Ask MetaFilter questions tagged with electronics

Getting the most out of CES?

griffey — Mon, 14 Dec 2009 08:34:53 -0800

What should I know/do as a first time Consumer Electronics Show (CES) attendee? This year will be my first attending CES in Las Vegas. I am attending as Press, and will be covering the event for a library publication that I'm not privy to divulge quite yet...so my focus will be on ebooks, mp3 players, cameras, and other things that libraries might need to care about in the next 12 months. I'll be avoiding the automotive area. :-)

For those that have been several times, any tips? The size of this thing is a bit overwhelming. I'm familiar with Vegas, and am staying in a hotel on the monorail line to get back and forth to the convention center, so I feel pretty well covered there.

Tips for getting the most out of the show itself? Secrets for getting access to things? How do you get the best schwag? I'm really looking for anything "best of" for this beast.

Thanks!

Silicone "skins" for electronics: What happened to the market?

wogbat — Sat, 05 Dec 2009 19:11:21 -0800

Silicone "skins" for electronics: What happened to the market? Used to be you could get a silicone "skin" for just about any electronic device in any color on eBay or a number of sites. I just bought a couple new cameras and can't find skins for them. I also did a search for other new gadgets and couldn't find any. I had skins for my Archos player, an earlier lumix camera, and a few other things. What happened to this market?

(I'm looking for something for the Panasonic Lumix DMC-LX3 and DMC-ZR1)

Suggest some online stores for DIY electronic gadget making.

Charlie Lesoine — Thu, 03 Dec 2009 19:57:51 -0800

Can you recommend some good stores like http://www.goldmine-elec.com/ and http://www.sparkfun.com/ I'm looking for little motors, gears, metal rods, rubber rollers/grommets as well as electrical components.

How to teach myself audio electronics

Charlie Lesoine — Tue, 24 Nov 2009 15:19:16 -0800

I'd like to teach myself electronics with a focus on audio. I'm starting with this book. What should I do/read from there? I have also ordered some prototyping supplies which are in the mail. I know how to solder. I have built one guitar pedal from a kit, which was a breeze, and I've soldered together some microphone cables, but that is the extent of my electronics experience. My short term goal is to build a real analog tape delay. I'd really like to understand all the components and how they work together in order to get a big picture understanding of these things. I want schematics to make sense to me.

eBay for discrete electronic components?

spiderskull — Tue, 24 Nov 2009 14:11:09 -0800

I have several boxes of expensive electronic components (like this DC-DC converter, various high-freq op amps, 14-bit ADCs, several rad-hard milspec discrete devices, etc.), and I'd like to sell them online. Is there an eBay-like Mouser or Digikey-type site?

Printer for fashion company

ChloeMills — Tue, 24 Nov 2009 10:35:20 -0800

Need help figuring out best option for a printer for a fashion company. We currently use the basic Epson Large Format printers that cost between $300 - $500. However we keep having to replace them every year or so. I guess they have sponges that fill up and then you need get them professionally replaced.

I know at past companies we had one with replaceable sponges. However those seem to cost a lot more. How long are those meant to last. Does anyone have good suggestions for ones to use.

I'd say on average we print 30 pages a day, but during busy times it could be more than 100.

I don't know if laser, inkjet or dye printer is best.
We mostly printer on Matte Photo paper, plain copy paper and occasionally card stock. We rarely if ever print on Glossy photo paper.

Important factors for us:
-Longevity. It needs to last long a long time. It's a long and frustrating process when we have to buy new printers because we have to rematch all our color standards which takes a long time.
-Wide range of color. It's important that we can get a pretty wide range of color to match our fabric color standards.
-Color consistency is very important for the same reasons
-Cost - in the past we spent $400 on printers - so I have to show that a more expensive printer will be cost efficient.
-Switching paper - ease. We are constantly switching the size and type of paper we use. So that has to be fairly easy.

Any pointers, suggestions are greatly appreciated. I really don't know what our best option would be!

