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Using a Laser for tripwire 24/7?

PickOfDestiny89

PickOfDestiny89

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Hi,
I am planning on using lasers as tripwires in a circuit to activate lights.
Now I was going to use some cheap laserpointer and take the laser out in order to shine it on an LED.
I was just thinking though, how long can I expect the Laser to last, since it is going to be running 24/7!
Should I maybe get a better quality one and build the driver myself?
I don't want to spend too much money though, because my design requires 4 of them!

Thanks in advance!
 





A laserpointer will burn out in no time. You will need an AC powered "lab" style laser for continuous duty cycle. Something low power in a good heatsink should run forever.
 
Hmm thats what I thought.
Do you have any recommendations? I mean it can be pretty low powered since it only needs to shine like 1.5m away.
 
For only 1.5m away you can use a red diode from a DVD burner set to a low current above the lasing threshold with a simple LM317 constant current driver and an Aixiz housing + heatsink. It should last for thousands of hours as long as you enclose it well to protect it from moisture and dust/debris.

Basically you just need a low power DIY 658nm build and an adequate power supply and housing. May I suggest either a photo transistor or photodiode instead of a LED though.
 
Not all laser diodes need a heat sink. If you run a true diode laser (not DPSS, as these DO have an expiration time), then you don't need a heat sink for low power (5mw or less). And certainly if you are going with Class II (< 1mw) then you for SURE don't need a heat sink.
 
Here is the laser module: 650nm 1mW 8x13mm Laser Module with Focusable Lens, AixiZ
And this is the power adapter: AixiZ Power Adapter 3.2VDC Output;, AixiZ
Click to expand...
Thats exactly what I was looking at earlier on. Looks good and should do the job!

Not all laser diodes need a heat sink. If you run a true diode laser (not DPSS, as these DO have an expiration time), then you don't need a heat sink for low power (5mw or less). And certainly if you are going with Class II (< 1mw) then you for SURE don't need a heat sink.
Click to expand...

What about the one above? How do I know if this one is a diode laser or DPSS? It doesn't say anything.

For a distance of only 1.5 meters you could easily use a
modulated (or not) IR LED and detector...

Look for LED Beam Break Detector circuits on Google..
Here's on random one...

Long Range (10mt) IR Beam Break Detector


Jerry
Click to expand...

I was thinking about that at first, but I want to measure the direction a person is going. So I want to place two lasers really close together and depending on which one is broken first I know in which direction the person is going.
From what I understand, IR LEDs don't really have a focused output or do they?

Thanks for all the replies so far! This is a great help!
 
PickOfDestiny89 said:
I was thinking about that at first, but I want to measure the direction a person is going. So I want to place two lasers really close together and depending on which one is broken first I know in which direction the person is going.
From what I understand, IR LEDs don't really have a focused output or do they?

Thanks for all the replies so far! This is a great help!
Click to expand...

It's not the IR LED Transmitter that needs to be focused to get
a signal... only one IR sensor will be triggered at a time when
breaking the beam even if the IR source is the same source...

You only need 1 IR transmitter and 2 IR receivers. Just place
the transmitting IR LED a bit past the door opening or use 2
transmitters
For even better isolation one could be modulated at 36Khz and
the other at 40Khz.


Jerry

You can contact us at any time on our Website: J.BAUER Electronics
 
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Oh man I didn't even think about that :yabbem: Yeah I guss I could just use 1 transmitter and 2 receivers! That makes it even easier and cheaper. Is there a way I can calculate the range of the transmitter?
 
Trial and error (experimenting) always works for me...

The link I gave you above states a range of 10 meters (~33 feet)


Jerry

You can contact us at any time on our Website: J.BAUER Electronics
 
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Alright thanks a lot to all of you!
Now I just need to find another project to use some lasers :D
Browsing through this forum really got me!
 
I only suggested using LEDs instead of a Laser due to costs..
The project can still be built using Lasers..


Jerry

You can contact us at any time on our Website: J.BAUER Electronics
 
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PickOfDestiny89 said:
What about the one above? How do I know if this one is a diode laser or DPSS? It doesn't say anything.
Click to expand...
650nm is a standard diode laser wavelength. No DPSS needed. Green and blue wavelengths (until just VERY recently) needed DPSSFD techniques because semiconductor materials that had the right properties hadn't been found until very recently. In fact, the green diode-only lasers are a brand new technology still in the development phase. However red lasers at 650nm have for a very long time existed as diode-only lasers. That's how I know your 650nm diode you've been talking about is indeed a diode laser and not a DPSS or DPSSFD laser.
 
I only suggested using LEDs instead of a Laser due to costs..
The project can still be built using Lasers..

Jerry
Click to expand...
Yeah but I want to keep the whole design as efficient as possible. I'm sure I'll find some other projects to use a laser :yh:

Making an IED?
Click to expand...
IED? Like IR LED or like a bomb? :p

650nm is a standard diode laser wavelength. No DPSS needed. Green and blue wavelengths (until just VERY recently) needed DPSSFD techniques because semiconductor materials that had the right properties hadn't been found until very recently. In fact, the green diode-only lasers are a brand new technology still in the development phase. However red lasers at 650nm have for a very long time existed as diode-only lasers. That's how I know your 650nm diode you've been talking about is indeed a diode laser and not a DPSS or DPSSFD laser.
Click to expand...
Ah good to know! Thanks!
 
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