|
Gotta be something inside that battery or connector. Would be a great party trick. (I party with nerds.)
|
#
?
Dec 14, 2012 05:44
|
|
|
|
| # ? May 9, 2024 18:51 |
|
|
That connector does look kind of thick, but I'm not sure how he'd accomplish that even with logic 
|
|
#
?
Dec 14, 2012 05:52
|
|
|
Well it's almost certainly a preprogrammed, timed sequence which he's just synchronizing his finger to. He's not actually controlling anything directly. A 9V battery case has plenty of room for whatever sort of driver circuitry. But I can't think of how each LED is controlled by the electronics, unless he's actually able to fabricate LEDs with simple integrated circuitry. LEDs with built in flashing controllers exist, but those can't replicate this behavior.
|
|
#
?
Dec 14, 2012 06:41
|
|
|
^^^ Edit ^^^ He also somehow altered LEDs with SMD diodes in another video. I'm sure this isn't timed and is actually responding to his touch. When you touch the leads I imagine resistance and capacitance would change, right? If you know the values of the untouched loop then it should be easy to figure out where it's being touched. Especially if you used AC rather then DC. (Which is what he did in that 1 LED 2 Switch video.) The interesting bit is that he claims it's a fully analog circuit, no CPUs (which I take to include any sort of digital processing). The last time I designed analog circuits I was 12,
|
|
#
?
Dec 14, 2012 06:46
|
|
|
^^^ edit, he says it's all analog? Hmm... wonder how he responded to the touch sensing then.ANIME AKBAR posted:Well it's almost certainly a preprogrammed, timed sequence which he's just synchronizing his finger to. He's not actually controlling anything directly. A 9V battery case has plenty of room for whatever sort of driver circuitry. But I can't think of how each LED is controlled by the electronics, unless he's actually able to fabricate LEDs with simple integrated circuitry. LEDs with built in flashing controllers exist, but those can't replicate this behavior. He's got an earlier video involving switches, and that's been been explained, I assume this is just a fancier, craftier version. The older one had an AC circuit in the battery, with a smaller battery inside. Two of the LEDs had opposite polarity to each other, with a hidden diode across each one in opposite polarity, so the AC would illuminate both. If you opened a switch in series that had another diode in parallel to it, the opposite LED would go out. Put two switches in series, and you can turn off either LED. The third LED involved a capacitor filtering the AC somehow but I can't remember the details... it might have involved blocking a DC component or something. I imagine for this third one, there's a microcontroller with two three-state output pins, and he can do capacitive sensing on the wire as well, and has the same bits in parallel with the LEDs. It seems like if you were fairly careful you could solder surface mount LEDs, diodes and/or caps together and them put them in plastic that looks like a through-hole LED. In the old circuit he was just crafty about hiding the extra parts under the LEDs.
|
|
#
?
Dec 14, 2012 06:51
|
|
|
Base Emitter posted:^^^ edit, he says it's all analog? Hmm... wonder how he responded to the touch sensing then. He says: This is an analogue design (no used CPU) So he either means all analog or he means no microprocessor. If he means no microprocessor, flipflops and logic gates are still on the table.
|
|
#
?
Dec 14, 2012 07:05
|
|
|
This is actually a really fun little puzzle to solve. I love stuff like this. (I also love this thread. I wish I would have found it before now. Hell, I didn't even realize we had a DIY section!  )
|
|
#
?
Dec 14, 2012 07:09
|
|
|
I remember seeing an earlier circuit by this guy on hackaday along with the howto: http://hackaday.com/2012/01/27/followup-troll-physics-solved/ I imagine the new one is similar with a lot of impressive soldering crammed in the battery connector. His other videos are pretty cool too. Plus he posts solutions!
|
|
#
?
Dec 14, 2012 07:39
|
|
|
priznat posted:I remember seeing an earlier circuit by this guy on hackaday along with the howto: http://hackaday.com/2012/01/27/followup-troll-physics-solved/ To me his soldering skills make me more  than the circuitry.
|
|
#
?
