Laser Sensor button?

[Spacehonkey]

I'm not sure how to explain what I want exactly but I'll give it a shot. :?

For one of my future projects I want to make the PWR, RESET and DVD DRIVE buttons completely different. I was wondering if there is a way to make the buttonS to the computer into a type of laser mechanism. Another way to put it lets say you put your finger or hand in some type of hole and it brakes some type of laser and then activates whatever. I was thinking along the lines of a laser security system when you brake the beam it sounds the alarm. Well I figured this would be the best pool of knowledge to see if anyone knows of a way to pull this off.

[Guardian]

i'm not sure what you're tryina get at, but you could somthing like a touch screen?

[Spacehonkey]

Let me try to explain it in a different way then.

I want to be able to turn my computer on by sticking my finger in a tube but not really touch anything. There would be a laser of sort and when you brake the laser with your finger it would activate the power button.

[Ironcat]

If you want to build a really BIG computer than you could just buy some sort of a garage door sensor.
You could mount it inside and just leave a whole drive bay open.
Invent some gobbledeegook about the computer scanning your palm for security, insert your hand and when it breaks the plane of the beam the garage door opener could be triggered to activate the computer and you'd amaze all your friends and neighbors.

[Spacehonkey]

If you want to build a really BIG computer than you could just buy some sort of a garage door sensor.
You could mount it inside and just leave a whole drive bay open.
Invent some gobbledeegook about the computer scanning your palm for security, insert your hand and when it breaks the plane of the beam the garage door opener could be triggered to activate the computer and you'd amaze all your friends and neighbors.

Not a bad idea. I won't be building anything that huge but maybe braking open the laser safety switch on the garage door and scale that down might work.

[Airbozo]

You could do this with a led and a photo voltaic sensor (a light sensor) and a small relay circuit. Finger breaks the beam, relay makes contact...


EDIT: Exactly like the sensors that go off when you enter a store. Break the light beam, bell rings...

EDIT2: Similar to this circuit although it is just a light sensor circuit;
http://www.uoguelph.ca/~antoon/circ/sensor2.htm

EDIT3: More info here (some info that just6 does not apply too);
http://ourworld.compuserve.com/homepages/Bill_Bowden/homepage.htm#menu

EDIT4: and even more;
http://home.cogeco.ca/~rpaisley4/PhotoDetectors.html

[Spacehonkey]

Thx, Airbozo, I think that might actually work for what I have planned.

[Guttenaffe]

not that hard if you use the 5VSB

You don't really need a "laser" but an LED with an photodiode (or maybe a photoresistor will work too) connected to the control LED of a optical isolator. As follows:

http://img236.imageshack.us/img236/6443/ledswitchdu9.gif

As long as the photodiode is saturated to ~0Ω the photo you have dual 0V across the operating LED of the optical isolator. If you block the saturation to the photo diode then current can power on the 4N25's LED and trigger the its transistor to operate as your switch. This is at most a $5 circuit...

[Spacehonkey]

I chose to try and make the light activated switch by following these schemetics

http://www.uoguelph.ca/~antoon/circ/sensor2.htm

I went to RadioShack and bought all the stuff I needed to complete it but I forgot to get a 12 Vdc pwr supply.

Does anyone know of a good place to buy a cheap 12Vdc pwr supply?

I called RadioShack back and the cheapest one they have is $43. Maybe I should just wire some AA batteries into series and use that. Yeah maybe I'll try that instead.

Oh yeah also has anyone out there ever messed around with a Light Dependent Resistor?

I want to test out the Light Dependent Resistor to see if it was good so I started to mess around with it and hooked it up directly to a 6Vdc pwr source with nothing else to interfer with it and used a meter to get it's measurements. Now maybe I'm all jacked up in the head but when you shine a light on the resistor shouldn't it NOT let any power pass through it or at least decease the voltage. When I did it I shined the light directly on the Light Dependent Resistor and nothing changed. I still got 6Vdc coursing through it just like before I put the light on it. If I'm doing this wrong can someone please explain how it should work.

[Drum Thumper]

Does anyone know of a good place to buy a cheap 12Vdc pwr supply?



Would a wall wart work? 15 buck at the most at your local wally world.

[Drew]

**not an electrician**

Does a light dependant resistor work the other way?

