I love love LOVE that you did a video on a project that DIDN'T work. That's such an important part of the process and I feel like people get discouraged when their projects don't work rather than just getting up and trying again, like your awesome attitude at the end.
This engineer is terrific. He knows design and process for electronic circuits very well. He is concise, and accurate with his facts and process. His videos are terrific!
+sans you can't find neodynium magnets since dvd players roughly. i'm sure i'm wrong but in some old CD players i've never seen them. Or i was really blind.
Actually gives me cause for puzzlement but otherwise HIGHLY delighted that they do. I could spend a week at our recycling plant saving a fortune in bits, pieces and perfectly usable components Just today picked up two fully functional Makita drills, both two speed and one a hammer drill also. Well used but otherwise look in pretty good condition, only missing batteries - big deal - get on eBay for less than £25 for TWO!. Don't need the standard chargers as they f**k up batteries big-time. Have my own which doesn't! Also collected three PC's c/w psus and some older DDR400 memory (I needed some for an old shoe-box PC too), a few DVD RW drives (hence being here) LOADS of SMD components I can recover off these if the boards don't work. Amazing stuff people chuck away. A few fans (I always refurbish fans whenever I can. A few drops of 3-in-1 oil onto the bearing from behind the stopper - or sticker - work it in and bingo. I have one fan that I've re-lubed twice and it's still going after 16 years!! Quiet too.
Loved your comment at 2:05 " .... and carefully removed the two diodes ..." And then you take you pliers - jam them behind the diode - and it goes flying off the screen !! LOL !!!
I appreciate your failed attempts at worthy projects. They show humility and design acumen. It’s awesome to watch a video more concerned with the process than the outcome.
Don't know how I haven't found you untill a week or so ago, but so very glad I have! makes me want to get into playing with electronics all over again! thank you sir!
They make precision voltage references for small amounts of current. Basically you can use it similar to the schematic with a few changes. Constant voltage across a resistor = constant current. The precision voltage references are used in IC's like LM34 and LM315. The LM1117 is a low voltage high efficiency voltage supply that would be ideal to run this kind of application in addition with the voltage reference and a battery pack. Nice application and tutorial.
For the future, there were likely 2 additional neodymium magnets that you may have missed...depends on the drive. They are REALLY TINY magnets, too...about 3mm L x 2mm W and less than 1mm thick. They should be attacked to a small movable coil that further stabilize the LASER beam emitter based on optical feedback from the disc. This helps the drives achieve much higher speeds than before.
When I was a teenager I thought about how cool that would be to do. Thanks for answering that question by showing how nothing visibly interesting happens.
The Technics SL-P1200 CD player had a particular point of failure in the CD door switch. The switch was a blade that contacted copper fingers, meant to prevent the player from operating whenever the door was open, because potentially a user could look right at the laser. But it was a crude design, so we had to replace them regularly.
GreatScott! I am an electronics amateur and I know the high power laser diode is not that price cheap, I mean the one you can put something on fire. You proved fake things all around in youtube. I love your video - clear and professional.
I was looking for some other site and seen your home made stereo box ,so I watched the video ,anyways I could watch this all day my grandfather was an inventor one of the things I was told he invented was the thermostat inside your furnace ,my dad. invented lots of different types of tools for sears and my uncle's are inventors also they do the same things you do thanks for your time and videos I subscribed ,love it .
for an episode of hacked you could build a dvd drive mini laser engraver/plotter. You could use 2 dvd drives (already got one from the drive you took apart for the laser), a servo (for the plotter, if you go that route), 2 stepper drivers and a arduino, it would be a fun project to see
I just watched this video and immediately dismantled 7 of the 10 dvd drives I had sitting. I would love to see a tutorial on how to use multiple diodes simultaneously, I would imagine that many others may want to do that also.
I would think you could use a high current pulse to drive the laser much harder. You can do this with infra red LEDs when you need to send the light over a longer distance. The data sheets will tell you how much current and for how long of a pulse to use.
