Engineer's Chat V1: Keeping the World Running one Problem at a Time
30 replies, posted
I could have sworn there was an engineer thread a while ago, but it seems to be long gone.
[IMG]http://i.imgur.com/M10aaP2.png[/IMG]
[B][Civil, Mechanical, Chemical, Electrical, Interdisciplinary (Others)][/B]
Anyway, discuss things here relating to engineering; problems, questions, projects, discussions, or whatever.
I guess I'll start with the OP:
I planned and constructed this walkway a couple years ago for my school as my eagle project.
~11 yards of concrete, a lot of road-base, broke a main water line, almost hit the gas main, and I decided not to tackle rebar, and ended up using wire mesh instead.
[IMG]http://i.imgur.com/aDIjyps.png[/IMG]
My most recent work of note is being part of the control system design team for this beauty:
[img]http://images.gizmag.com/inline/lego-rolls-royce-engine-3.JPG[/img]
Im just sitting here waiting for my 3d printer to warm up.
Work as a plastics and injection moulding specialist in a sorting machine company.
Okay so I've got a lil question for the Electrical Engineers here. I'm trying to get 2000 mA of power from [URL="http://www.fstoplights.com/aw-10280-3-7v-180mah-rechargeable-lithium-cobalt-lico-battery/"]this battery[/URL]. Now granted, the battery does 180 mAh, wayyyy less then what I need. I've been toying around trying to find out ways to increase my current, without adding another battery in parallel since space is kinda an issue in this build (all this has to fit in a Hula Hoop with an ID of 5/6"). I have an idea of hooking up 12 5V caps in parallel to each other so each stores a current of 180mA, but I'm not certain what'll happen when I hook them all up to another to connect to the circuit again. I'm split between it either adding them all up and giving me an output of 2060 mA which would work, or it'll all connect and stay at 180 mA. Anybody got any ideas?
Also sorry if some of my ideas sound wrong or inconsistent, I just started to really study this stuff yesterday. I've never studied studied electrical engineering before so I'm probably wrong on a few things.
[QUOTE=Mikesword221;47036532]Okay so I've got a lil question for the Electrical Engineers here. I'm trying to get 2000 mA of power from [URL="http://www.fstoplights.com/aw-10280-3-7v-180mah-rechargeable-lithium-cobalt-lico-battery/"]this battery[/URL]. Now granted, the battery does 180 mAh, wayyyy less then what I need. I've been toying around trying to find out ways to increase my current, without adding another battery in parallel since space is kinda an issue in this build (all this has to fit in a Hula Hoop with an ID of 5/6"). I have an idea of hooking up 12 5V caps in parallel to each other so each stores a current of 180mA, but I'm not certain what'll happen when I hook them all up to another to connect to the circuit again. I'm split between it either adding them all up and giving me an output of 2060 mA which would work, or it'll all connect and stay at 180 mA. Anybody got any ideas?
Also sorry if some of my ideas sound wrong or inconsistent, I just started to really study this stuff yesterday. I've never studied studied electrical engineering before so I'm probably wrong on a few things.[/QUOTE]
Just a heads up - what you are planning will probably utterly ruin the battery and probably won't achieve what you want. Adding capacitors might get you a brief spike of the current you want but nothing more. What on earth are you trying to do? Could you not get away with a normal AAA battery?
Just a second year civil/structural engineer here, finished my january exams. Got a hydraulics, soil mechanics, steel/concrete design, highway engineering and advanced solids exam to do next, shitting it would be a understatement
[QUOTE=Mikesword221;47036532]Okay so I've got a lil question for the Electrical Engineers here. I'm trying to get 2000 mA of power from [URL="http://www.fstoplights.com/aw-10280-3-7v-180mah-rechargeable-lithium-cobalt-lico-battery/"]this battery[/URL]. Now granted, the battery does 180 mAh, wayyyy less then what I need. I've been toying around trying to find out ways to increase my current, without adding another battery in parallel since space is kinda an issue in this build (all this has to fit in a Hula Hoop with an ID of 5/6"). I have an idea of hooking up 12 5V caps in parallel to each other so each stores a current of 180mA, but I'm not certain what'll happen when I hook them all up to another to connect to the circuit again. I'm split between it either adding them all up and giving me an output of 2060 mA which would work, or it'll all connect and stay at 180 mA. Anybody got any ideas?
Also sorry if some of my ideas sound wrong or inconsistent, I just started to really study this stuff yesterday. I've never studied studied electrical engineering before so I'm probably wrong on a few things.[/QUOTE]
Just a heads up, you need to get your units straight.