Put your finger over the light reciever and see if it stops the flow.

I could be wrong...

[DaveW]

+Rep for Guttenaffe and Airbozo, great information!

-Dave

[Spacehonkey]

Would a wall wart work? 15 buck at the most at your local wally world.

Wal-Mart $15, ummm, didn't think they carried stuff like that. I'll have to give them a shot. I'll go run down to the nearest one after I get off work today.


**not an electrician**

Does a light dependant resistor work the other way?

Put your finger over the light reciever and see if it stops the flow.

I could be wrong...

I thought that would work too but it didn't change anything. I think I'm going to try and surf the web today, if I have any free time, and see what kind of info I can find.

+Rep for Guttenaffe and Airbozo, great information!

-Dave

Ohhh yeah, how could I of been so forgetful. +Rep to Gut & Air for the helpful info. Sry I didn't give it to you guys earlier.

[Spacehonkey]

OK I'm a complete retard. Ignore the part in my last post about not getting the LDR to work.

I made a 12Vdc pwr supply out of a 9V & 2 AAA batteries. I wired it like this, just to see if it'll work.

+-----resistor-----LDR-----resistor-----LED------

Now whenever I put my finger over the LDR the LED dims. Now the next step is where I get all mixed up in the head. Now the next step would be to wire in the relay but I'm doing something completely wrong because nothing works now. I'm not sure I have a complete understanding of all the wiring. I didn't think this would confuse me but I've never really worked with circuit boards before. I know I had to of wired it up wrong. I'll play around with it this weekend and see it I can figure it out.

[armadilloben]

You could do this with a led and a photo voltaic sensor (a light sensor) and a small relay circuit. Finger breaks the beam, relay makes contact...


EDIT: Exactly like the sensors that go off when you enter a store. Break the light beam, bell rings...

EDIT2: Similar to this circuit although it is just a light sensor circuit;
http://www.uoguelph.ca/~antoon/circ/sensor2.htm

EDIT3: More info here (some info that just6 does not apply too);
http://ourworld.compuserve.com/homepages/Bill_Bowden/homepage.htm#menu

EDIT4: and even more;
http://home.cogeco.ca/~rpaisley4/PhotoDetectors.html

smart idea man but i think that it may be cheaper for him to use a Photoresisitor its basicly the same thing but he could have it light or dark activiated so he could like just wave his finger over it and it could interupt the circut and turn the pc on... i think

[Spacehonkey]

Just a quick update. Since this laser switch problem I'm having is a circuit problem and not so much a modding issue, even though once I figure it out it will be used on a future mod of mine, I've asked for help on a circuit board forum. Whenever I fix this I'll post back here with an update. Thx for all the help guys.

[DevilTeck]

Just a quick update. Since this laser switch problem I'm having is a circuit problem and not so much a modding issue, even though once I figure it out it will be used on a future mod of mine, I've asked for help on a circuit board forum. Whenever I fix this I'll post back here with an update. Thx for all the help guys.

Spacehonkey,
really good idea, let me see i can illuminate the situation(every pun intended :D ) in a series circuit(which you have) resistors restrict or limit the flow of current in the circuit, now a LDR has a very high resistence when dark(usually 100k ohms or higher) which will cut most of the current to the circuit. Now when light illuminates them there resistance is dropped to near zero allowing current to flow. Hope this helps. also check this out http://www.technologystudent.com/elec1/ldr1.htm

[Spacehonkey]

Thx for the info, DevilTeck. My current problem isn't with the LDR, that works just fine now. I just didn't understand how they worked when I first started this project but now with the help of people like yourself I'm just a little bit smarter with this stuff. My problem now is the LDR isn't influencing the output voltage from the OpAmp which should control the transistor which in turn engerizes/deengerizes the relay.

[Spacehonkey]

I finally got the whole thing to work.:D I was using the wrong transistor the whole time. I was using a PNP when I should have been using NPN. Now the whole thing works great. I need to buy a new circuit board since the one I was using has a ton of solder all over it. Hopefully by the end of the week I'll have the circuit card built up and then I'll use an old computer a friend just gave me last week to see if this will work like I intended.

[Spacehonkey]

Anyone here know how to make a PCB design out of a wire schemetic?