Dec 14, 2012 12:55
|
|
|
timb posted:^^^ Edit ^^^ It's very unlikely that it's actually touch sensitive. It's battery operated, and the circuit isn't earthed, meaning that there's no current return path for the touch to cause an actual change in capacitance. Unless he's doing something like time domain reflectometry, I'm convinced the touch sensing is fake. I mean look at how precisely timed all the finger taps are.
|
|
#
?
Dec 14, 2012 14:12
|
|
|
ANIME AKBAR posted:It's very unlikely that it's actually touch sensitive. It's battery operated, and the circuit isn't earthed, meaning that there's no current return path for the touch to cause an actual change in capacitance. Unless he's doing something like time domain reflectometry, I'm convinced the touch sensing is fake. I mean look at how precisely timed all the finger taps are. I don't think it's fake - if you're going to do that you might as well just edit the video. I suspect he's making use of some parasitic effects to start/stop an oscillating circuit. If you notice, he's always touching one of the battery leads with his other hand whenever he's turning an LED on or off. This could load down an oscillator, or cause it to skip to a different harmonic. While I don't think he's using a micro, that would make it even easier to detect a capacitance change. If he has three different oscillating frequencies, and appropriate filters around the LEDs, he could control them independently. No tricks, other than an incorrect schematic, some augmented parts, and exploiting some analog "side-effects." In a way, it reminds me of another, older, electronics puzzle. Take a common NPN transistor, like a 2N2222 or 2N3904. Connect a resistor in the 100-1K range to the emitter and a 9V battery between the base and end of the resistor, but reverse biased (negative on the base and positive on the resistor). What is the voltage on the collector? SnoPuppy fucked around with this message at 00:21 on Dec 15, 2012 |
|
#
?
Dec 14, 2012 18:50
|
|
|
SnoPuppy posted:In a way, it reminds me of another, older, electronics puzzle. Trick question? Max Veb on those parts is 6V. 
|
|
#
?
Dec 15, 2012 00:05
|
|
|
Boy With Stick posted:Trick question? Max Veb on those parts is 6V. Oh, I forgot to mention that you should have some resistance on the emitter. Something in the range of 100-1K should be good. Try it on a breadboard and measure the collector with a DMM. SnoPuppy fucked around with this message at 00:21 on Dec 15, 2012 |
|
#
?
Dec 15, 2012 00:13
|
|
|
I am fixing a speaker for a few friends of mine, and this is what the crossover looks like: Needless to say I will need to replace a few components. This is the board in the matching speaker (sorry it is rotated 180 degrees):  The large inductor in the center looks like this under that piece of wood:  I am all set with the markings on the capacitors and resistors, but I don't know how to find suitable inductor replacements. Can anyone here help me out? The inductors that need to be replaced are marked: --- 01020797 1.80/18 --- 0050697 .30/18 --- 00061797 .40/18 ---
|
|
#
?
Dec 15, 2012 23:19
|
|
|
armorer posted:Needless to say I will need to replace a few components. It might not be as bad as it looks. Seems like a single capacitor burst, and the electrolyte spilled out and sorta burned around heat-the resistor and the area around it, as well as the inductor itself. But the "enamel" on the inductor might still be intact, and it might be ok
|
|
#
?
Dec 15, 2012 23:49
|
|
|
Slanderer posted:It might not be as bad as it looks. Seems like a single capacitor burst, and the electrolyte spilled out and sorta burned around heat-the resistor and the area around it, as well as the inductor itself. But the "enamel" on the inductor might still be intact, and it might be ok The two small inductors might be ok. The large one looks pretty bad from the side though. I would be surprised if the enamel didn't melt. It looks like it all melted together and even ran down the side a bit. At the moment I am planning to replace the three resistors over the charred areas, obviously the cap that exploded, and the three charred inductors.
|
|
#
?
