Ask MetaFilter questions tagged with electronics

Modular Optical Sensors

nickerbocker — Tue, 14 May 2013 07:28:10 -0800

In my previous question about photo/optical detectors I received a LOT of great advice and I'm back for more. Here is a link to the previous question if you are interested:

http://ask.metafilter.com/212785/Please-help-me-see-the-light

I found out a lot of things that work and things that don't work since then. What I'm struggling with is finding decent optical sensors in packaging that I can mount. I found this company (AutomationDirect) that sells a fairly wide range of modular optical sensors but they all seem to be geared towards "laser trip wire" type setups. I love the packaging and that is what I'm primarily after but I'm interested in getting an output that is proportional to the light level the sensor is seeing.

What I've been using so far are the LTR-301 phototransistors. These are meant to be PCB mounted, but instead I've soldered the through-hole leads to wires and fixed the sensor in place using Teflon (PTFE) mounts between screwes. This is just too problematic from a stability standpoint. I need basically what I've got in better packaging and I don't have the skills (or time) to develop that myself. I'm seeing now that the cost of these optical sensors is mostly in the packaging as the electronics in these are pennies.

For this particular application, I'd like to be sampling the sensor at a rate of 2kS/s - 10kS/s.

Thanks for your advice and any further correspondence that you can provide.

Additionally, I DO have some "laser-trip-wire" projects and am looking for additional resources for those kinds of components (like the ones I linked to from Automation Direct).

Buying electronics on Craigslist

triggerfinger — Thu, 02 May 2013 20:40:22 -0800

Should I buy a TV off of Craigslist? I am looking for a 40-50 inch newer TV. I don't care if it's plasma or LED. But I don't really want to spend more than $500, which puts TVs that size pretty much out of my price range. But there seem to be a ton of them on Craigslist - would it be a bad idea to buy one? If I were to buy one, what would I need to look for/be aware of when buying a TV from someone on Craigslist to minimize my chances of getting scammed? I assume that I would need to plug it in and try before I buy (and of course I would not go alone) and I would make sure they have the owners manual and all the parts that came with it.

What else would I need to look for? I know pretty much nothing about electronics or buying things off Craigslist so any suggestions welcome. Thanks.

Fixing a DDR pad: irritating flex cable edition.

curious nu — Fri, 19 Apr 2013 15:30:23 -0800

It looks thusly. My issue is that, despite the fact that it was originally barely taped down at all, I am unable to successfully, reliably reattach it using the same method. ("it" in this case being the printed black strips on the left). I am reasonably sure that lack-of-contact is my problem, because if I physically hold the cable to the board, it will reliably work when I push a button. Best I can do is that sometimes, after putting it all back together for the Nth time, one button will work. Maybe other buttons on its side will work, maybe not. Maybe it'll work for a few presses and then quit. The cable looks fine, the board contacts look fine, no amount of scotch tape is helping me out here. How do I affix these suckers but good?

Adaptor / converter plug US to NZ

Frisbee Girl — Sun, 14 Apr 2013 17:39:25 -0800

In a few days, I leave on a trip to New Zealand. New Zealand, apparently not being the most popular destination from SF or the US, in my online and storeside research, I have received no less than 6, often contradictory, combinations of answers to exactly what peripherals I need to have in order to charge my phone [though that most often will be trickle charging off of the laptop], run my laptop, and use my hair styling instruments [should I deem to do so.] I do not need to use them all simultaneously, but two at a time would be ideal, if not requisite at times. Can anyone explain to me exactly items I need to purchase and what that setup should look like in order to avoid frying my electronics? Thanks! FG

Help me understand the electronics in my doorbell

whir — Thu, 04 Apr 2013 18:38:08 -0800

I'd like to hook up a small raspberry pi project to my apartment's doorbell. I've taken the case off to take a look at the wiring and it looks pretty simple, but I have some questions about it; apart from some breadboard experiments I'm an complete newbie to electronics. The doorbell is shared with everyone else in the building; it's got a button to listen to the person speaking down below, a button to speak to them, and a button to buzz them into the building. What I want to do is attach the pi to the circuit such that it will detect when the doorbell rings and notify me over IM, and then optionally buzz the person in (the practical reason for this is that I have a long narrow apartment and can't hear the buzzer from the bedroom). I'm fine with the software part of this project, getting the network stuff working, etc. What I need help with is the hardware part.