Is it worth putting time or money into this CD player?

lakeroon — Sun, 22 Nov 2009 17:59:51 -0800

Cheap CD player hisses. Worth the trouble to diagnose or fix? I have a stereo that I received as a thankyou gift for making a charitable donation. It is Insignia brand, which I guess is the house brand at Best Buy. When I play a CD, there's enough of a hiss to make it unpleasant to listen to.

Is there an easy fix for this, or should I just chalk it up to "you get what you pay for" and see if Goodwill wants it?

I need help understanding FETs.

backseatpilot — Tue, 17 Nov 2009 06:18:27 -0800

I need some electronics help - why is this FET not doing what I expect it to? (Please use small words as this mechanical engineer does not often understand the world of electrons.)

I have a circuit that's driving me up a wall! In an effort to build a weather observation station, I have a capacitative humidity sensor that is built into an op-amp integrator circuit. Something similar to this (pdf, see figure 3). I'm using an Arduino to control everything, basically following the same functional block diagram as is in the document - power HI, find the time at V1, time at V2, do some math and figure out the capacitance which is then converted to relative humidity. Then flip the power to LOW and do the same thing in reverse.

The problem, as is common with integrator circuits like this, is that the sensor/cap needs to be discharged occasionally. Based on some other suggestions I found on the internet, I added a JFET in parallel with the sensor and modified my code so that the JFET would close after every hi/low cycle, shorting the sensor and removing the built-up charge.

Unfortunately, it seems that it's in a constant state of short-circuit. If the JFET is in place (and I'm sure that I have the pins where they should be), the integrator circuit does not work. The sensor simply does not build a potential across its terminals, and I'm at a loss why the JFET won't stay in an "open" state.

Is a JFET not the right tool for the job here? Is there some quality of FETs that I'm not understanding? I've done all the most obvious troubleshooting and I'm still at a loss.

Looking for Oscilloscope Recommendations

DMan — Sun, 15 Nov 2009 11:26:12 -0800

I'm a hobbyist looking to buy an oscilloscope, and I need some advice. So, I consider myself to be an electronic hobbyist, and I've decided to take the plunge and get an oscilloscope, having used one in a lab class at school. The problem is, my budget is limited to $200-300.

I see a lot of analog scopes on eBay, like this HP model. Should I be looking for something like this? I know it's important to find a seller that guarantees the item to be working, but will an analog scope work for general hobby electronics?

The one thing I don't like about the analog scopes is the screen. So I found this Rigol one. It's a bit out of my price range, but considering that it's physically a lot smaller than a typical analog scope and has a digital screen, I could justify the added cost. But I've never heard of Rigol and I don't know if they're trustworthy.

So I guess what I'm looking for is an opinion on Rigol if anyone has used one of their scopes, and if that's not my best option, please feel free to recommend a particular brand, model, or a place I can find one for a good price. I realize that I'm not going to get a top of the line oscilloscope for $300, but if eBay is any indication, it seems like I can get something that will work for messing around with parts at home.

Thanks, AskMe!

There's an app for that

popcassady — Sat, 14 Nov 2009 08:50:00 -0800

How can I trigger a relay using my (non jailbroken) iPod touch? I had been using an old laptop to trigger a relay via the parallel port. Sadly, said laptop is very dead now.

Now, I have an iPod touch that I would like to use in its place. I have a developer account and figure that it would be easy to trip the relay via the headphone jack. The controlling app would play a piece of audio whenever the relay needed to be tripped.

Problem is, whilst I'd have no problem with the software, I have no idea where to start with the electronics. What kind of device am I trying to make? Would it be simple or complicated? Is there a name for it? Could you point me to a schematic?

What are some good iPod speakers?

MaryDellamorte — Tue, 03 Nov 2009 15:55:11 -0800

Looking to buy some speakers for my iPod which I have absolutely no experience with. Looking for something in the $150 - $200ish range. Specifics:

-Don't really care about how it looks.
-Don't want it too big or too small.
-I'm shooting for no more than $200, but if there are some phenomenal speakers for more than that, I can go higher.
-I've seen some with sub woofers, how much of a difference do those make?