Dec 16, 2012 00:04
|
|
|
armorer posted:The two small inductors might be ok. The large one looks pretty bad from the side though. I would be surprised if the enamel didn't melt. It looks like it all melted together and even ran down the side a bit. If I had to guess, I'd say that the first number is the value in mH and the second number is the wire gauge. So your inductors would be 1.8 mH/18 ga 0.3 mH/18 ga 0.4 mH/18 ga If you have a way to measure the inductance, you could try measuring some of the good ones to confirm. Or if you post a schematic of the cross over, one of us could probably tell you if that value makes sense.
|
|
#
?
Dec 16, 2012 00:18
|
|
|
SnoPuppy posted:If I had to guess, I'd say that the first number is the value in mH and the second number is the wire gauge. That seems like a reasonable interpretation. I was thinking the 18 might be the gauge actually. I am about to run out to dinner, but I will draw up the schematic and post it later. Thanks!
|
|
#
?
Dec 16, 2012 00:25
|
|
|
armorer posted:The two small inductors might be ok. The large one looks pretty bad from the side though. I would be surprised if the enamel didn't melt. It looks like it all melted together and even ran down the side a bit. Those resistors look fine. They're basically encased in sand or something, so they're survivors. If anything, sand them off slightly so they don't smell like burnt electrolyte when the heat up. If possible, I'd replace all of the caps, if the crossover is old. However, I don't know WTF is going on with those--they have a goddamn J on them, which I sure as poo poo hope isn't for "joules" (although this could technically be possible, as you can determine capacitance from stored energy at a given voltage...but still). As for the inductors, they look like they might be made in-house, or something.The x/18 on the labels might mean something. Does 18 correspond to anything common? Core size, wire gauge, etc...You might need to build your own inductors, using the good ones in the other circuit as a guide. If you get the correct size of enameled wire, and reuse the cores in the damaged inductors, you can rewind your own replacements. Unless you have an LCR meter, then you'll probably have to do something like measure the DC resistance of the good inductors, and use that to determine that your replacement has approximately the same # of windings.
|
|
#
?
Dec 16, 2012 00:27
|
|
|
I just checked and the inductor wire is all 18 gauge, so that might explain the "/18". I thought I would be fine to locate the capacitors, but that J is throwing me off as well. I am running out now though, I will post a schematic later tonight after I have time to draw one up. EDIT: It is entirely possible that I am too drunk to be attempting this right now, so if this circuit doesn't make any sense please yell at me and I will fix it (most likely tomorrow).  The parts I think I need to replace are: L1, L2, L3 (L1 and L3 may be fine, L2 I am highly skeptical of) C1 is definitely toast R1, R2, and R3 I am told are fine (although they are sitting on lots of char). It looks like most of the scorched bits around them are actually the glue that was holding them in place. The resistors themselves may indeed be fine. Also ignore the "AL11P" marking on the speaker symbols, I just grabbed some random crap in Eagle to throw this together. EDIT2: Now that I am awake and sober, I see that I mislabeled L4 and L5. They should be ".17/18" and ".18/18" respectively. Also I am tempted to just pull a few of the capacitors and measure them to see if I get anything that corresponds reasonably to the markings. I may do that later today. armorer fucked around with this message at 15:33 on Dec 16, 2012 |
|
#
?
Dec 16, 2012 00:48
|
|
|
I'm guessing those caps are labelled the same as other film/ceramic, except in microfarads instead of pico. I don't know why, but that would make the most sense. It would put the crossover frequency around 1-1.5kHz.
|
|
#
?
Dec 16, 2012 18:28
|
|
|
My work area is sorely lacking in good lighting. Any particular lamps you guys use when soldering and doing other fine work that you would recommend? I'd prefer some nice bright articulated LED lamp, dimmable if possible. A magnifier might be nice too, but I don't care too much about that.
|
|
#
?