Here is a picture of the inside of the doorbell case - I've labeled the leads corresponding to the door, listen, and talk buttons respectively.

What I'm curious about is this:

* It looks like each of the leads has a twisted pair of wires coming to it. What's with that? I would expect one wire per lead, and it certainly looks like each pair is electrically connected anyways.

* Are the wire colors in some sort of standardized scheme that I can look up or something? (It's not clear from the picture, but all four pairs are bundled up in a larger cable.)

* It looks from the circuit like the wire marked "X" is most likely the ground, right?

* The number on the upper right-side of the circuit board is "2/96", does that mean anything sgnificant?

* Is there a standard or common voltage for these types of doorbell systems? (I do plan on measuring it with a multimeter to before I attach anything else to it, and I'm cognizant that it could have dangerous levels of current.) Am I likely to be able to attach one of these leads to a GPIO pin directly (assuming a resistor of the right type) or would I need some more complex electronics in between?

* Any other advice about this project?

One thing that is vexing me right now if the power setup - I can probably fit some kind of batteries or something in the case along with the pi, but ideally I'd like it to just be powered through the lines in the doorbell itself, or maybe be asleep most of the time and then when the doorbell rings, awaken, connect to the wifi and send me a message.

What's the easy way to get 12V power and ground to test some car parts?

iknowizbirfmark — Wed, 03 Apr 2013 08:10:42 -0800

I've got some car parts I'm selling on eBay, and I need to hook them up to power in order to check a few things and make sure that they work. The items I need to test are mostly gauges and electronics and won't take much power at all. I don't want to mess around with my vehicle's wiring to hook these up. What is the easiest and cheapest way to get 12V power and ground like I would from a car? Is there an easy way to connect the right wires to a cigarette lighter adapter in a car, or can I get something that I can plug in to AC to convert to DC power with the right wiring?

Looking for cool electronics building kits

Admiral Haddock — Thu, 21 Mar 2013 10:43:51 -0800

I've been building guitar pedal kits from buildyourownclone, and it's been great fun. I'm running out of pedals I want to make for myself, and am looking for other projects, like this stereo tube amp, and maybe this sous vide. Can you recommend more electronics projects (preferably kits, so I don't have to scrounge for parts) that are cool and look good at the end? I'm not particularly computer minded, so I'm not really looking for arduino-based kits--I'm not really looking to program anything. I like soldering.

Evilmadscientist has some cool looking kits.

Any others? Has anyone out there built a stereo tube amp? Is there another kit you'd recommend? How about a sous vide kit, or alternate project I should look at?

In addition to having all the bits and bobs, I prefer kits because I don't have a real workspace, so I'm not in a position to hack a lot together--and I do want something that looks good when I'm done.

So, for instance, this alternative tube amp kit, shown mounted on a piece of wood, is less appealing than paying (significantly!) more for the other kit which comes with a nice looking enclosure.

(I also definitely don't want to electrocute myself or burn the house down, so well documented kits from reputable sellers are highly preferred!)

Suggest Electronica Suggestive of Electronics

dephlogisticated — Mon, 18 Mar 2013 20:40:43 -0800

I like songs that evoke images of circuitry, complexity, and digital processes. What are some songs and artists that convey this feeling? Examples:
Remind Me (Someone Else's Remix) by Röyksopp
Default by Atoms For Peace
In Motion from the soundtrack for The Social Network

What are some other songs of this type? Preferably uptempo. Bonus points if the tone is vaguely sinister.