[DevilTeck]

Anyone here know how to make a PCB design out of a wire schemetic?

i do pcb design with PCAD but as in free software not sure try the trusty google(i can try to design something for you if you want)

[Spacehonkey]

i do pcb design with PCAD but as in free software not sure try the trusty google(i can try to design something for you if you want)

If you can that would be great. The setup I'm using is shown on the link http://www.uoguelph.ca/~antoon/circ/sensor2.htm. I'm not sure how that PCB designs work but I would like it as small as possible since I'll need 3 of these setups in all in tight area.

I tried google and come up with http://www.new-wave-concepts.com/ed/circuit.html but on the demo it won't let you convert the schematic into a PCB setup.

[Spacehonkey]

I couldn't wait.:p So I opened up one of the spare computers I have and took the pwr button wires off. Hooked them up to the relay. I had to use a external 12Vdc battery for the main LDR circuit board. Then I said a quick pray to the god of modding, that would be you Crimson Sky just joking:D , and than I covered the LDR sensor with the shadow of my hand and it powered up. Man it felt cool as hell to hear that relic of a computer spoiling up.:banana: Then I ran my shadow over the switch again and that mother powered down with no problem. Now the only thing I need to work out is to set the LDR sensor along with the LED light back into a recessed hole so that the room light won't affect it. I wouldn't want the computer to turn on/off ever time I enter/leave the room and turn the room light on/off. Oh yeah I'll explain later exactly what mod I plan on using this light activated switch on after I complete my current Monitor Mod.

[SgtM]

Outstanding work man!

:pics:

[DevilTeck]

I couldn't wait.:p So I opened up one of the spare computers I have and took the pwr button wires off. Hooked them up to the relay then I shot one of the spare connectors from the computer's pwr supply and found out that it has exactly 12Vdc going through it so I hooked that up to power up the LDR circuit board. Then I said a quick pray to the god of modding, that would be you Crimson Sky just joking:D , and than I covered the LDR sensor with the shadow of my hand and it powered up. Man it felt cool as hell to hear that relic of a computer spoiling up.:banana: Then I ran my shadow over the switch again and that mother powered down with no problem. Now the only thing I need to work out is to set the LDR sensor along with the LED light back into a recessed hole so that the room light won't affect it. I wouldn't want the computer to turn on/off ever time I enter/leave the room and turn the room light on/off. Oh yeah I'll explain later exactly what mod I plan on using this light activated switch on after I complete my current Monitor Mod.

cool glad it worked like you want it to,so i take it you don't need a pcb layout? if you do just send me(e-mail) a list of exact part #'s and i can whip something up in about a hour or two.

[Spacehonkey]

Outstanding work man!

:pics:

Oh don't worry I'll play around with my video camera if I get a chance this weekend (wife is throwing a Easter Party). Then see about putting it on YouTube or something.

[Spacehonkey]

I've video taped the sensor in action with my DCR-DVD92. If you're not fimilar with this camera it burns the videos directly to a mini dvd disc. My problem is I have no idea how to transfer the video from the disc to a format I can upload to YouTube. As you probably can tell I've never tried to do this so any advice or links you guys can give me would be helpful.

[Spacehonkey]

I said screw the dvd video camera and used my web cam. I did a quick edit job, threw in the first audio track I could fine from a DJ buddy of mine and I just got done uploading it to YouTube so here you go. Enjoy :D

RP2Bmw_qvNo

[Spacehonkey]

I took some still shots of the test switch I made to go along with the video I posted earlier.

Just an overall look at the switch.
http://i80.photobucket.com/albums/j189/spacehonkey/Computer%20Mod/Case/Case.jpg

Test setup in a toilet paper roll.
http://i80.photobucket.com/albums/j189/spacehonkey/Computer%20Mod/Case/LtSwitchA.jpg

Closeup at a different angle
http://i80.photobucket.com/albums/j189/spacehonkey/Computer%20Mod/Case/CloseupofLtSwitchA.jpg

Inside the computer. Breadboard setup (yes I know it's a mess). I did find 5Vdc power source on the motherboard to power up the LED but I still have to use an external 12Vdc to run the board. I would like for this setup to run completely off the PSU though.http://i80.photobucket.com/albums/j189/spacehonkey/Computer%20Mod/Case/BreadBoardSetupA.jpg

I'm currently trying to build up a PCB design with the help of others on this forum and then I plan on using a photo-etching method to make a professional looking circuit board. If that doesn't happen then I'll just resort back to using a plain Jane generic board like this one.
http://i80.photobucket.com/albums/j189/spacehonkey/Computer%20Mod/Case/BoardSetupRough.jpg

[DaveW]

Haha...brilliant. What are you going to use this for? :D

+Rep for the ghetto loo roll tube mod!

