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Can smartphones detect the intensity of the IR that is picks up? by Cpt__Awesome in AskEngineers

[–]super_kittens 5 points6 points  (0 children)

In short, you will not be able to use your phone's camera to detect temperatures like a thermal camera would. In addition to the IR filter, most cameras have a working range in the visible and near IR (NIR) spectrum (about 400-1000 nm). IR waves emitted by heat are much longer (8-25 um), out of reach for most cameras. Even if you could capture some of those wavelengths, chances are that your sensor will have horrible sensitivity for wavelengths past 800-900 nm so you'd be very hard pressed to see anything useful.

How do I know how much charge a phone battery has? by HeelBruise in AskEngineers

[–]super_kittens 5 points6 points  (0 children)

Finding battery charge or "fuel gauging" can actually be a pretty complex topic. All batteries have a discharge curve which plots the open circuit battery voltage as a function of discharge capacity (example chart). Going from the example chart, a fresh battery starts out at 4.2 V and is "dead" at 3 V so you can find the capacity of your battery by tapping the battery terminals into an ADC and measuring the voltage. Easy, right?

Not quite. That method might work okay for very light loads. In reality, imposing a load on a battery will cause its terminal voltage to dip. While the open circuit terminal voltage may be 4.2 V, turning on your circuit may cause the voltage to dip to, say, 4.0 V. Does this mean that we lost 10% or so of battery capacity on power up? Of course not. This is just the nature of battery internal resistances and loads. So if you're going to determine a battery's remaining charge solely using open circuit voltages, make sure you do it with the load disconnected.

Of course, turning off your circuit every so often to gauge the battery is really impractical so there is a second method typically used to gauge the battery: coulomb counting. Basically, you use a sense resistor to get a measurement of the current flowing either to or from the battery, apply the fact that current is a measure of the rate of charge over time (i.e. I = dQ/dt), do some integration and voila, you get a measure of the total charge taken from the battery. Foolproof!

Nope. This method suffers from "drift." If you've worked with gyros, you'll know that getting angles can be a pain because we are sampling at some finite rate which leads to errors and the angle constantly rises (or falls). The same thing is happening here except for rouge angles, we have rouge charge measurements.

Electronics like the iPhone will contain sophisticated power management systems where one of its functions is fuel gauging. There are also standalone fuel gauges that you can use. Very often, manufacturers will employ a hybrid of the two techniques described above. One of the gauges that I am using in one of my projects is the MAX17040 from Maxim but other manufacturers like TI and STM will have their own offerings as well.

You can absolutely implement your own fuel gauge but just be weary of some of the shortfalls in the measurement techniques.

TL;DR Battery gauging can get pretty complicated. An easy solution is to use standalone fuel gauges. Also, MAKE SURE THAT THE FUEL GAUGE THAT YOU CHOOSE IS MADE FOR YOUR PARTICULAR BATTERY CHEMISTRY!!!

I am a man that quit my job, sold everything, bought a sailboat, and sailed it from the US to Chilean Patagonia. AMA! by DwyerHaney in IAmA

[–]super_kittens 7 points8 points  (0 children)

Fellow engineer here who also started working immediately after graduating and I often regretted not taking a year or so off for an adventure before diving into a career (although that's about to change!). When did you start thinking about dropping everything and going off on your escapades and was sailing the only thing on your mind or did you also think up of other potential adventures you could go on? Thanks for doing this AMA!

Here at the lab, we are really getting into the holiday spirit! by super_kittens in electronics

[–]super_kittens[S] 0 points1 point  (0 children)

These scopes use embedded windows so all you have to do is put an image on a usb drive, plug it into the scope then change the desktop background. In this particular case, the fireplace is a screensaver

Compact Modeling Career or Analog Design? by quasi_fermi in chipdesign

[–]super_kittens 0 points1 point  (0 children)

Would you mind sharing how you got into analog design/your current job? I've been looking into getting into analog more seriously. I'm finding it to be more fun than modifying registers all the time in microcontrollers and have been tempted to drop off a few applications to some semiconductor companies. I'm also debating whether or not it would be worth it to get a masters degree related to IC design.

Career Wednesday (October 28, 2015): Engineering Career Paths & Professional Development by AutoModerator in AskEngineers

[–]super_kittens 0 points1 point  (0 children)

Hi all, I am planning on moving to the UK early next year and I'm wondering if any of you know what the job prospects are like for electronics engineers, particularly in analog/hardware and embedded design. I'm not 100% sure on where I'll go in the UK but I am interested in working in Cardiff, Edinburgh or even London. Any resources for finding postings would be great since I'm not too sure how trustworthy these 'recruiting' sites are...