Dec 16, 2012 22:24
|
|
|
I need help with this LCD screen that I took from an Avaya office phone:  It should still work, but I cannot find any information on the internet about the internals of the phone I took it from, much less this specific part. No hope of a datasheet. It's from a phone like this:  General engineering question: How does one go about reverse engineering something like this, or getting it powered up and possibly displaying anything? Should I just run a voltage through the nodes where the cord attaches, and see if anything happens? I want to reverse engineer more, and make use of devices I find with usable parts, but I don't know where/how to start. The only parts I'll be able to salvage are the bright red surface mount LEDs, otherwise I'll just have to throw the screen out. Seems like a waste. Edit: vvvvvvv Nope, I can't pry it up without breaking the screen. I don't see an obvious chip under there after wedging up one edge but that doesn't mean there isn't one. Kire fucked around with this message at 00:13 on Dec 17, 2012 |
|
#
?
Dec 16, 2012 23:55
|
|
|
Kire posted:I need help with this LCD screen that I took from an Avaya office phone:
|
|
#
?
Dec 17, 2012 00:04
|
|
|
Separately: are there any EE blogs as good as Hackaday in terms of frequency of updates, variety, etc? I checked the OP but didn't see a very extensive blog list.
|
|
#
?
Dec 17, 2012 00:15
|
|
|
peepsalot posted:My work area is sorely lacking in good lighting. Any particular lamps you guys use when soldering and doing other fine work that you would recommend? I'd prefer some nice bright articulated LED lamp, dimmable if possible. A magnifier might be nice too, but I don't care too much about that. I bought a $8 IKEA lamp...uhh, the Tertial I think. Works great, articulates in every direction.
|
|
#
?
Dec 17, 2012 00:18
|
|
|
Kire posted:Separately: are there any EE blogs as good as Hackaday in terms of frequency of updates, variety, etc? I checked the OP but didn't see a very extensive blog list. http://dangerousprototypes.com/ has a pretty good blog. I basically follow that and Hack-a-day.
|
|
#
?
Dec 17, 2012 00:58
|
|
|
Kire posted:
If you still have the phone, you can probably identify the power and data pins by powering it up and monitoring the outputs. A logic analyser could be useful to look at the communications between the two. If you don't have the phone any more (or it doesn't work), then it could be a lot of work. Apply power to a ground or use the wrong voltage and you could easily fry it. Even if you figure out the pins you still need to work out what protocol it's using, which would probably be quite a lot of work on its own. If you can't find any data on the screen or its components, and you're not really lucky, it will probably be more effort than it's worth. Good luck!
|
|
#
?
Dec 17, 2012 01:06
|
|
|
Kire posted:
In the past, I have had good luck with the "google every word i see and everything that looks like a part number" method for tracking down datasheets for unknown LCDs. Optrex is an LCD manufacturer that I think got bought out by Kyocera. On Kyocera's site, they have a bunch of parts with numbers that resemble the "F-55023..." that got cut off by that white patch (above the 'MADE IN' [probably China] that got cut off by the same patch). I suggest peeling that patch back and googling further. Failing that, given the connector type and a sprinkling of knowledge of common LCDs, it probably can be controlled by either SPI with some command set or an 8-bit parallel interface (there are some semi-standard ways of doing this as well as some bespoke ones) and it's likely that similar devices from the same manufacturer work similarly; cf. http://www.kyocera-display.com/products/mono.asp and http://www.kyocera-display.com/products/groupdetail.asp?g=Monochrome-Graphic&s=2.8 &cetera.
|
|
#
?
Dec 17, 2012 04:19
|
|
|
Maybe I'm just really bad at searching for things on the internet these days, but does anyone know where I can buy a sizeable pack of prefabbed breadboard jumper cables that are male on one end and female on the other?
|
|
#
?
Dec 18, 2012 06:22
|
|
|
Martytoof posted:Maybe I'm just really bad at searching for things on the internet these days, but does anyone know where I can buy a sizeable pack of prefabbed breadboard jumper cables that are male on one end and female on the other? That kind of thing is easy to find on ebay, the downside is waiting 2-3 weeks for it to arrive from china: http://www.ebay.com/itm/40PCS-Dupon...=item2c6ae65982 There's a few US sellers as well (assuming you're in the US) but you never know for sure about shipping times with ebay sellers: http://www.ebay.com/itm/40-Conducto...=item25707c271f
|
|
#
?
