[QUOTE=An Draoi;49017924]I'm currently trying to build a stirling engine and an alternator with the hopes of being able to construct the two as a single unit, thus heat->stirling engine-> electricity.
However I'm not very good at it ;_; I can't figure out how to make a crankshaft for the life of me. I've tried using a metal wire hangar, but it was too curvy. My current attempt is having fashioned one from modelling clay. My goal is to do it with as many DIY materials as possible.
Furthermore, I don't entirely understand the basic principle and concepts of an alternator, just that they exist and function. Can anyone explain them or link me to somewhere where I can figure it out better? Thanks![/QUOTE]
First, just use lumber. Lumber is available literally EVERYWHERE. You can't travel 30 miles in any direction that isn't pure wilderness and not find a hard-ware store in America these days. Here in New Mexico, we have 3 "major" hardware stores that sell lumber [B]that I'm aware of[/B]. There's a couple of small towns that are 10 minutes away, they're both right next to each other (split between the New Mexico/Texas border), and their combined population is less than 3,000 people. They still both [I]each[/I] have their own lumber-providers. It's also easy to work with with cheap/basic tools. Power drills and drill bits made freely available thanks to the industrial efforts of China (who I like to call "Cheapistan" in terms of eBay purchases) that there's little excuse to not have one, or at least have easy access to one, and a basic hand-saw can be found literally anywhere. I've seen them in [I]convenience stores[/I], ffs. :v:
As for alternators, if you've ever toyed with electro-magnets in school or just for fun as a kid, you've seen that passing electric current through a coil of wire creates a magnetic field. Well, it also works in reverse: moving a magnetic field around a coil of wire (or vice-versa, depending on design) will create an electrical current in the wire, meaning you can generate power. The amount of power generated is dependent on the size of the coils and the number of windings, as well as the strength of the magnetic field used.
[QUOTE=An Draoi;49017924]I'm currently trying to build a stirling engine and an alternator with the hopes of being able to construct the two as a single unit, thus heat->stirling engine-> electricity.
However I'm not very good at it ;_; I can't figure out how to make a crankshaft for the life of me. I've tried using a metal wire hangar, but it was too curvy. My current attempt is having fashioned one from modelling clay. My goal is to do it with as many DIY materials as possible.
Furthermore, I don't entirely understand the basic principle and concepts of an alternator, just that they exist and function. Can anyone explain them or link me to somewhere where I can figure it out better? Thanks![/QUOTE]
Google for "How does an electric generator work". There ough to be more than enough good explanations out there.
My new soldering iron came today. I almost went with a Hakko iron, but it was about $20 over my budget. I went with a weller wlc100 station and I bought an ST4 tip to go with it!
[QUOTE=Zero-Point;49018514]First, just use lumber. Lumber is available literally EVERYWHERE. You can't travel 30 miles in any direction that isn't pure wilderness and not find a hard-ware store in America these days. Here in New Mexico, we have 3 "major" hardware stores that sell lumber [B]that I'm aware of[/B]. There's a couple of small towns that are 10 minutes away, they're both right next to each other (split between the New Mexico/Texas border), and their combined population is less than 3,000 people. They still both [I]each[/I] have their own lumber-providers. It's also easy to work with with cheap/basic tools. Power drills and drill bits made freely available thanks to the industrial efforts of China (who I like to call "Cheapistan" in terms of eBay purchases) that there's little excuse to not have one, or at least have easy access to one, and a basic hand-saw can be found literally anywhere. I've seen them in [I]convenience stores[/I], ffs. :v:
As for alternators, if you've ever toyed with electro-magnets in school or just for fun as a kid, you've seen that passing electric current through a coil of wire creates a magnetic field. Well, it also works in reverse: moving a magnetic field around a coil of wire (or vice-versa, depending on design) will create an electrical current in the wire, meaning you can generate power. The amount of power generated is dependent on the size of the coils and the number of windings, as well as the strength of the magnetic field used.[/QUOTE]
Also, the more current you draw from the generator, the more back magnetic force you produce exerting a reverse torque on whatever is turning the generator from Lenz's law. This means loading down your motor by drawing more power than it can generate will slow down the generator, and thus reduce output current.