Digital Electronics: Keeping a logic level high or low for one minute

mbarryf — Fri, 15 Mar 2013 06:13:33 -0800

I want to use a timer (minimum on time is one minute) to turn on my coffee maker. The ON-OFF button on the coffee machine is a momentary contact push button which is read by a logic board. Can I use the (isolated) relay contacts on my timer to close that push button for one minute, the minimum on-time of my timer? The coffee maker is a Starbucks (Saeco) Sirena, and I need it to pre-heat its little boiler for about 20 minutes before I make coffee. I have a timer (clock) that I have modified to close a pair of relay contacts at the set time. (These contacts are isolated from the 110 VAC line.) The minimum on time for the relay contacts is one minute. (I prefer not to build a 555 timer circuit as a one-shot for a shorter duration). I am quite sure that the power button on the Sirena simply sends a logic high or low to the circuit board (I have the wiring diagram). I have tried holding the power button pressed for over a minute, and the Sirena simply went on, as if I had done a momentary press and hung around for the remainder of the minute.

I want to use the relay contacts (wired across the power pushbutton -- which is a logic controller, not a power controller) to simulate a press. It will either force the logic level to high or ground (depending upon how the Sirena is currently wired).

I think that it is OK to hold that logic level for the minute. What do you think?

best sound system for hearing movie dialogue

Afroblanco — Mon, 11 Mar 2013 13:17:00 -0800

Ever since the DVD age began, I've noticed that music and sound effects in movies are always WAY louder than the dialogue. It's really annoying. Will a properly configured surround sound system fix this? What is the right way to set up surround sound speakers? Are sound bars any good? I've never gone through the trouble to properly set up my surround sound speakers. Whenever I've had surround sound systems in the past, I've put all the speakers next to each other, beneath my TV set. However, when watching movies, it's always annoyed me how much louder the music and sound effects were than the dialogue. I figured this was happening because I didn't set up my speakers properly. A few years ago, I switched to this sound bar. However, I've noticed the same problem : loud music and sound effects, soft dialogue.

Will a properly configured surround sound system fix this problem? If so, what's the right way to set up the speakers? All the diagrams I've seen put the rear speakers in back of the viewers. This is impractical for me : my sofa sits flush against the back wall of my living room. So if I mounted the rear speakers on the wall, they'd be roughly on top of the viewers' heads. In order to put the rear speakers behind the viewers, I'd have to move the sofa out from the wall somehow and keep it there. Not ideal. Doesn't everyone else have this problem? I don't think I've ever been in a living room where the sofa was in the middle of the floor.

Alternatively, will a decent sound bar solve this problem? I'm not happy with mine, mostly because of this music/effects vs. dialogue problem. Also, the volume doesn't go up high enough.

Finally, if neither a properly configured surround sound system nor a sound bar will make movie dialogue more audible, what will? I'm really sick of turning up the volume so I can hear dialogue, and then having to keep my hand on the remote so I can turn the volume down once the music/effects start. Doesn't anybody else have neighbors?

What's the best e-reader for me?

Scientist — Thu, 07 Mar 2013 09:39:58 -0800

I know pretty much nothing about the e-reader market right now, but I'm thinking about taking the plunge. Given my particular requirements, what is likely to be the best e-reader for me? So I've realized that lately I've been doing a lot more onscreen reading than on-paper reading -- mostly on my laptop and my phone. I'm OK with this but neither of them are perfect, and I've been thinking that since this situation seems unlikely to change in the future, it might be time to spring for a dedicated e-reader. Problem is, I don't really know what the landscape looks like for e-readers right now. I do, however, have a good idea of what I am looking for in such a device.

The three main file formats that I read are PDF, ePUB, and TXT in that order, followed by DOC/DOCX. This does not look like it is going to change for me, so I really would like an e-reader that has native support for at least the first three of those formats. I do not buy ebooks from any online markets nor do I have any interest in doing so, but I constantly have to read scientific articles which are typically provided in PDF format, and spend almost as much time reading freely-available fiction which may be presented as a PDF or TXT file but which I prefer to get as ePUB when possible. I also frequently have to read notes, memos, and other emphemeral documents which generally come to me as TXT or DOC/DOCX files. It would be nice to have basic HTML rendering capacity as well but the only truly required formats are PDF, ePUB, and TXT. I could get by with just PDF and ePUB if forced to I suppose, but good native support for at least those two formats is an absolute requirement. Yes, this rules out the Kindle. PDF support should include highlighting and annotation capability.

