update to laser project

[KB1LQD]

hey here is some pics from my laser project from a camera phone... if your interested let me know because its a really fun and easy project!!! its neat playing around with the lenses and stuff... at night in the rain you can see the beam downrange... next time its raining ill get a pic of that!

[KB1LQD]

transmiter

[kc7mrq]

he-ne or diode laser?

[KB1LQD]

diode laser

[kc7mrq]

What are you using for the diode current source?

[KB1LQD]

just a simple audio transformer right now running into the battery inputs of the pen..... wanna gut the diode out and rig up a real driver but with school, work, and the college application proccess, i've got no time....

[kc7mrq]

Diodes are a sensitive device. They hate to be over-driven with current. Laser diodes run in two modes. Constant Current & Constant Power. Both modes require current limit to be set carefully. There are a lot of DYI circuits to build. Make sure you pick one that will limit in-rush current (slow-start). Diodes loose their ability to produce coherent light once damaged. They become an expensive LED http://www.qrz.com/iB_html/non-cgi/emoticons/biggrin.gif .

Corey

[KB1LQC]

yep, learned that the hard way http://www.qrz.com/iB_html/non-cgi/emoticons/smile.gif Im going to build a diode modulating system soon just have to get around to it

[KB1LQD]

btw, KB1LQC's post was accually mine, I just forgot he was signed onto the computer, and i wasn'nt hihi....

[KB1LQD]

here is a new update, this is a 555 timer circuit that is Pulse width modulating the Infrared LED... Its cool, the pic is from my camera phone, the led's pretty bright but you cant see ANY light with your own eyes.....need to work on the reciever becuase there is still and occilation problem and it gets overloaded easy...

[KB1LQD]

ok, well to day Ive done alittle bit of work on the project, just cut some mudual boards and stuff, added in the stand offs. Im straying alittle bit from my orgininal design but thats ok..

In the picture in the board that is the base of the project with marked off muduals and the PWM modual board ready to be drawn and etched..... in the background is a small PWM LED test modulator with a 5V regulator I made to play around with before hand and got pretty good results.

[KB1LQD]

heres the picture

[va7aax]

cool projects . i havent looked much at this stuff, though. i may do a little playing with this

[KB1LQD]

yep, definitely alota fun, I have a one way system right now that Im rebuilding into a full duplex radio. In the picture of my last post, that modual board ontop of the insert for the chasie has been built. I put the Laser/LED Driver circuit which limits the current to the diode, ill get a picture of that when Im alittle less busy. I can range anywhere froma few Milliamps to about 50 Milliamps with a 15 turn PCB mount potentionmeter. I plane on add tempeture compensation too...

It may sound really complicated but as long as youi have soldered before and know basic electronics you'll do fine. Ill defintily get you more info, there isnt much info online but if you dig around you'll find some stuff. Anyways, start playing with LEDs and see if you can send some music across the room or something.

[KB1LQD]

Alright, heres some quick links... Id suggest build a RX first, since you can listen to all different lights and stuff... pretty neat...

anyways, If youve got any questions just ask.... And on most circuit you can use an LED instead of a laser+ if you burn out and LED its a $2 loss.... a laser diode is like $20... learned that one the hard way...

http://www.arrl.org/tis/info/laser.html
http://en.wikipedia.org/wiki/Optical_communication
http://www.repairfaq.org/sam/laserlia.htm
http://www.qsl.net/wb9ajz/laser/laser.htm

Also, check out you local library, they had a few good books on this stuff too...

[ve6wtf]

Actually make a trip to your local dollar store.
And pick up a mini laser pointer for about 1.50CDN
very cheap and long range!@

[va7aax]

Quote[/b] (ve6wtf @ Mar. 12 2007,19:17)]Actually make a trip to your local dollar store.
And pick up a mini laser pointer for about 1.50CDN
very cheap and long range!@
thanks for that , i was looking for a place to buy the laser. i am going to buy one in this week

[KB1LQD]

yep, those will definitely work, I got one at staples for like just under 20 bucks.... they work good if you tap into the power leads and modulate from there. BUT...