Current is measured in Amps, which is the rate at which charge moves through the wire.
The amount of current a battery can deliver [B]for a sustained amount of time[/B] is measured in Amp-hours (Amps*hours). [B]​For example, a 10mAh battery can provide 10mA for 1 hour.[/B]
To find the energy storage in a battery you need to use the voltage which is voltage*current*time. This is measured in joules but the units for that are (volts*amps*seconds).
Additionally power is the rate at which energy is transferred and is measured in Watts. A Watt is one Joule/second, or as you could see from the last example, this can be represented by voltage*current (Amps*Volts).
It would be handy to use these two relationships:
V=I*R or voltage=current*resistance (ohm's law).
P=I*V where P is power.
With that out of the way, for your application specifically, a capacitor would not be a good idea. The way they work, they store charge which decays exponentially when "released". This would actually give you less current at first as you powered on your circuit and then do fuck all for you, if they were simply hooked up in parallel with the battery. They would maintain the current after the battery is disconnected for a short period of time, but that wouldn't be useful.
Idk what exactly you're making, but if you want to increase the current, you need to see about either decreasing the resistance in your circuit, or increasing the voltage (by putting batteries in series or getting a higher voltage one).
Yeahhhhh. I'm still kind of lost. When you say voltage*current*time=energy storage, what exactly defines the current? Would it be the mAh the battery has? Also what I'm trying to do is make a Hula hoop that lights up and is programmable. Currently I'm using [URL="http://www.adafruit.com/product/1376"]this led strip[/URL] (Gonna need about two and a quarter strips) and [URL="http://www.mouser.com/ProductDetail/RF-Digital-Wireless/RFD22102/?qs=sGAEpiMZZMsrChSOYEGTCe5yjmp0UHJLk6Cfi%2fAxwzY%3d"]this board[/URL] and I'm trying to power it with that battery, but I've only got a tinyyyy bit of space to work with.
i'm an engineer(ing student)
doin computer and electrical engineering it's really cool
just had a quiz on digital logic about sum of products and product of sums. aced that shit
[QUOTE=Mikesword221;47040224]Yeahhhhh. I'm still kind of lost. When you say voltage*current*time=energy storage, what exactly defines the current? Would it be the mAh the battery has? Also what I'm trying to do is make a Hula hoop that lights up and is programmable. Currently I'm using [URL="http://www.adafruit.com/product/1376"]this led strip[/URL] (Gonna need about two and a quarter strips) and [URL="http://www.mouser.com/ProductDetail/RF-Digital-Wireless/RFD22102/?qs=sGAEpiMZZMsrChSOYEGTCe5yjmp0UHJLk6Cfi%2fAxwzY%3d"]this board[/URL] and I'm trying to power it with that battery, but I've only got a tinyyyy bit of space to work with.[/QUOTE]
mAh is the number of milliamp-hours the battery stores (it's a unit of charge). If the battery has 180 mAh, it means it can deliver 180 mA for 1 h, or 1 mA for 180 h. Capacitors store charge according to the formula Q = I * t (charge = current * time, as current is just flowing charges), but they won't do what you want. Capacitors store charge to release later, you can't use them to just 'get' extra charge out of your batteries. The only real solution is to either use more batteries, or batteries with more charge capacity (mAh).
[QUOTE=Falcqn;47040435]mAh is the number of milliamp-hours the battery stores (it's a unit of charge). If the battery has 180 mAh, it means it can deliver 180 mA for 1 h, or 1 mA for 180 h. Capacitors store charge according to the formula Q = I * t (charge = current * time, as current is just flowing charges), but they won't do what you want. Capacitors store charge to release later, you can't use them to just 'get' extra charge out of your batteries. The only real solution is to either use more batteries, or batteries with more charge capacity (mAh).[/QUOTE]
mAh isn't really a unit of charge - strictly speaking it's a measure of how long the battery can sustain moving units of charge at a given rate....
Batteries have a maximum discharge rate to consider as well as their capacity for energy storage. It is conceivable (although unlikely) that his battery could provide him 2000mA but it would do so for only 180/2000 = 0.09 of an hour or about 5 minutes
[QUOTE=Mikesword221;47040224]Yeahhhhh. I'm still kind of lost. When you say voltage*current*time=energy storage, what exactly defines the current? Would it be the mAh the battery has? Also what I'm trying to do is make a Hula hoop that lights up and is programmable. Currently I'm using [URL="http://www.adafruit.com/product/1376"]this led strip[/URL] (Gonna need about two and a quarter strips) and [URL="http://www.mouser.com/ProductDetail/RF-Digital-Wireless/RFD22102/?qs=sGAEpiMZZMsrChSOYEGTCe5yjmp0UHJLk6Cfi%2fAxwzY%3d"]this board[/URL] and I'm trying to power it with that battery, but I've only got a tinyyyy bit of space to work with.[/QUOTE]
There is absolutely no way that battery however will power what you are asking. For one it doesn't even provide the full 5V the LEDs want so they are probably going to be barely visible. I'm not sure you will need the full 2000mA you are asking for - if you play it careful you could get away with half of that.