The other biggest requirement for me is a good screen. The whole point of an e-reader is that you are going to stare at it for long periods of time like you would a book, so I feel like having the best possible screen is kind of a key selling point. I know that I definitely want an e-paper display, that's mandatory. High resolution and high contrast, as well as an excellent backlight, seem like they would be the most important factors here. Also, it would be nice if it were bigger than the 6" size that seems to be standard these days (the PDFs I read are usually two-column documents and rarely reflow well) but that's not a dealbreaker. I think I would prefer a touchscreen interface.

It should also, of course, have reasonable build quality and a thoughtful, responsive UI -- I don't want to spend hours a day gripping something that feels like a piece of trash and is frustrating to actually operate.

I need to be able to keep my documents synced across the various devices that I use: primarily a laptop, phone, and this hypothetical e-reader. Currently I use DropBox for this, but would be willing to deal with another solution as long as it is similarly seamless. I do not require 3G support, WiFi is good enough for me as long as it is easy (ideally automatic) to keep my personal library synced across my computer, phone, and e-reader. I would like to have the option of browsing my library in the filesystem rather than in some custom library app if possible (at least on my laptop, anyway) because I am a cranky old man in that way. I would vastly prefer local storage in addition to or instead of cloud-based storage, rather than cloud-based storage alone, as I need to be able to access documents while offline.

Price is not really the main object, though obviously I do care about value for money. If there is not currently an e-reader that fulfills all of my desires, I am willing to wait -- especially if there is something in the pipeline that seems like it would work better for my needs.

Oh, and whatever it is it has to be readily available in the U.S. as that is where I live. Thanks very much for your recommendations, I really appreciate it!

Securing Various Electronics in the South Pacific

DaftMythic — Thu, 28 Feb 2013 21:59:49 -0800

What would be the best ways to secure multiple laptops, smartphones, cameras (physically, and also to catch thieves) in a "rustic" foreign country... keeping in mind I need to fit everything in luggage or fashion it out of raw materials in country. Thoughts:

Secure Laptops - Laptop locks (for short term). Safe? Strong Metal Bag? Something else? (long term)
Secure Smart Phones & Cameras- Safe?
Secure premises - Small mobile hidden camera system??

Only Security systems that work in southern hemisphere/remote. GPS or online monitoring is great but worthless if I cannot use it there.

Rather stay away from monthly fees. Budget is not extravagant, but rather bring key pieces with me since local markets are not that helpful.

---Background---

I will be moving to Fiji for the next 4 months, possibly longer. I may be in an apartment but I'm not sure that will offer much security. I've visited the places I will be staying and have already had things stolen from me multiple times in nice hotels.

Add to that I may be holding on to a wide variety of electronics (laptop, smart phone, camera, etc). Most will be my own and my fiancee's, but I also expect to acquire some items for friends so might have multiples.

So.... security is a consideration. I know laptop locks are merely for opportunistic theft, but I'll probably bring a few of those anyway.

My main thought was a rather large safe that I might be able to fit in my luggage and then chain/padlock to a wall, but I am concerned about the weight. I don't trust I can find anything appropriate in country. Plus I may move a few times while there so don't want a safe that is utterly immobile.

As I am thinking about laptops especially it seems like for a secure long term option (like if you leave the house for a day without it) you could weld metal plates into a cross formation with loops on the end and then run chain/cable through each end and padlock them on top (like a bow and ribbon on a gift box). Surely someone has thought of this and there are pre-formed ones?

I was thinking if I could get the basic parts (plus a light but sturdy safe) I could acquire the chain/steel wire and padlocks there to cut down on weight.

I would like to get some cheap GPS beacons and hide it in all my stuff, but I don't know how feasible that is, and how much the service to locate stuff would be.

Finally, Some sort of 24 hour security cameras... Of course they would have to be inconspicuous enough so that people would not just disable them (or steal them). I've never done anything like that, so not sure what best options are.

Of course I am open to any other consideration or advice. Thanks in advance!