It was a project that didn't provide a result that was expected NOT a failed project. MUCH can be learnt from this video even if it didn't succeed in giving the expected result. Any time something can be learnt (without killing or seriously injuring yourself) is useful, therefore not a failure.
If the forward voltage of the diode is less than 3V, then it is the IR diode. It still gives off visible red light at, so beware - you can easily blind yourself, thinking it is just a dim red diode.. An LM317 is sufficient if you keep the input voltage not far above 7V. 500mA is too much for an unknown diode. Don't go above 400mA MAX (even this is pushing your luck), and the 1/4W pot will handle it fine if you put an appropriate series resistor before it (the voltage drop over the pot will be low (P=V*I) . Disconnecting the diode from the constant current source and reconnecting it while under power will kill the diode.
There are at least two different IR diodes 840nm and 910nm the 910nm should not give any visible light (at least for regular diodes tho not laser ones)
This kind of diodes start to burn at 150-200mA and you normally should run them between max 300-400mA. I think he did blow the diode up, which can happen really quickly when he connected the diode to an charged capacitor, like the one of the output on the power supply. You cant really see this, the diode just gets dimmer and a powerful diode like that one could maybe look like an very weak laser diode after that. Or he maybe overheated the diode because the diode did not have a "very tight fit" in the housing that it normally should have. Thats the reason why you "never" should use a drill to get the old/standart diode out of the housing. Btw. you could even use a driver with just two parts like this one is.gd/OOSwlC just replace the resistor with an small potentiometer ;)
Seems like either your laser diode is damaged or the drivers voltage isn't enough. Seems like the driver delivers the right amount current to a test load. But Remember just like LEDs laser diodes have a forward voltage so you just not have enough voltage to run it. It kinda looks like you might have an infared laser diode
I know this is an old video, but I am trying to find a GOOD laser diode driver circuit. You said you were going to make a better circuit in another video and I can't seem to find it. Did you ever make that video or not?
Nice video. I need a constant current source around 1 miliamp and made it with a LM317.I did not know this was an inefficent way to do it, so I will be looking out for your more efficent constant current source. Thanks.
Actually, how I look at this "infrared diode" through the gap, she looks like Mitsubishi LPC815 (red open can laser diode). Have you tried to free both diodes or just the "burnt" one? (And yes, I know that that was 5 years ago, but I'm just interested :P)
Had the same problem. I've built everything but didn't work out too well. I was using the laser diode from an 8X laptop DVD-RW drive. Aparently you need at least an 16X drive up to 22X or more X drive because that dictates the power of the laser diode. Hope this helps. Cheers :)
You must unfocus the laser to have it burn, and that will not take your eyesight, maybe the ultraviolet one, but that red one is less that 5mw, right within the safety of the blink reflex which prevents damage to the retina
mit wie viel Spannung betreibst du die konstantstromquelle die du gebaut hast ? ich würde mich freuen wenn ich eine schnelle Antwort bekomme :D bau das nämlich nach für die schule ... als Projekt für die Vorarbeit meines Abiturs... danke schon im voraus
DANG! that was such a informative and disappointing video. Ripping apart old HDs and CD/DVDs. Saw the laser and got excited!!! A Google later and GreatScott! FANTASTIC! ...oh well. Thank you, saved me gobbs of time. You are the BEST!!!
I seriously love these videos. I have the same habit of repurposing old parts for new projects. I also enjoy the fact that you don't try to hide or gloss over when you don't get the end result you were hoping for (aside from a working circuit, which always happens). By the way, your English is excellent! Even if you do pronounce a few words in a strange way, I can still always understand everything that you say. What's your native tongue?
what xan i use in plce of the part you bought? to focus it? any idea? and thank you so very much m you are the best !!! For guys like me i really appreciate all your explanations no matter how petty they may seem to you. thru hemp me understand.
hi scott! i really like your videos, thank you. did you ever make the video showing the more efficient constant current circuit? i need to make one and would love to apply the less power hungry option.