You might find a 5V LiPO could sustain what you want from it - but be incredibly careful they are prone to fire/explosion if you don't charge them correctly.
Currently taking Thermo and Diffy Q as a Chem E major. They've mentioned Steam Engines like 4 times already I think I'm really going to enjoy this class. (I must admit I'm still taking the wee-little baby Chem E courses, the fun doesn't start until next year)
I am however putting off taking Cell Bio. I don't care if I have I have to stay an extra summer just to get the credit for it, I do NOT want to compete with the Med Students trying to get their A's in a subject I can barely keep my eyes open for.
Hello everyone, EE (student) from [URL="http://en.wikipedia.org/wiki/Bauman_Moscow_State_Technical_University"]that little place[/URL]. Doing all kinds of ee fun from schematics to layout to programming, right now I'm buidling an inertial navigation system with GPS and Pitot tubes for small fixed-wings from scratch, gonna be a glorious 6-layer PCB with 6/6 design rules, two MCUs and a [URL="https://www.dropbox.com/s/vsnf3gs6b5whhta/%D0%A1%D0%BA%D1%80%D0%B8%D0%BD%D1%88%D0%BE%D1%82%202015-02-02%2002.42.36.png?dl=0"]fat analog part [/URL] for pressure and temp sensing
Anyone has questions about Яussian education (or electronics), shoot
[QUOTE=metallics;47025694]
[img]http://images.gizmag.com/inline/lego-rolls-royce-engine-3.JPG[/img][/QUOTE]
What were your tasks in it?
[QUOTE=revzin;47056283]Hello everyone, EE (student) from [URL="http://en.wikipedia.org/wiki/Bauman_Moscow_State_Technical_University"]that little place[/URL]. Doing all kinds of ee fun from schematics to layout to programming, right now I'm buidling an inertial navigation system with GPS and Pitot tubes for small fixed-wings from scratch with, gonna be a glorious 6-layer PCB with 6/6 design rules, two MCUs and a [URL="https://www.dropbox.com/s/vsnf3gs6b5whhta/%D0%A1%D0%BA%D1%80%D0%B8%D0%BD%D1%88%D0%BE%D1%82%202015-02-02%2002.42.36.png?dl=0"]fat analog part [/URL] for pressure and temp sensing
Anyone has questions about Яussian education (or electronics), shoot
What were your tasks in it?[/QUOTE]
I've had two mains roles in the project so far, first one was actual systems engineering so creating/maintaining the requirements documents for the control system, making sure the design is robust enough to meet standards etc. I obviously didn't look after the whole thing, I had a few specific functional areas I looked after such as turbine case cooling control.
I then moved on to what is called Hardware/Software Integration test where as the name implies I was testing the hardware and software combinations of the engine controller on a rig.
I'm not sure whether this question belongs here or elsewhere but I give it a shot.
I'm graduating this year from highschool and I want to go from IT to a little more 'physical' stuff. Teachers tell me that I should study engineering at college and I find these kind of stuff fascinating. I am good at math, physics, programming, have little knowledge in modelling etc... Anyway I don't know if I should really take mechanical engineering, considering I have some skills in IT and haven't tinkered with mechanical stuff. Is it a problem or should I just take computer engineering and be stuck on a path that I'm bored of?
[QUOTE=ichiman94;47068019]I'm not sure whether this question belongs here or elsewhere but I give it a shot.
I'm graduating this year from highschool and I want to go from IT to a little more 'physical' stuff. Teachers tell me that I should study engineering at college and I find these kind of stuff fascinating. I am good at math, physics, programming, have little knowledge in modelling etc... Anyway I don't know if I should really take mechanical engineering, considering I have some skills in IT and haven't tinkered with mechanical stuff. Is it a problem or should I just take computer engineering and be stuck on a path that I'm bored of?[/QUOTE]
Pick the one you will enjoy the most - if it's the mechanical course the enjoyment factor will outweight the lack of previous experience.
It will pay dividends when you come to get a job - the market is tough and employers are looking for engaged and enthusiastic people.