-Dave

[Spacehonkey]

Haha...brilliant. What are you going to use this for? :D
-Dave

Well I was going to wait until I finished my Monitor Mod before I posted anything about my case mod. I didn't want you guys to think I was all talk and no action but what the hell. I just posted the thread on my case mod idea,Barebone Case (http://www.thebestcasescenario.com/forum/showthread.php?t=7461), that this LDR switch was designed for. Hope you guys enjoy.

[gaz_the_chav]

Wow I want to make one! Please can you list all the components (including the ohms and stuff) for me. I have looked at that diagram but can't work out what I do and don't need.

Thanks alot! +rep for brilliant invention!

-gaz

[Spacehonkey]

Here is a list of all the components I'm used:

NPN Transistors (15-Pack) (http://www.radioshack.com/product/index.jsp?productId=2062586&cp=2032058.2032230.2032279&parentPage=family)

LM741CN Operational Amplifier (8-Pin Dip) (http://www.radioshack.com/product/index.jsp?productId=2062547&cp=2032058.2032230.2032279&parentPage=family)

10K-Ohm Horizontal-Style Trimmer (http://www.radioshack.com/product/index.jsp?productId=2062301&cp=2032058.2032230.2032275&parentPage=family)

1N4742A 1-Watt Zener Diode (http://www.radioshack.com/product/index.jsp?productId=2049725&cp=2032058.2032230.2032269&allCount=21&fbn=Type%2FDiodes&f=PAD%2FProduct+Type%2FDiodes&fbc=1&parentPage=family)

12VDC/1A SPDT Micro Relay (http://www.radioshack.com/product/index.jsp?productId=2062481&cp=2032058.2032230.2032277&allCount=26&fbn=Price%2F%244.00+-+%245.99&fbc=1&fr=StorePrice%2FRSK%2F00000400%2F00000599&parentPage=family)

10K Ohm 1/4-Watt Carbon Film Resistor5 Pack (http://www.radioshack.com/product/index.jsp?productId=2062347&cp=2032058.2032230.2032267&fbx=0&allCount=100&fbn=Type%2F1%26%23047%3B4+Watt+Resistors&f=PAD%2FProduct+Type%2F1%26%23047%3B4+Watt+Resisto rs&fbc=1&fr=StorePrice%2FRSK%2F00000000%2F00000399&parentPage=family)

1K Ohm 1/4-Watt Carbon Film Resistor5 Pack (http://www.radioshack.com/product/index.jsp?productId=2062343&cp=2032058.2032230.2032267&fbx=0&allCount=100&fbn=Type%2F1%26%23047%3B4+Watt+Resistors&f=PAD%2FProduct+Type%2F1%26%23047%3B4+Watt+Resisto rs&fbc=1&fr=StorePrice%2FRSK%2F00000000%2F00000399&parentPage=family)

470 ohm 1/4W 5% Carbon Film Resistor pk/5 (http://www.radioshack.com/product/index.jsp?productId=2062342&cp=2032058.2032230.2032267&fbx=0&allCount=100&fbn=Type%2F1%26%23047%3B4+Watt+Resistors&f=PAD%2FProduct+Type%2F1%26%23047%3B4+Watt+Resisto rs&fbc=1&fr=StorePrice%2FRSK%2F00000000%2F00000399&parentPage=family)

That's it any questions don't be afraid to ask.

[gaz_the_chav]

Thankyou very much!

-gaz

[gaz_the_chav]

So where is the LDR in the parts list then cos this is really confusing me lol!

-gaz

[Spacehonkey]

Oh sorry forgot about the LDRs. I couldn't find them listed on the RadioShack web site but I know they have them. The model # is 276-1657, I bought a pack of assorted LDRs there. Any one of them will work. I personally used the smaller one.