Cell phone repair trouble

delezzo — Wed, 27 Feb 2013 22:29:41 -0800

I'm trying to fix my phone. How do I deal with a very tiny, hard to get at screw with a stripped head? I'm trying to replace the glass touch screen on an LG Shine Touch using these instructions. The heads on two of the screws - one under and one beside the battery - are stripped and I can't get a purchase on them at all. I'm using the magnetic screwdriver I got with the new screen.

I have absolutely no experience with this. I've tried small amounts of sticky tack and rubber cement, but it didn't help. Should buy a slightly larger screw driver? Resort to superglue? Let me know your tips and tricks!

Thanks!

Warranty providers show earlier purchase dates for Amazon electronics?

ziggly — Wed, 27 Feb 2013 14:48:36 -0800

I've had this problem twice now: I purchase an electronic item from Amazon and when I call in for service under warranty, I'm told that their records show a different, much earlier purchase date. This happened with a major repair for a trivial machine (tiny Cuisinart food processor) and a minor repair for a major machine (Macbook Air.) In the case of the food processor, they told me I was actually out of warranty because they showed a purchase date that was at least several months before the date I actually bought the thing. I wound up forwarding an email receipt from Amazon and that seemingly worked out.

In the other case I bought a 2011 Macbook air new on Amazon last year in October 2012. The battery life showed 96% on its first run out of the box, which was strange because it also showed 0 charging cycles, but I assumed that just meant it had been lying in a box since 2011 or so and had deteriorated a bit. (I ran the CoconutID program and it says the computer was actually built in April 2012.) Then I took it in to an Apple store recently for a minor repair, and they took care of it, but the email receipt from Apple I says that the purchase date for this serial number is June 1 2012! I am going to call Apple shortly to ask what I can do about updating the warranty. Mostly I am alarmed that this has been a pattern and if the items I think I'm buying new are actually refurbished or slightly used returns. Amazon already has a pretty robust open box sale section, so I'm surprised if that would be the case.

I did try emailing Amazon's customer service after the food processor incident and got no reply. Now I am just befuddled. I am wondering if anyone has any explanation or would know about any tipoffs in the product listings (again, both items were billed as new and sold by Amazon, not some shady-sounding third-party retailer).

Need help restoring bricked Verizon Galaxy Nexus

mattholomew — Sun, 24 Feb 2013 06:14:00 -0800

My rooted verizon galaxy nexus won't boot and I need help recovering it (more inside) I have a Verizon Samsung Galaxy Nexus that is rooted and was running Cyanogenmod 10. I was trying to wipe data to prepare for selling it and I messed something up. Details:

It goes to the Google screen with the unlock logo but won't go past that, even after letting it sit for an hour.

Tried booting in to recovery, wiping cache and wiping dalvik cache to no avail.

Pulled battery and tried to boot to no avail

I do not have a backup to restore to

Tried installing Wugsfresh toolkit on my PC but the phone won't connect as a USB device

me want magic screen box

FirstMateKate — Fri, 22 Feb 2013 12:28:57 -0800

I would like to purchase an off-brand tablet computer from a discount electronics website. I know nothing about components or specs or anything- the only info I have to go on is bigger number is good. Please help me. (sorry but this post got way too long, you've been warned.) Hello people who have decided to help! (and those of you who also might need help)

I want to purchase a tablet, but I don't want to pay for a name brand product. I've heard good things about dx.com from you mefites, since they have pretty reliable product reviews. The shipping time is quite long, though, and I've found that Light in the Box and Focal Price seem to be the same thing, but with better processing times.

Here's what I want it for:
•ereading (all of my textbooks are ebooks and dragging my laptop into the lecture hall is dumb because it's bigger than the fake tiny desk we're given.)
•reading metafilter (srsly is what I do most of the time on the internet.)
•showing digital portfolio pieces. (these will mostly PDFs that I'd be showing people. So much easier than getting prints of my work, but I do want to make sure the picture quality is good so it doesn't make my work look crappy.)
•watching netflix/ TV on network sites.
•tumblr (don't judge me)
•I know there are sketching apps out there. This could be fun.