As you play around more you will find that the lower quality optics will bring a large beam width. basically the beam will tend to get bigger faster, so wither external optics or higher quality laser diodes are need... but I'm talking if your trying to get a really far distance... the only other concern is the current limiting circuit within the laser pointer. Although I so far haven't had problems at audio frequencies... (I'm not sure if your going to understand this...) if you're trying to send data or even send audio on a carrier frequency you will have problems with higher frequecies... at that point you would need to build your own diode driver.... not that hard, really, but don't worry about that for now, just keep it in mind if your playing around and something wont work... could be it....

ok, I didn't want to go too into it but ya, any laser pen will work at first...

Try this for a quick simple way to get audio across a room or so, just remember that because its a transformer on the power leads, you need alot of driving audio so start with a low volume input and work your way up, you might max out you audio player... ohh and as a side note, don't use an expensive MP3 player to test if its working.... bad idea, trust me http://www.qrz.com/iB_html/non-cgi/emoticons/sad.gif ... i got it fixed though... I use a $20 cd player...
http://sci-toys.com/scitoys....nicator (http://sci-toys.com/scitoys/scitoys/light/light.html#laser_communicator)

[ve6wtf]

Anyone have any idea of how a smoke detector works?
does it use the same principle?
when the communication between the two ends is lost, or degraded (by smoke) it sets off an alarm?
I will have to take one apart!

[va7aax]

Quote[/b] (ve6wtf @ Mar. 13 2007,07:31)]Anyone have any idea of how a smoke detector works?
does it use the same principle?
when the communication between the two ends is lost, or degraded (by smoke) it sets off an alarm?
I will have to take one apart!
i think you are right. i was watching a TV show on which they explain the function. the smoke particles spread into the dectector and those particles break the laser beam, which sets off the alarm. heres a link which explains it. http://home.howstuffworks.com/smoke.htm

[va7aax]

so , i can use a InfraRed LED right? , because i saw a pair of InfraRed LEDs , one is the transmitter and one the receiver. costs about 3 CDN

[KB1LQD]

yep well, theres a few types and they are explained in the link there too... the usual home detector uses inionization from a radioactive source to detect smoke, and another system uses the particles breaking the light beam, my school uses those....

Ya va7, any LED will work, Radio shack has those pair and ive got a few, one is a phototransitor and the other is a IR LED.... If you send 20 or 30 ma through the led you will NOT see anything, although if your in a very dark room and your eyes are adjusted you might see a faint red glow as some light is emited... but the accual brightness is much more, but you wont know it. Thats why IR laser are alot more dangerous for beginners because you will not knkow that its even on while looking at it and in the event that its pointed in your eyes damage can still occur!

soemthing cool to do is send some power through the IR led and take a cameraphone or most digital camera and look at the LED, it will glow really bright with a whitish blue hue. most camera CCD's are sensitive to IR as well, thats why this works, I use that to see if my LED is on or not with IR leds... lots of fun... anyways im at school so Ive gota get going...

EDIT: look at my post above with the picture of a circuit with a white glow, thats an IR LED taken with my cameraphone

[KI4QHM]

Good Job,

I wish they offered basic electronics in my school but no.

Congradulations on the good work,
Ki4qhm nick

[ve6wtf]

Got a new job today!!!

Waiter at Marci's!
8.60 an hour. plus tips
Cant wait to blow all my money on brand new gear!

[KB1LQD]

Quote[/b] (KI4QHM @ Mar. 14 2007,16:18)]Good Job,

I wish they offered basic electronics in my school but no.

Congradulations on the good work,
Ki4qhm nick
ya, I guess they used to offer it at my school but they don't anymore.... anyways, I guess that what forums like this are for, haha to ask and try things by yourself..