[Drew]

I can't believe it actually worked :O:O:O

+rep that man.

[gaz_the_chav]

Oh sorry forgot about the LDRs. I couldn't find them listed on the RadioShack web site but I know they have them. The model # is 276-1657, I bought a pack of assorted LDRs there. Any one of them will work. I personally used the smaller one.

Thanks dude I seriously thought i was really spastic there lol!

Cheers dude I will let you guys know how mine goes.

-gaz

[Spacehonkey]

Thanks dude I seriously thought i was really spastic there lol!

Cheers dude I will let you guys know how mine goes.

-gaz

Have fun. I would like to see how you decide to use it.

[vidas7de7jesus7]

hehe, if you were a terrific aim, you could turn your computer on with a spitball or something. Practice your paintball aim by turning on your computer, etc. Fun stuff.

[Spacehonkey]

hehe, if you were a terrific aim, you could turn your computer on with a spitball or something. Practice your paintball aim by turning on your computer, etc. Fun stuff.

LOL, That would be interesting.

[Spacehonkey]

I posted this question before in this thread but the person who said they could make me a PCB design for a circuit board never got back in touch with me so I'm asking again for some help from anyone.

Can anyone here make a PCB design out of a wire schemetic?

I would like to DIY a circuit board. I can order a kit for around $50 to make a professional looking board but I don't have a way to make a PCB design. I can order one off the net for $50-$100 but that's way to much money for something so small.

[Spacehonkey]

Well I found a program for free to help me design a PCB. I made a file with multiple boards on it and went to Kinko's and printed the file to a transparent sheet. I went to Fry's and bought the UV light exposure kit and the Developing/Etching kit. Did everything like I was suppose to do and this is what came out.

http://i80.photobucket.com/albums/j189/spacehonkey/Computer%20Mod/Case/IM002914.jpg
http://i80.photobucket.com/albums/j189/spacehonkey/Computer%20Mod/Case/IM002912.jpg

I know the glare on the pix annoys me too. Guess I need to work on my photography skills. I'm not sure why the copper streak is on the bottom part of the board as well. Good thing I only need 3 of the circuits for my project. Overall I don't think I did that bad for my first attempt. I was on a natural high for a couple hours after I did this.:D

Well now for the bad news.:( Since I'm also a noob at doing anything with circuit boards I found out when I was soldering the components on the card that when I was did the PCB design I had some of the contacts upside down and backwards. So when I tried to put the relay on the board the contacts wouldn't fit because the holes were backwards.:mad: Plus I forgot to incorporate the small circuity for the LED light. So I've got to go back and redesign the PCB and do the whole developing/etching thing again.

[DaveW]

Ach, don't let it get you down dude. That looks Ace and i'm sure you'll get it right this time.

Where's the fun in getting everything right first time anyway, eh?

-Dave

[Spacehonkey]

I need to know which PCB design is better or will they do the exact same thing. I have made two designs they're identical except for a couple of spots.

The first one is straight shot from one component to next one.
http://i80.photobucket.com/albums/j189/spacehonkey/Computer%20Mod/Case/StraightShot.jpg

This next one gives a little space between the component and the track with the power.
http://i80.photobucket.com/albums/j189/spacehonkey/Computer%20Mod/Case/Space.jpg

[DaveW]

The second one looks like it will be easier to do, but look out-the top to the far right, that track comes awfully close and it would be very easy to short that when soldering.

-Dave

[DevilTeck]

Spacehonkey,
Sorry was really busy realeasing new code for equipment at work, but i was the one that offered to make you a pcb. it's about midnight here so i'll look at the threads again tommarow and get back to you. sorry again for not answering you.:D

[Spacehonkey]

That's cool, I thought you might of been busy with work or something. I did find a program that I could make a PCB design but since I know very little I would still like to see what you can come up with. If you backtrack and see some of my other posts in this thread then you can see that I've made it all the way to actually making a circuit board. Even though it turned out totally awesome I messed up on the original design and I have to start all over again. So before I etch a new board and possibly waste another circuit board I would like to compare your design with mine and see were I went wrong. The main mistake I made was I put the post for the relay in the wrong spot so when I went to put it on the board it didn't fit.