Here's some tablets that have (a lot of) great reviews and seem to be what I'm looking for. Can you help me pick the best one/find a better one in the same price range (>$175)

•#1 is 8g and 1.66hz (thats a good number, right?) It supports flash, apparently. And it's a multi-point capacative screen. ( I read that capacative screens are better. Please tell me if I'm wrong.) It also says this :"Support Extend Card 32GB". I do not know what this means. Does it have SD storage? It also has a built in microphone. So, like, I can skype I guess? It also has a dualcore processor. I assuming this is better than a single core processor.

•#2 is ver similar, but it does not support flash. It does support SUB 3G, but my smartphone has (remarkably good) wifi hotspot, so I don't think I need this feature.

•#3 specifically states that it has access to android market. I know that this has been an issue with off brand, non google supported devices.

Those are I think the best options, I'm only going for items that have more than 50 reviews, for safety reasons.

If you see another tablet that is better, please, by all means, let me know.

I do have some other questions

With it being a non-supported device, what kind of trouble will I run into? Updates? Security? Lack of access to apps? Not being able to watch TV on like cbs.com? How do I bypass these problems? If I root it, how? I am not tech savvy, but I'm a smart lady, so if theres a good, simple, step-by-step guide I can do it. Or, alternatively, I purchased a used smartphone from a local electronics store that was rooted, and they seem to be hardcore software guys, and could do it easily. I'm sure if I paid them they would. If rooting is vital, would you suggest I get it done by a "professional"?

Looking for the perfect iPad 4 case

JoanArkham — Thu, 21 Feb 2013 08:20:46 -0800

I just bought an iPad 4, and (since I rarely spend this much on myself) I'm really paranoid about taking care of it. All the special snowflake details inside... The main things I'm planning on using it for are surfing the web while on the couch and watching movies and TV while on the treadmill. I have a shelf set up in front of the treadmill, so I don't need to rest the iPad directly on it, but it does get a little wobbly if I'm jogging hard.

I'll probably wind up traveling with it at some point, but I won't be carrying it back-and-forth to work or anything.

I was originally looking for something with a fun design, but now I'll settle for just functional.

Based on this previous question I was looking at BookBooks and Dodo cases (they're both beautiful!), but I'm concerned they won't function as a sturdy stand for movie viewing.

I also found this one via that thread, but I'm still concerned about sturdiness. Also, we bought a similar case for my mom's iPad at Christmas, and it took several tries to get the thing to fit. And I am known for breaking things with my freakishly large man-hands. (Doorknobs, handles, important little plastic bits, etc.)

The best the Apple store could do was a $40 tripod thingie to go with the $50 SmartCase.

Any help, especially first-hand experiences, would be appreciated!

What soldering iron should I buy?

Merzbau — Sun, 17 Feb 2013 18:27:11 -0800

I'm starting to mess around with electronics as a hobby and need to buy a soldering iron. But which one? Bonus question: a cheap, effective multimeter? I know basically nothing about electronics or engineering (the book I'm using as a guide, Nicolas Collins' Handmade Electronic Music: The Art of Hardware Hacking is targeted toward music and art students, which suits me fine). Collins recommends a soldering iron in the 25-60W range, and recommends the Weller brand, but offers little guidance beyond that, and there are quite a lot of choices on Amazon and other sites. I'm looking for a cheap, reliable entry-level iron with replaceable tips suitable for working on small electronic components. I also need to pick up a multimeter fairly soon, but again, I'm not really sure what features are necessary or what manufacturers make a quality product. Any recommendations?

And one last question: how well-ventilated does my workspace need to be when working with solder? Would it be all right to set up next to an open window with a fan, or should I put together something more elaborate to make sure I stay safe?

Do I need to replace the whole radio in my car?

sunshine arakhan — Thu, 31 Jan 2013 16:24:13 -0800

I have a 1995 Toyota Corolla Conquest who's factory standard radio has just died (I think). It made a slight noise last night and cut out, and is now just flashing 01:00 on the clock with no buttons responding at all. I thought maybe the fuse had blown so I checked the radio fuse, but it doesn't look to have blown (something I suspected as a time keeps flashing on the display and I thought a blown fuse wouldn't allow any electronics to work). Also the cigarette lighter still works and that is connected/part of the radio fuse. To avoid me taking it somewhere and being charged to be told "you need a whole new radio" - does it sound like I need a new radio? Buying and installing one isn't a big issue, I just want to be somewhat sure that's what I need to be doing.