[QUOTE=ichiman94;47068019]I'm not sure whether this question belongs here or elsewhere but I give it a shot.
I'm graduating this year from highschool and I want to go from IT to a little more 'physical' stuff. Teachers tell me that I should study engineering at college and I find these kind of stuff fascinating. I am good at math, physics, programming, have little knowledge in modelling etc... Anyway I don't know if I should really take mechanical engineering, considering I have some skills in IT and haven't tinkered with mechanical stuff. Is it a problem or should I just take computer engineering and be stuck on a path that I'm bored of?[/QUOTE]
I had pretty much the same situation and I went into electrical, now happily combining lowest level electronics with programming. Knew close to nothing about electronics, save for Ohm's Law when I decided to get into it, and now I'm considered a very capable 'student' EE in our "Department of Electronics Design and Manufacture". What I wanted to convey that with determination which comes with enjoyment from your profession you'll learn years in months, you'll develop that mystical 'engieneering intuition' and kick everyone's asses
Also, I am very positive they won't want PROFESSIONAL MECHANICAL ENGIENEER EXPERIENCE from ya, the point of engineering education is that they give you that or at least try to make that impression
Depends on what you really want mate, In my school at least, the Mechanical Engines have all the fun, and get to take classes where they can get Machine Shop experience (so they basically learn the basics of making things). EE's have their own fun but it's mostly with circuit/coding,; there's an EE thread in the programmers forum so I suggest you ask there if you want to learn more about that.
In terms of careers, engineering mostly boils down to either R&D, management, or consulting.
Frankly, it sounds like you would fit in well with Electrical Engineering, especially considering any engineering is less about memorization, and more about being able to adapt and apply, so even if you aren't directly taught something you'll be able to pick it up faster then someone who took just computer science.
(Also if it sounds like I know what I'm talking about, keep in mind I have no IRL experience and my descriptions are from a Chemical Engineering Student looking in from the outside).
i got chem-cad,
anyone know any tutorials, and or if its legal to simulate uranium refinement in this
[editline]3rd February 2015[/editline]
[QUOTE=TheTrainRider;47047839]Currently taking Thermo and Diffy Q as a Chem E major. They've mentioned Steam Engines like 4 times already I think I'm really going to enjoy this class. (I must admit I'm still taking the wee-little baby Chem E courses, the fun doesn't start until next year)
I am however putting off taking Cell Bio. I don't care if I have I have to stay an extra summer just to get the credit for it, I do NOT want to compete with the Med Students trying to get their A's in a subject I can barely keep my eyes open for.[/QUOTE]
thermodynamics, (i'm assuming the gen-engineer class) is fun, but the real fun starts in CME thermo, where things get....non-ideal!
im in seperations right now which is like the applied theory from chem-e thermo which builds off of thermo, but we haven't gotten hard into distillation separation yet
[QUOTE=Sableye;47071332]where things get....non-ideal!
im in seperations right now which is like the applied theory from chem-e thermo which builds off of thermo, but we haven't gotten hard into distillation separation yet[/QUOTE]
Ayyy "non ideal" :v:
I'm pretty sure they divi up what you consider CME Thermo into other classes like the Materials Class and the Kinetics class. The CE department has it's own thermo course separate from the Mechanical Engines, but I don't know where the differences begin to show.
Are Nuclear Engineers allowed in this thread?
[QUOTE=RIPBILLYMAYS;47071579]Are Nuclear Engineers allowed in this thread?[/QUOTE]
Go right ahead, I don't see anything really wrong with it. I'm pretty sure it falls under interdisciplinary anyway, so you're good.
Also if anyone has any tips or links that are helpful for others that they want to supply for the OP, feel free to do so.
Third year mechanical engineer here.
[QUOTE=Mikesword221;47036532]Okay so I've got a lil question for the Electrical Engineers here. I'm trying to get 2000 mA of power from [URL="http://www.fstoplights.com/aw-10280-3-7v-180mah-rechargeable-lithium-cobalt-lico-battery/"]this battery[/URL]. Now granted, the battery does 180 mAh, wayyyy less then what I need. I've been toying around trying to find out ways to increase my current, without adding another battery in parallel since space is kinda an issue in this build (all this has to fit in a Hula Hoop with an ID of 5/6"). I have an idea of hooking up 12 5V caps in parallel to each other so each stores a current of 180mA, but I'm not certain what'll happen when I hook them all up to another to connect to the circuit again. I'm split between it either adding them all up and giving me an output of 2060 mA which would work, or it'll all connect and stay at 180 mA. Anybody got any ideas?