Looking for the perfect laptop for traveling

Afroblanco — Thu, 29 Oct 2009 08:31:20 -0800

Looking for the perfect laptop for traveling. Priorities are durability, lightness, and battery life, in that order. Performance is not too important, but it must run Windows 7 like a champ. Willing to consider netbooks. Can spend up to $2000, but obviously I would like to spend no more than I absolutely have to.

Greengineering

thekiltedwonder — Wed, 28 Oct 2009 18:45:14 -0800

Save Our Planet Filter: My girlfriend is doing a "green energy" engineering project and needs inspiration. This is a project for an electrical engineering class in college so give us your coolest ideas for green energy projects. The project is supposed to interact with the public - something that could be put on display in an exhibition, a museum, college campus, or anywhere public. Additionally, it must educate the public to "think green" and raise people's awareness of green energy sources.

The description is pretty vague and can be pretty much interpreted in any way she wants, except it MUST provide some sort of user input and some sort of feedback to help the user understand something about green energy sources (solar, hydroelectric generators, wind turbines, or any other means of electrical generation or efficiency.

An example that was given was to have a solar panel on display, and have people put their hands over the solar panel to see how the energy generation of the panel changes with shadow in the way, using a little display. The professor likes this idea because it is educational and it gives back feedback.

Another example that was given to her to inspire her was a public trash compactor that uses a solar panel as its energy supply. Obviously this is a much bigger project and needs some sort of twist to be "educational", but it's another way the assignment can be interpreted.

She's got about a 50 dollar budget for electronic parts and about 7 weeks to complete this, so it's not a huge project, but still worthy of an electrical engineering major. She feels most comfortable working with (small!) solar panels, but is interested in all areas of "green electricity".

So, if you could ask someone to design an interactive electronics project that is green and educational, what would you ask them to create?

Should I buy a Tonium Pacemaker?

jonnyploy — Mon, 26 Oct 2009 08:54:53 -0800

Should I buy a Pacemaker if I am not a DJ and don't have all that much dance music? I am thinking of acquiring the above product which is a pocket-sized DJ system, however I'm worried that my music collection is unsuited. I do have a limited collection of funky house from the last few years but this is mainly in the form of Hed Kandi compilations. I have music spanning several genres including: soul (60s and 70s), funk (60s, 70s, 80s), britpop, 80s cheese, electro-pop from the last few years, it goes on...

Will I be able to effectively mix tunes from these different genres and therefore get good value for money from my purchase?

A secondary, related question: where online can I purchase vocal-only and instrumental versions of songs? I have tried itunes (obviously) and hit a blank. Are these even available to buy?

Math Symbol Mystery

mazniak — Sun, 25 Oct 2009 20:19:54 -0800

I've never seen this mathematical symbol used this way before. Can anyone tell me what it means? Ok, my ignorance is on display for the world to see…

Please look at this image .

I'm referring to the parallel bars between the two resistances at the top. Obviously anyone who's taken 9th grade geometry knows that it is a symbol for describing a relationship as being parallel. But how does it fit here? How is it used to derive the final value of the voltage gain (3.82)?

Modern TV Needed

shew — Sun, 25 Oct 2009 18:03:56 -0800

Help me find a new LCD television for my modern guest bedroom. I currently have the Samsung LN-S3252D in my master bedroom. It's white. It's sexy. I love it. I need another one (or similar) for my guest bedroom. Since that TV is about four years old, I was hoping to get an upgraded model. Has Samsung discontinued this model? I can't find the LN-S* series anywhere. I was hoping that Samsung would have a new version of the same design out by now but no luck.

I'm willing to buy a different TV but do not want to compromise on the design. Has anyone stumbled upon any great looking, modern flat 32" panels out there?

Looking for a camcorder with composite input

jstech — Sat, 24 Oct 2009 22:18:19 -0800

Do you know of any camcorders or portable video recorders with composite (analog) input? I recently received an old helmet camera from a family member, and it needs a separate recording device. So I'm looking for something portable to record from composite input. These inputs are usually TRRS connectors (like a headphone jack, but with four conductors: Wikipedia: TRRS), or the classic yellow-red-white RCA connectors. I'm looking in the $400 range, but I'm flexible.