[QUOTE=Dolton;49028717]Also, the more current you draw from the generator, the more back magnetic force you produce exerting a reverse torque on whatever is turning the generator from Lenz's law. This means loading down your motor by drawing more power than it can generate will slow down the generator, and thus reduce output current.[/QUOTE]
Did I ever tell the story where it took me 3 weeks and literally writing the mathematical proof of this to convince my design engineer he couldn't run 24v steppers on a 45v peak drivers? Ah, design engineers/project leads. A good one can carry a project far further than anyone thought and make the entire thing run great. A bad one... fuck. Just don't.
back emf is a bitch. Watch out for it, its one of those sneaky little bastards that fuck ups designs if you don't watch out for it. Find a way to limit the power you can pull out based on whats being generated, if you can.
Do you talk about Arduino stuff here or is there a different thread specifically for that?
[QUOTE=Richy19;49032697]Do you talk about Arduino stuff here or is there a different thread specifically for that?[/QUOTE]
Everything to do with electronics and stuff like that goes here, including Arduino.
[QUOTE=Richy19;49032697]Do you talk about Arduino stuff here or is there a different thread specifically for that?[/QUOTE]
Microcontrollers are EE work. What were you you going to talk about?
Well Im awaiting delivery for my arduino, but I wanted to check if this is the right place to talk about projects and such or if there was a Arduino specific thread
[QUOTE=Richy19;49033462]Well Im awaiting delivery for my arduino, but I wanted to check if this is the right place to talk about projects and such or if there was a Arduino specific thread[/QUOTE]
Not really. But there is a subreddit that's pretty good as well. Feel free to post here, I can probably help you with the basic stuff. I'm still working on my arduino project. The Arduino Cookbook is also quite good, btw
How does an LM317T work? I want to use one in my LED array because I can't find any suitable resistors.
If I wanted to limit the voltage to 10.4v or 7.3v and current to 2.1A what would I need to do? Do I just need a potentiometer? My power source is a computer power supply.
[QUOTE=false prophet;49041361]How does an LM317T work? I want to use one in my LED array because I can't find any suitable resistors.
If I wanted to limit the voltage to 10.4v or 7.3v and current to 2.1A what would I need to do? Do I just need a potentiometer? My power source is a computer power supply.[/QUOTE]
LM317T is rated for a maximum of 2.2A (below 15V input) provided you mount it on a good sized heatsink.
You can adjust the output with a standard pot.
[img]http://i.imgur.com/F3HpsLw.png[/img]
Pot is R2, the wiper terminal is connected to one side of the pot so it acts as a variable resistance.
The output voltage is then 1.25V * (1 + R2 / R1) + 50uA * R2
R1 should be fixed at 220 or 240 Ohm
The power dissipation of the regulator is roughly (Vin - Vout) * Iout
How big of a heat sink would you guys suggest I use for this lm317 if 45w will be running through it?
I wouldn't be using a linear regulator for driving LEDs at all.
If I wanted a quick hackjob, I'd have a switching power supply with current-limiting resistors. Probably some readymade LM2596 module from eBay.
If I wanted something that's supposed to keep running for longer than a few days, I'd have a constant-current switch-mode power supply.
[QUOTE=false prophet;49048995]How big of a heat sink would you guys suggest I use for this lm317 if 45w will be running through it?[/QUOTE]
45W through a LM317T will exceed the current limit, use a LM338T or better a switching regulator.
(assuming your using 12V input)
The LEDs I'm using have a forward current of 700mA and voltage varying between 3 - 3.6v and I'll have 15 of them in the array.
Actually No_Excuses posted a schematic for this array, but I'm concerned I might nuke my LEDs. The power supply I am using is just a computer power supply, the 12v rail.
[edit] I have an el cheapo 3v 30mA LED on the 12v rail right now to see how long it will last. I stuck a 330 ohm half watt resistor onto the LED and it's pretty bright but showing no signs of melting.
So I need to construct some power relays for controlling my 3D printer and my internet modem.
For my 3D printer I want to be able to control it from the Rasperry Pi running OctoPi (effectively a print server) being able to turn off the printer itself due to lack of power switch on the printer itself. A normally-open switch is preferred with a 555 monostable timer circuit keeping the relay circuit closed.
And for my internet modem because the internet service at my parent's house is horribly spotty and when my internet does disconnect it takes up to an hour for the firmware within the router to fix itself or 30 seconds if I power cycle it. I'd like for my OpenWRT router to be able to force a restart should issues arise if I'm not there. This one I'd like for the switch to be able to power itself from the mains with something like and ESP8266 (plus ATmega/ATtiny? I'm unsure about using an ESP8266 as the MCU as well) for the router to talk to.