Oh, VA7, did you take a look at the SCITOYS website? have you gotten any LEDs or lasers?



VE6WTF, I hate to seem like the barer of bad news but was that post really necessary? I know your excited and should be.....I'm not being personal or anything, but thats not information that is very prevalent to this topic. I (and others) have gestured the same towards others in this situation....

[va7aax]

Quote[/b] (KB1LQD @ Mar. 14 2007,17:08)]Quote[/b] (KI4QHM @ Mar. 14 2007,16:18)]Good Job,

I wish they offered basic electronics in my school but no.

Congradulations on the good work,
Ki4qhm nick
ya, I guess they used to offer it at my school but they don't anymore.... anyways, I guess that what forums like this are for, haha to ask and try things by yourself..

Oh, VA7, did you take a look at the SCITOYS website? have you gotten any LEDs or lasers?



VE6WTF, I hate to seem like the barer of bad news but was that post really necessary? I know your excited and should be.....I'm not being personal or anything, but thats not information that is very prevalent to this topic. I (and others) have gestured the same towards others in this situation....
KB1LQD , i just got a laser pointer . i had a few leds which i got free but i burned them out by mistake after hooking them up to a 9 volt without resistance. i did have a look at the SCITOYS website, looks pretty simple. i do have a piezoelectric earphone , so only things needed is a resistor and the photocell resistor.

my school offers electronics from 8 grade all the way to 12 grade , but 8 grade electronics is pretty much no theory just soldering a LED blinky circuit using two 2N3904s

[KB1LQD]

hey thats still something, i bet it could get advanced... im not sure though, you'd probably know... the best thing i ever did was just sit down in my free time and read up on theory and reread to understand it... then solder random stuff together for a while... well before you hook up that laser pointer make sure you get the circuit working with an led and test the led for current and voltage, well simply a few ma's or mv's will kill the laser and make it one expensive, dim led.... The first one I burned out was because I kept adding more batteries because it got brighter, well it got really bright then suddenly died... so lol dont do that...

ya definitely use that circuit to send some audio, lots of fun, basic but works... Id say build a simple RX with a phototransitor (The one that comes with the IR LED package will work for visible light also), I built mine on a stripboard, trust me, after you build it you will walk around aimlessly for the next few hours listening to light bulbs and LED displays of microwaves and clocks.... just don't let anyone see you doing it http://www.qrz.com/iB_html/non-cgi/emoticons/biggrin.gif

hey, Ill find a book that I found at a hamfest that was pretty amazing for this stuff.... ill let you know what it is when I find it

[ve6wtf]

Quote[/b] ]VE6WTF, I hate to seem like the barer of bad news but was that post really necessary? I know your excited and should be.....I'm not being personal or anything, but thats not information that is very prevalent to this topic. I (and others) have gestured the same towards others in this situation....


Arent you just wasting more time by writing about it?
I rest my case

[KB1LQD]

so va7, hows that playing around coming?

[KB1LQD]

hey, that book is called "The Laser Cookbook", mine was printed in 1988 (Got it at a flea) and published by TAB. Good basic - intermediate stuff, starts off with some basic theory and into LEDs then into LASERs, even has plans for an interforometer, you can measure stuff to and acuracy of 1 / 316 billionths of a meter. thats small that a human hair, can wait to try once all my other stuff settles down.... found a copy on amazon.com for like 7 bucks too....

[va7aax]

i am going to start it now, couldnt do it because a lot of tests and studying . but its spring break now, so hopfully i will go to the electronics store and pick up the resistor

[KB1LQD]

heres 2 new pics, the laser is on there instead of the led now! but i haven't made the azumith/elev. device yet, just electrical tape...

[KB1LQD]

#2

[KB1LQD]

Ok, Heres an updated page on the project, We did a test of the system Here at RIT. Hope to do alot of modifications this summer!

http://www.rit.edu/sg/amateurradioclub/laserproject

[ve6wtf]

sounds like your project has come along way since your first post..
Congrats!