Who owns the button patent?

shmegegge — Tue, 20 Oct 2009 13:08:50 -0800

Does anyone own a patent for the button? As in, the button you press to turn on your tv, or to dial your phone, or to nuke the planet from orbit. not the button on your shirt. I was once told that someone or some company owns the patent for the standard electric/electronic button, and that any company which uses one must pay a licensing fee to said company. is this true? if so, who? how much does one pay for this?

Electronics! NYC! Quickly!

provolot — Wed, 14 Oct 2009 23:52:28 -0800

Where can I find a cheap network cable tester, tomorrow morning, in NYC? I just realized that I need a RJ45/Ethernet cable tester for something short tomorrow. Is there anything anywhere in Brooklyn or Manhattan that will sell a cheap LAN tester (something like this, where you plug something in one end and something else in the other and it lights up and checks each pin) tomorrow morning? Any good electronics stores? Online searches at Radioshack and J&R seem to yield nothing but a $150 tester kit, which quite frankly is overkill for me.

Thanks!

Electronic Catan

jasondigitized — Fri, 04 Sep 2009 05:37:32 -0800

I want to create a customized Settlers of Catan board. For the purposes of this question, it could also be a custom Monopoly board. I want the pieces ( cities / hotels ) to light up when they are placed on the board. I know I would put LED's in each piece, but besides that, I am not sure if or how I could power up the LED's. I am not an electrical engineer, but magnets, watch batteries or inductive charging sound good to me. Help me make an awesome electronic board game!

Help me find a great handheld GPS for Geocaching!

PetiePal — Wed, 02 Sep 2009 06:21:20 -0800

I'm looking to buy a personal handheld GPS unit mainly for hiking and geocaching. Recommend an awesome model for me! So this fall I intend to do a lot of camping, hiking, trekking and geocaching. I'd like to buy a handheld GPS unit for the geocaching bit.

What's the best around? Garmin? Other brands? Don't want to break the bank (not looking to spend $200+) but I want something that's good quality, good battery life and will hold up well. Something preferably in color would be nice too. Thanks!

Looking for Berlin's Akihabara

elpapacito — Tue, 25 Aug 2009 09:05:55 -0800

Few hours after work travel in Berlin and looking for local Akihabara or good electronics store. Any place close to S/U-bahn is ok.

How do I cook a 65-degree egg in my own house?

d. z. wang — Mon, 24 Aug 2009 20:35:48 -0800

sous-vide-Filter: I have a pot of water and I can buy an immersion heater or aquarium heater, but how do I control it to maintain an arbitrary temperature 40-100C within 1 degree, for cheap? External themostats for homes and microbreweries and aquaria seems to top out at 32C, and cost upwards of 50$. Scientific water baths and ovens cost $800+. And my oven is not accurate enough. The immediate purpose of this setup will be to cook an egg at 65C, but after that I may branch out to meat. For this reason, a big vat of boiling methanol is not appropriate, even though it would maintain 65C quite nicely.

The ideal solution will cost less than $50-$100 and involve lots of equipment I already own or which will be useful to have around afterwards.

What is the best universal charger to reduce cable clutter, esp while travelling?

shalam — Mon, 24 Aug 2009 14:26:05 -0800

What is the best universal charger to reduce cable clutter, esp while travelling? Equipment that I need charged:
1. Macbook Pro
2. Nikon D70 battery
3. NiMh batteries for flash unit etc
4. Canon camcorder
5. iPhone
6. Scansnap scanner - portable
7. sony ericsson phone

cheers.

Help me sell stuff knowledgably

dance — Fri, 21 Aug 2009 09:03:33 -0800

I'm about to start work in an electronics shop (mobile phones, hifis, computers etc) and would love some tips. I want to make the transition as smooth as possible both for myself and my trainer. I haven't kept up to date with developments in the IBM-PC hardware area for a number of years as I now a mac and therefore lost interest. My Windows and Mac software knowledge is fine. But what about all the new acronyms and developments in the HiFi, gaming, TV, home cinema worlds? Does anyone have any reference that will help me be a good salesman?

And if anyone has any general tips for working in this field I would be grateful.

Thanks!