Dec 18, 2012 06:37
|
|
|
Martytoof posted:Maybe I'm just really bad at searching for things on the internet these days, but does anyone know where I can buy a sizeable pack of prefabbed breadboard jumper cables that are male on one end and female on the other? Adafruit and Sparkfun carry them. They also have different sizes/quantities if you need more or less. You can also get M/M or F/F if you need those too.
|
|
#
?
Dec 18, 2012 07:11
|
|
|
Thanks guys. I think I need to refresh my google-fu.
|
|
#
?
Dec 18, 2012 07:14
|
|
|
So, I've been an 'electronics guy' for decades, but admittedly cargo-culted some of it. As time moves on, I'm actually retracing my steps and relearning the fundamentals. This week's project was a wacky gift, and I homebrewed a miniature stoplight out of conduit fittings, LEDs and two 555 timers. I started off with a copied-and-pasted circuit, which didn't work. So, I got mad, and read the Wikipedia page for the 555. Then I read the datasheets. Then I studied the poo poo out of it some more until I understood how it _actually_ works. The next night, I sat down in front of my bench (NOT Multisim) and built a timer from scratch, using my own calculations and schematic. And it worked perfectly! I now 'get' the 555. Mini milestone.
|
|
#
?
Dec 19, 2012 18:57
|
|
|
Martytoof posted:Maybe I'm just really bad at searching for things on the internet these days, but does anyone know where I can buy a sizeable pack of prefabbed breadboard jumper cables that are male on one end and female on the other? Pololu has the best selection I've seen. They also sell lengths of pre-crimped jumper wire in various lengths and colors (and assortments) and empty shells so that you can build your own oddball cables easily/quickly. I bought a bigass assortment of the shells and I use them all the time when I'm prototyping. It's nice for bulding _just the right_ cable for any application (assuming it's 1-to-1 pinned and uses 0.1" breadboard headers). Poopernickel fucked around with this message at 03:36 on Dec 20, 2012 |
|
#
?
Dec 20, 2012 03:26
|
|
|
I'm going to school as an Electronics Engineering Technician at a college here, its a 2 year program. Wondering if anyone here did anything similar could talk to me about what you do for work / how the pay is?
|
|
#
?
Dec 20, 2012 20:12
|
|
|
Phiberoptik posted:I'm going to school as an Electronics Engineering Technician at a college here, its a 2 year program. Wondering if anyone here did anything similar could talk to me about what you do for work / how the pay is? I too am an EET student. One of the college magazine things stated that the "average" starting pay for an EET (2 year graduate) was $56k per year. (based on national averages and job studies by the department of labor (2011 figures)) This assumes a ton of things like you live in an area that actually has that kind of job opening. Realistically in my area I could expect to earn $20 an hour starting wage or equivalent salary (based on industry reps coming to the school looking to recruit soon-to-be college graduates for apprenticeship programs) but it'd be in a maintenance related discipline. I think there are only two companies in a 100 mile radius that actually have EET specific job postings (both government contractors).
|
|
#
?
Dec 21, 2012 04:54
|
|
|
Not salary related, but we love the tech at work. Makes our lives ten times easier, and improves our development time since prototyping is much quicker.
|
|
#
?
Dec 21, 2012 15:10
|
|
|
Kasan posted:I too am an EET student. One of the college magazine things stated that the "average" starting pay for an EET (2 year graduate) was $56k per year. (based on national averages and job studies by the department of labor (2011 figures)) How do you like it so far?
|
|
#
?
Dec 21, 2012 15:33
|
|
|
|
| # ? May 9, 2024 18:51 |
|
|
Phiberoptik posted:How do you like it so far? Its fun. I've fiddled with electronics since I was small child, and its nice after so many years of making magic blue smoke randomly appear to be able to gain practical knowledge to further my hobby. Its beyond and understanding of making things work and delving into why and how things work. Plus is been a pretty handy refresher on trig and physics.
|
|
#
?
Dec 21, 2012 16:42
|
|