Also sorry if some of my ideas sound wrong or inconsistent, I just started to really study this stuff yesterday. I've never studied studied electrical engineering before so I'm probably wrong on a few things.[/QUOTE]
[url]https://philihp.com/blog/2011/diy-led-hula-hoop/[/url]
What you're doing has been done before, looks like you might have more success with RC car batteries.
[QUOTE=metallics;47040566]mAh isn't really a unit of charge[/QUOTE]
Q = I*t
mA is a unit of current
h is a unit of time
1 mAh = 10^-3 A * 3600 s = 3.6 C
???
Yes, batteries have a maximum discharge rate, but if we're talking units mAh is for sure a unit of charge.
First year mechanical engineer here. I would like to ask, to all my colleagues out there: how are your career contents presented to you? which courses do you get on first year? what's the average duration of the career in your countries?
I've got 5 years here, as a minimum, and on the first 2 years all of my classes are about basic stuff (algebra, Physics, chemistry and calculus) but no one directly about the career per se (mechanical design, structures, etc).
[QUOTE=Adeptus;47077529]First year mechanical engineer here. I would like to ask, to all my colleagues out there: how are your career contents presented to you? which courses do you get on first year? what's the average duration of the career in your countries?
I've got 5 years here, as a minimum, and on the first 2 years all of my classes are about basic stuff (algebra, Physics, chemistry and calculus) but no one directly about the career per se (mechanical design, structures, etc).[/QUOTE]
A lot of figuring out whether you like the content in your career path is mostly independent studying and research. Once you actually take some of your engineering classes, you'll start to see more of what you like about it. In regards to what you should take in the beginning is just to start with all the lower division general education (math, physics, and other required courses) so that you have a baseline to work with once you get into engineering classes. It'll be easier for you to switch majors if you feel like doing so, and you'll be able to take in the material at an easier pace to where you understand the content and learn how to apply all of your built up knowledge from the core classes.
[QUOTE=Mikesword221;47040224]Yeahhhhh. I'm still kind of lost. When you say voltage*current*time=energy storage, what exactly defines the current? Would it be the mAh the battery has? Also what I'm trying to do is make a Hula hoop that lights up and is programmable. Currently I'm using [URL="http://www.adafruit.com/product/1376"]this led strip[/URL] (Gonna need about two and a quarter strips) and [URL="http://www.mouser.com/ProductDetail/RF-Digital-Wireless/RFD22102/?qs=sGAEpiMZZMsrChSOYEGTCe5yjmp0UHJLk6Cfi%2fAxwzY%3d"]this board[/URL] and I'm trying to power it with that battery, but I've only got a tinyyyy bit of space to work with.[/QUOTE]
Weeee late reply
So basically, what you're trying to do probably isn't going to work with that battery. It's one of those pissy AA lithiums that generally have nasty amounts of internal resistance - you won't get a 2 amp draw out of it for any decent amount of time at 180mah anyway.
What you should look at is finding more efficient LEDs, and preferably not strips. If I'm reading correctly, these LEDs are drawing something to the tune of 60ma each - pretty high draw.
And to answer your question - The maximum current defined by the battery depends on the resistance of the circuit and the internal resistance of the battery. The battery you linked seems to be a mystery brand with no datasheet(grr) so it's hard to know, but being a small lithium you probably wont be impressed - or anywhere near low enough for 2 amps continuous draw.
[QUOTE=TheTrainRider;47071567]Ayyy "non ideal" :v:
I'm pretty sure they divi up what you consider CME Thermo into other classes like the Materials Class and the Kinetics class. The CE department has it's own thermo course separate from the Mechanical Engines, but I don't know where the differences begin to show.[/QUOTE]
ya we have materials balances, seperations, kinetics, and a bunch of other classes, but there is a special chemical engineer's thermodynamics which explores various gas models, and focuses on non-ideal gas models and things like azeotropes and teaches you to recognize when to use ideal/non ideal conditions and pick a proper modeling technique
So I got back from an Engineers Without Borders meeting (I highly recommend looking into it if you are a student) and we got a presentation from a guy trying to make a new platform to show off student projects. He's making a website(?) called Atlas where students can show off their engineering projects as they progress through them. Its in beta right now but he said it should hit 1.0 in the Spring. If anyone wants to try it out, you can make an account at [url]https://betaversity.com/login/[/url]. I don't have much project experience since I'm just a freshman, but I thought it might be neat for someone with more engineering history.
Also the EWB project I'm assisting in is a rainwater catch system for an impoverished school in rural Bolivia. Right now I'm translating the field manual into Spanish so the students and faculty can maintain the water system they already have.
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