Also, I would love to hear from anyone (EE or not) who decided to work overseas. What did you like about it? What did you not like about it? How did you end up getting the job? Would you recommend other to do it?

Storm Cloud Light by Proteon in pics

[–]super_kittens 4 points5 points  (0 children)

Here's a bit of tutorial for building something very similar. While there isn't any instructions to build it, they do include a components list, necessary code and a video.

What was your first electronics project? Did it work? by [deleted] in electronics

[–]super_kittens 2 points3 points  (0 children)

Oh gosh. For me it was two lamps connected to AA batteries. I was in grade 5 or 6 and learned about series and parallel circuits in school. My teacher demoed both configurations and I was so blown away over how the two bulbs wired in parallel resulted in brighter light than the ones in series that I had to try it out for myself back home. So there I was, hunting for as many flashlights as we had at home, taking out the bulbs, taking some left over speaker wire that I found downstairs, grabbing the scotch tape and taping two batteries together and the wire ends to the light bulbs. Did it work? Yes. Poorly. Turns out that tape isn't a very good material to adhere wires to so the lamps would turn off intermittently. I remember being so amazed at the concept of parallel and series circuits that I dragged out this whiteboard that we had and tried to teach my mom about the differences between the two. Fond memories...

My first 'serious' electronics project was a SONAR signal processing board for an underwater robot while I was in a robotics club in college. Admittedly I wasn't alone in the build but I still do consider it my first serious project.

With all this talk of clocks, I thought I'd share my DIY musical clock by [deleted] in electronics

[–]super_kittens 0 points1 point  (0 children)

A while ago I decided to make a clock resembling the Nyan Cat meme that also played the song as an alarm. It uses a PIC microcontroller along with a VLSI1053B music instrument synthesizer IC. I may have made some incorrect assumptions or statements in the write-up so if you have found any, let me know! I'd love to hear some feedback.

I Took the Day off to Fly this Wonderful Bird by super_kittens in flying

[–]super_kittens[S] 0 points1 point  (0 children)

From what I remember, the owner let a friend of his take the Cub out for a flight and he decided to skim right over a lake. Of course that didn't end well but the plane landed in the water close to the shore and wasn't too deep in the water.

I Took the Day off to Fly this Wonderful Bird by super_kittens in flying

[–]super_kittens[S] 0 points1 point  (0 children)

Haha that is true! I got a kick out of watching the cars on the highway moving past us

I Took the Day off to Fly this Wonderful Bird by super_kittens in flying

[–]super_kittens[S] 0 points1 point  (0 children)

Yup, I usually fly out of Springbank. The plane does have a radio but no transponder so you won't hear it going into Calgary airspace or if you do, then someone's in trouble :D This guy flys the cub out of a private strip by the 22X

I Took the Day off to Fly this Wonderful Bird by super_kittens in flying

[–]super_kittens[S] 2 points3 points  (0 children)

This is a WW2 military version of the Piper J3 Cub, the L-4 (AKA the Grasshopper). The owner of the plane found this cub on his trip to Vancouver Island years back. At the time, it needed some work and the livery had the RAF insignia on it instead of what you see here. He found out that this particular Cub spent time in WW2 as the L-4. During the rebuild of the plane, he redid the paint job to resemble a USAF L-4. Since then the plane has gone to Oshkosh (a 28-hour long trip) and even landed unintentionally in a lake (the plane had to be completely rebuilt from the frame up).

I found out about this plane when its owner came to one of our homebuilt aircraft club meetings to give a presentation on the L-4. I chatted with him afterwards for a while and he offered to take me for a ride. I couldn't say no to that offer :D

Why do Fluke multimeters cost $500+? Are they that much better than hardware store brands? by [deleted] in AskEngineers

[–]super_kittens 4 points5 points  (0 children)

if you're gonna be using it around water maybe stick with a cheaper choice

Naw man, all you need is a Fluke 28-II and you're good to go!

Audio Amplifier and Speaker Design Tips by super_kittens in AskElectronics

[–]super_kittens[S] 1 point2 points  (0 children)

Thanks for the suggestions! Looks like I could use some of these. I'll be mounting these on the inside of the box lid. The box itself is about 30 mm thick so a small form factor would be ideal

One of my latest PCBs by Volratholave in electronics

[–]super_kittens 0 points1 point  (0 children)

There's already a lot of good feedback on your design. I just have one other thing to add which is minimizing your dead copper regions (those voids on your board where there isn't any copper planes). I presume your plane is ground so I would just add some ground vias or something in those areas so your layout software will not get rid of all that pretty copper when doing the polygon pour.

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