4:21 Mosfets are voltage operated devices not current … that 1k resistor isn’t necessary at all… it works of course but it won’t make any difference to the amount of drain current because it’s the voltage rather than the current on the gate that enhances the channel between drain and source… in other words it’s a voltage dependents resistor. Also there is no inrush current, inrush current is initial current that meets high capacitance and it’s the surge that is required to provide that initial peak in demand that is what’s called inrush current.
lasers will have a focal point of concentrated energy.. did you try adjusting the distances and wait a few seconds at each distance to see where that is? It's probably fairly close up, since it is used to scan disks at close proximity
I am not sure if adding the 1K resistor between the op-amp and the gate of the power FET was an improvement. You said : "to reduce the inrush current", but the gate of a FET transistor appear like a very small capacitor. Once charged, there is no flow of current. Applying a DC voltage to the gate produce no measurable current. Normally, you want the lowest impedance possible for the control of the gate so that you can charge/discharge that internal capacitor as fast as possible. You want to operate the transistor in saturation mode : fully conducting or non conducting. If the transistor operate in between these extremmes, it will dissipate heat.
Dude, use a heat gun/blow dryer to remove the diode, when ive pulled those magnets from CD read/write heads it works well with bit of heat, plus breaking the coating on those magnets isn't great exposure over time, but with heat they slide off
GreatScott! 230ma is the nominal current, anything above you'll risk damage the laser and it will turn to a very weak laser, even a short over current mistakes like adding 0.01uF might 🔥 burn it.
~☆ XzCraftP ☺♂ It does work. A diode from CD-RW will burn matches easily. But since it is infrared, it's very dangerous because the beam is INVISIBLE. Around 180mA will do just fine.
Where do you get rid of all the electronic (-less) waste then? Can you throw it into the trash once you have gotten out enough of the electronics? what when any electronics are left over, is it okay to throw them into the trash? (small PCB's for example)
Low power lasers are good for generating interference patterns and bouncing off mirrors on speakers to make trails on the wall (always away from people) and for laser modems... probably safest through optical fiber? Hmmm... how many bits in a bundle?
Isn't your constant current source is equally inefficient because it is also a linear regulator? The opamp is in a voltage follower configuration. Thus. the mosfet is used as a variable resistance, converting excess power to heat in the same manner as the LM317. You can add two extra resistors to the MCP602 to turn it into a comparator circuit with hysteresis. This would turn the converter into a very crude switch-mode converter. The trick is to only allow the mosfet to be either fully on or fully off so it does not dissipate any power. Smooth out the output by adding an LC filter if you want to be fancy.
TIP: Peanut-butter removes oils, glues, tars. Chunky versions effectively helps this further, steel-wool does wonders. Polish with some tooth-paste and warm water
NOTE: That isn't paste that silicone, very ineffective are heat dissipation. Thermal Grizzly has some of the best, Kryonaut or K-Extreme is recommended for best results
Yes, you need to be extremely careful, those protection glases should be a must, as I experimented with it I broke the lens in the diode and the laser light came out just everywhere out of the diode and for a short time I got a little into one of my eyes, my heart started to beat like crazy, it was really a shock but I had luck because probably the laser isn't powerful enough without its lense. I can just say to every beginner: Do not touch it if you have any doubts, except of you have all that is needed to protect you, no matter what it's about.
I love the Great stuff videos. lol Everytime I hear him say "See a screw, remove a screw" and "That's Bullshit" I start cracking up... Very informational and I've learned a lot from this dudes videos. :-P
Heey, how did you desolder the flexible PCB's? I've tried to do the same with an old dvd player I've found, but they didn't seem to get loose at all, and I ended up ripping out a pin... :I :? :P
I think we all are waiting for a video how to make an efficient Constant Current Source. I have several 700mA leds that need to have a CCS driver but need to be controlled it with a micro-controller.