How to get a plastic case made for a prototype product.

Charlie Lesoine — Fri, 18 Jan 2013 15:24:53 -0800

I am making a prototype of a consumer electronic device, the final product will be housed in plastic. I want to get a case made for the prototype that will resemble the final product. The case design is nothing complicated, essentially a rectangular box with some rounded corners and some holes for buttons, etc. I have designed the look of the outside of the case in adobe illustrator (top, bottom, front, rear and side views). The case will have a top shell and a bottom shell that fit together. What is the best way to go about getting maybe 2 cases made for prototypes? I am thinking either cnc or 3d printing, but I don't know what the best route to making a 3d model is from adobe illustrator or anything...

Please help me fix my iPod!

reductiondesign — Thu, 17 Jan 2013 17:52:48 -0800

My wonderful iPod, going on nine years now, seems to have finally gotten to the point where I can't fix it anymore. I've replaced the hard drive, battery, hard drive cable, and logic board, and yet all it does is turn on, show the Apple logo, and turn off, repeating over and over. What else could be wrong, and how can I fix it? This is a B&W 4th gen iPod, originally 40 GB.

Why are my headphones not playing vocals?

cyml — Thu, 27 Dec 2012 18:55:00 -0800

I have a pair of Monster Inspiration. I'm trying to play Madness by Muse but if I plug the headphones completely into the iPod or computer, I can't hear the vocal parts at all. If the jack isn't completely in, then I can hear it perfectly. Why is this happening?? The back-up vocal parts remain intact - it's just the main parts. This is the only song that does this. I tried different equalizer settings but nothing works. Is this just a quirk of the headphones or is this not normal?

I tried it with other songs and I've noticed that if I plug in the entire jack, it gets duller sounding. The bass doesn't get any louder... the entire volume just comes down and it sounds less punchy.

I just got them so I don't think I broke anything yet. I've had other high-end headphones and this is the first pair I've had something like this happen on. Should I return it?

Need a hobbyist electronics shop in Toronto

PercussivePaul — Sun, 23 Dec 2012 13:23:25 -0800

Where in Toronto can I buy small cylindrical rechargeable 3.7V Li-ion batteries like the UltraFire, hopefully at a reasonable price? (or maybe they were 3.6V, I can't recall) I made a little electronic thing for a Christmas present, bought the batteries at a hobbyist shop in Vancouver where I live (the kind of place that sells Arduinos and such), currently home with the present in Toronto and I'm pretty sure one of the batteries is bad. Sometime in the next week while I'm in town I want to buy a new set of batteries. No time to have it shipped so I have to buy local. I'm based near Bloor/Ossington at the moment but can travel. Thanks.

More than one color to resistor number, what to do?

tmcw — Sun, 23 Dec 2012 12:40:59 -0800

Resistor color coding (the electronic color coding) has more than one color combination to resistor value. How do you know which one to use? I'm a lackluster soldering noob who's trying to get used to basic electronics, and thus have started to rewrite this calculator as a learning exercise.

This ran into the issue that you can have a resistor of (brown, black, brown) which has the same value, 100 ohms, as a resistor of (black, brown, red).

What's the rule for determining a 'canonical' color code - should you maximize the exponent? Or minimize it? I'm finding it hard to find the answer from Wikipedia and such. Thanks!

How to watch Yogaglo on my TV?

Anonymousness — Sat, 22 Dec 2012 07:23:52 -0800

I want to watch videos from a yoga website (Yogaglo) on my TV. The tools I have available to me are: MacBook, xbox 360, and Apple TV. Can I make it happen? As far as I can tell, the videos are not downloadable. They seem to be viewable only on their website. And I'd be happy to buy cables if necessary. The TV is a nice Panasonic plasma. Oh, and the TV is hooked up to an Onkyo TX-NR414 receiver. Thanks!