I understand its effectively just a relay tied (power consumption from a GPIO notwithstanding) to a power outlet, and there is very little actual work to be done other than wire it up (and following the electrical code), but I'm not comfortable with working with mains electricity. And from what I can tell pre-made units go for $80 and up.
[QUOTE=Cakebatyr;49052828]So I need to construct some power relays for controlling my 3D printer and my internet modem.
For my 3D printer I want to be able to control it from the Rasperry Pi running OctoPi (effectively a print server) being able to turn off the printer itself due to lack of power switch on the printer itself. A normally-open switch is preferred with a 555 monostable timer circuit keeping the relay circuit closed.
And for my internet modem because the internet service at my parent's house is horribly spotty and when my internet does disconnect it takes up to an hour for the firmware within the router to fix itself or 30 seconds if I power cycle it. I'd like for my OpenWRT router to be able to force a restart should issues arise if I'm not there. This one I'd like for the switch to be able to power itself from the mains with something like and ESP8266 (plus ATmega/ATtiny? I'm unsure about using an ESP8266 as the MCU as well) for the router to talk to.
I understand its effectively just a relay tied (power consumption from a GPIO notwithstanding) to a power outlet, and there is very little actual work to be done other than wire it up (and following the electrical code), but I'm not comfortable with working with mains electricity. And from what I can tell pre-made units go for $80 and up.[/QUOTE]
I'd suggest you to not switch mains, but rather switch the dc output of the supply. As for programming the ESP8266: There are firmwares that implement lua on the ESP, and there are gui tools for easy installation of said firmware. Programming it is really a piece of cake.
I'd do it by programming it with a couple IP adresses (8.8.8.8 for example), and have it ping it once every few seconds. If it doesn't get a reply for a minute, powercycle.
[quote]And for my internet modem because the internet service at my parent's house is horribly spotty and when my internet does disconnect it takes up to an hour for the firmware within the router to fix itself or 30 seconds if I power cycle it. I'd like for my OpenWRT router to be able to force a restart should issues arise if I'm not there. This one I'd like for the switch to be able to power itself from the mains with something like and ESP8266 (plus ATmega/ATtiny? I'm unsure about using an ESP8266 as the MCU as well) for the router to talk to.
[/quote]
If your modem uses a single LED to indicate weather or not it is connected, use that to drive it.
[QUOTE=pentium;49053113]If your modem uses a single LED to indicate weather or not it is connected, use that to drive it.[/QUOTE]
With an external esp you don't have to open up the device and void the warranty.
[QUOTE=DrDevil;49053380]With an external esp you don't have to open up the device and void the warranty.[/QUOTE]
strap a phototransistor in front of the LED ;^)
[editline]sadas[/editline]
No.
no.....
I fucking finished recapping an old CRT monitor and when I plugged it into the test rig there was no blue. Poled around and almost all of the blue analog circuit was dead with no output to the gun. What the fuck did I accidentially kill?
Everything.
[IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/IMG_1631.jpg[/IMG]
How did I miss that?? Three unsnipped leads that shorted against the ground plane and other components. :suicide:
[editline]asdfa[/editline]
HAH! they sure don't make electronics like they used to. It's turned out fine after the leads were snipped.
[IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/IMG_1636.jpg[/IMG]
[QUOTE=DrDevil;49052948]I'd suggest you to not switch mains, but rather switch the dc output of the supply. As for programming the ESP8266: There are firmwares that implement lua on the ESP, and there are gui tools for easy installation of said firmware. Programming it is really a piece of cake.
I'd do it by programming it with a couple IP adresses (8.8.8.8 for example), and have it ping it once every few seconds. If it doesn't get a reply for a minute, powercycle.[/QUOTE]
I can switch the DC output on the printer for sure, that's only a 12V 10A supply. But the power circuitry is built into the modem with only AC input.
Is the international version of the Art of Electronics much different to the US version? How much difference will there be?
I want physical reading material.
[QUOTE=Cakebatyr;49055550]I can switch the DC output on the printer for sure, that's only a 12V 10A supply. But the power circuitry is built into the modem with only AC input.[/QUOTE]
Switching mains with a relay is perfectly safe as long as you put everything inside a box (though I don't usually follow that advice myself :v:)
[QUOTE=false prophet;49055565]Is the international version of the Art of Electronics much different to the US version? How much difference will there be?
