? I guess google knows somewhere.

prof_braino · 2014-08-31 07:00

Time to upgrade the sharks

erco · 2014-08-31 07:11

Still waiting for Duane "Deal" Degn to weigh in...

Ron Czapala · 2014-08-31 08:26

Don't know what I'll do with them, but I ordered 20....

erco · 2014-08-31 10:16

Ron Czapala wrote: »

Don't know what I'll do with them, but I ordered 20....

Precisely the hoarding spirit I praise and promote!

NWCCTV · 2014-08-31 10:25

Don't know what I'll do with them, but I ordered 20....

Ditto!!!

doggiedoc · 2014-08-31 10:29

erco wrote: »

Precisely the hoarding spirit I praise and promote!

You'll probably want to praise me too then because I ordered:

100 of these:
$_12.JPG

500 of these:
$T2eC16Z,!yYFIc!sdVqFBSNtH,q2S!~~60_12.JPG

1000 of these:
$T2eC16dHJIYFHOH0EUNYBSQn5WP2hw~~60_12.JPG

Publison · 2014-08-31 10:30

With all the lasers we ordered, (I also got 20), we can aim them at the Apollo mirror on the moon, ( that doesn't exist), and see what we get back, using eroc's $7.00 sensors.

Publison · 2014-08-31 10:31

Starting your own store Paul?

doggiedoc · 2014-08-31 10:34

Publison wrote: »

Starting your own store Paul?

Ummm, uh. Why no Jim.

mindrobots · 2014-08-31 10:40

OK, I bought some to hoard too.

But with safety in mind, I also bought a pair of these. As Norm always reminds us about woodworking, the same applies to lasers!

Phil Pilgrim (PhiPi) · 2014-08-31 10:42

My $2.11 purchase led to another, far more expensive purchase. When I looked at the 21-cent variety, I realized that they do not have focussing lenses. So I also sprung for ten of these:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=291165255844&ssPageName=ADME:L:OC:US:3160

-Phil

Publison · 2014-08-31 11:08

Phil Pilgrim (PhiPi) wrote: »

My $2.11 purchase led to another, far more expensive purchase. When I looked at the 21-cent variety, I realized that they do not have focussing lenses. So I also sprung for ten of these:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=291165255844&ssPageName=ADME:L:OC:US:3160

-Phil

Dang Phil, will this madness ever stop?

Those are pretty sexy. The price and free shipping just made another login to PayPal.

erco · 2014-08-31 12:23

The cheapies do have a focusing lens, FYI. I ordered my ten a while ago. Necessary to adjust focus on some for a small dot.

erco · 2014-08-31 12:27

Rick: Goggles for less! http://www.ebay.com/itm/Hot-600nm-700nm-Safety-Glasses-Red-Laser-Protection-Goggle-With-Hard-Protect-Box-/271499689560?pt=LH_DefaultDomain_0&hash=item3f36a47e58

Phil Pilgrim (PhiPi) · 2014-08-31 12:40

erco wrote:

The cheapies do have a focusing lens,

Aw nuts! $28 I really didn't need to spend.

-Phil

erco · 2014-08-31 13:58

Always axe, Dawg!

MrBi11 · 2014-08-31 17:55

I have a bunch of them wired to a prop being driven by a DMX controller, made it for a lot less than any other 'laser stage lighting'

Lawson · 2014-08-31 23:31

Heater. wrote: »

That is about a thousand times cheaper than the 1mW HeNe laser I built from a kit in 1992 !
Not to mention 3 or 4 orders of magnitude lighter and 5 times the power.

Now all I need is some very small sharks.

Anyone know the coherence length of laser diodes? Can they actually be used for making white light holograms like the old HeNe? I guess google knows somewhere.

I'm guessing the coherence length is millimeters or less. They generally have bandwidths measured in nano-meters instead of the sub-pico-meter bandwidth of a HeNe.

All is not lost though. A few inexpensive parts (for optics anyway) and you can build an external cavity diode laser that matches the bandwidth of a HeNe with FAR more tuning range.

Marty

GordonMcComb · 2014-09-01 10:54

Heater. wrote: »

That is about a thousand times cheaper than the 1mW HeNe laser I built from a kit in 1992 !
Not to mention 3 or 4 orders of magnitude lighter and 5 times the power.

Now all I need is some very small sharks.

Anyone know the coherence length of laser diodes? Can they actually be used for making white light holograms like the old HeNe? I guess google knows somewhere.

See page 33 for a bit of nostalgic fun:

https://archive.org/details/radio_electronics_1989-03

Several sources quote millimeters to maybe 20 cm for coherence length, but as these are most assuredly factory rejects (unstable output, weak output, etc), I wouldn't expect much. Your HeNe laser, if not outgassed, would still be the choice for interferometry, holograms, and other experiments of yesteryear.

21-Cent Lasers

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