I want physical reading material.[/QUOTE]
As far as I can tell, it's exactly the same.
Unless you're talking 3rd edition then I don't know, but I highly doubt it would be any different.
An international 2nd edition is about $30 on ebay.
I'm very inexperienced with electric engineering, but I find it a fun hobby and incredibly useful.
I still have several concerns because I'm afraid I'll destroy my LEDs. They were inexpensive, but still, it's an important project to me because I'll be growing vegetables all winter long with them and I can finally move my seedlings out of my bed room.
Can I use a single resistor in each series to protect my LEDs from burning out?
The formula I'm using to get the resistance is 12v - (3.6v+3.4v+3.4v) / (700mA / 1A)
But what about the wattage rating for these resistors? Is the formula for determining this V * I, so like, 12*(700/1000)? So with all that, does that mean I need a 2.2-3ohm 10W resistors to protect my LEDs from burning up?
And also should I add the forward current of each LED, so instead of 700mA a series of 3 would be 2.1A?
[QUOTE=false prophet;49056348]An international 2nd edition is about $30 on ebay.
I'm very inexperienced with electric engineering, but I find it a fun hobby and incredibly useful.
I still have several concerns because I'm afraid I'll destroy my LEDs. They were inexpensive, but still, it's an important project to me because I'll be growing vegetables all winter long with them and I can finally move my seedlings out of my bed room.
Can I use a single resistor in each series to protect my LEDs from burning out?
The formula I'm using to get the resistance is 12v - (3.6v+3.4v+3.4v) / (700mA / 1A)
But what about the wattage rating for these resistors? Is the formula for determining this V * I, so like, 12*(700/1000)? So with all that, does that mean I need a 2.2-3ohm 10W resistors to protect my LEDs from burning up?
And also should I add the forward current of each LED, so instead of 700mA a series of 3 would be 2.1A?[/QUOTE]
You can run the LEDs on 12V, as long as the current is limited with a resistor you're good.
Assuming the drop of each LED is 3.5V (it doesn't have to be perfect) that means you can reasonably have 3 in each series string for a total drop of 10.5V.
The resistance you need is then (12V - 10.5V) / 0.7A = 2.14 Ohms.
2.2 Ohms is a good standard value, the power dissipation of the resistor is I^2 * R which is 1.078W, so I'd go for 2W resistors, this isn't exactly efficient but it'll do for your application.
How much watts can FM Tesla receiver receive?
Bleh, signals and systems eats up all my time and energy. Here's something that I accomplished for my Uni's student run/funded space program. A fully integrated comms system for our upcoming high alt. balloon:
[video=youtube;exQlcI00hMs]http://www.youtube.com/watch?v=exQlcI00hMs[/video]
Here's what documentation I've made for it so far:
[URL="https://sites.google.com/site/lonewolfscircuits/sitefiles/HAB-III_System_Overview_draw_io_10-13-2015.pdf"]System overview[/URL]
[URL="https://sites.google.com/site/lonewolfscircuits/sitefiles/Power_%26_IO_Board_Overview_Layout.pdf"]Power/IO Distribution Board Layout[/URL]
[QUOTE=LoneWolf_Recon;49065435]Bleh, signals and systems eats up all my time and energy. Here's something that I accomplished for my Uni's student run/funded space program. A fully integrated comms system for our upcoming high alt. balloon:
[video=youtube;exQlcI00hMs]http://www.youtube.com/watch?v=exQlcI00hMs[/video]
Here's what documentation I've made for it so far:
[URL="https://sites.google.com/site/lonewolfscircuits/sitefiles/HAB-III_System_Overview_draw_io_10-13-2015.pdf"]System overview[/URL]
[URL="https://sites.google.com/site/lonewolfscircuits/sitefiles/Power_%26_IO_Board_Overview_Layout.pdf"]Power/IO Distribution Board Layout[/URL][/QUOTE]
"We need the range". You can get several of hundreds of kilometers range with a 10mW 433 MHz transceiver which is like 20 bucks on ebay.
You should also use a second mode of communication that can also be listened to by people without specific hardware, for example APRS. APRS is moderately easy to implement and had wide coverage around the globe. You can't push more than a few bytes of data over it, but it's perfect for regular position updates so you can find the balloon after landing.
[media]https://www.youtube.com/watch?v=ppj3gqUTt9E[/media]
I'm not sure what to say about this.
It's certainly different.
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Electrical Engineering V3
