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Trash Talk - electrical engineering

Cheese - Sat Sep 27, 2008 6:50 am
Post subject: electrical engineering

awhile ago i was messing around with electrical engineering and circuit design, only simple stuff really. so i found my stuff lying around in a closet, and have been messing around some more.

anyone know anything about this, or know a good place to find some simple schematics?

been looking around some, but the internet is a big place =(
seems like something you guys might know about...

Dr Brain - Sat Sep 27, 2008 10:31 am
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I've got my bachelor's degree in computer engineering, which is a branch of electrical engineering. EE is one of the largest engineering fields. It encompasses everything from programming FPGAs to semiconductor physics.

What exactly are you trying to build? The simplest (while still being fun) circuit is to connect a battery, resistor and LED. Using a 9 volt battery, a 1K ohm resistor (brown, black, red, gold) is probably your best bet. 700 ohms is better if you can find one, but you won't see much difference in LED brightness. I don't generally get my circuits from online, so I don't know what links are good. Also, what components do you already have?

If you like programming, I'd recommend using an AVR or PIC microcontroller. I can give you some getting started links if you're interested.

Samapico - Sat Sep 27, 2008 12:42 pm
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I studied in industrial electronics, and I'm doing a bachelor in automated production engineering; so yeah, I worked with that stuff.
Something interesting to build would be the Snes Box... always wanted to make one

But last I heard, the drivers didn't work with XP

http://www.tolaris.com/snes-to-parallel/
http://www.geocities.com/ammarini/the_box1.htm

Though the only thing close to electrical engineering in these is soldering diodes

Bak - Sat Sep 27, 2008 11:58 pm
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<3 FPGAs

Blocks - Sun Sep 28, 2008 2:03 am
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I am thinking that the kind of electronics you want to involves making cool stuff, and a good site/merchant that focuses on embedded systems (the quickest way to make cool stuff) is < http://www.sparkfun.com >.

Their tutorials are especially good: http://www.sparkfun.com/commerce/tutorials.php

I highly recommend learning how to use EAGLE (http://www.cadsoft.de). It's a schematic capture program and PCB layout tool.

In regard to your request for schematics, I'd suggest designing your own simple circuits!

Dr Brain - Sun Sep 28, 2008 8:25 am
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If all you care about are results (and not fully understanding the circuit), 555 timers are common and fairly easy to wire up. Just google 555 circuits and you'll get plenty of hits.

Cheese - Sun Sep 28, 2008 5:04 pm
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thanks
and im a little past a battery and a led, but im still limited because i only have 1 transistor to work with ;_;
i care about understanding the circuit, results are almost as important

no interest in working with ICs
not terribly interested in making PCBs either, ive got a breadboard, its enough for me

and with sparkfun, im not putting my electrical projects ANYWHERE NEAR my computer...

to anyone that doesnt know already:
im looking for different ways to connect capacitors and resistors and leds up to do different things, etc.

rootbear75 - Sun Sep 28, 2008 8:10 pm
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if you want something fun, get those electrical circuit kits that come with everything from a toy store or hobby shop or something. those are usually fun

Samapico - Sun Sep 28, 2008 8:19 pm
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Well you could do some blinking circuit or something... Capacitor charges up, discharges through transistor, powering up the LED. Charge / discharge time adjusted with R * C.
Been a while, but I'm pretty sure you can do that without anything else.

If you'd get a 555, you could do much more. You could do that blinking easily. And with a few other chips, like counters, you could do an alarm clock... minus the alarm... unless you plug in a speaker on there as well.

But with just capacitors, resistors and a transistor, you can't do much.

Dr Brain - Sun Sep 28, 2008 9:09 pm
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You can't do much beyond lighting LEDs with only one transistor unless you have some decent bench equipment like a function generator and an oscilloscope (which will cost you many hundreds of dollars). So get some ICs, get more transistors, or get happy with LEDs.

An analogy: it's like someone telling you they want to do stuff with computers but aren't willing to use an operating system.

Cheese - Mon Sep 29, 2008 3:00 am
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what if i bought more transistors? =P

Blocks - Mon Sep 29, 2008 5:01 am
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Cheese wrote:

what if i bought more transistors? =P

So about 50 years ago, people started experimenting with "more transistors," and the IC was born. Seriously, don't limit yourself.

Dr Brain - Mon Sep 29, 2008 6:22 am
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Your local RadioShack will sell you a 556 (two 555s in a single IC) for $2. Get a solderless breadboard too, if you don't already have one.

Anonymous - Mon Sep 29, 2008 9:09 pm
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Cheese wrote:

, ive got a breadboard, its enough for me

Dr Brain - Tue Sep 30, 2008 6:48 am
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In lab we built something like this: http://www.uoguelph.ca/~antoon/circ/RedAlert1.html

It came out decently. Annoying part was being in lab with 20 other people trying to make the same noisy circuit. You shouldn't have that problem, at least.

Quan Chi2 - Fri Jan 16, 2009 1:21 am
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Dr Brain wrote:

I'm an EE and CE major. I'm interested in these starter links you have.

Dr Brain - Fri Jan 16, 2009 6:43 am
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Here's a good page to start with:

http://avrwiki.com/wiki/index.php/Your_First_AVR_Order

I highly recommend the STK500 if you're even remotely serious. It's worth every penny of its $80 price tag. Don't bother with the atmega32's it suggests. They're an older part and fairly "expensive". I'd suggest looking at the atmega128's or atmega164p's instead. They should be close to 1/2 the price of the atmega32 with many more features. The atmega324p is a direct replacement, but generally overkill.

avrfreaks.net is a good page for community support.

This page: http://imakeprojects.com/Projects/avr-tutorial/ is decent for a programming introduction, but I wouldn't follow its advice for hardware choices.

Quan Chi2 - Fri Jan 16, 2009 7:51 pm
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Dr Brain wrote:

Great. Thanks.

I always see guys stressed out over programming these. I don't know why they are important at this point. I was on IRC and a computer scientist that took some EE courses says that he uses PICs all the time at work.

Are PICs and AVRs common in the creation of advanced robots(Artificially intelligent ones)? I imagine that microprocessors are used instead. I saw some YouTube videos on PICs where they controlled motors.

I think I already answered my own question... lol

Dr Brain - Fri Jan 16, 2009 9:14 pm
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8-bit microcontrollers aren't used as the central processors in higher robots, but you'll still find them as part of various sensors and subprocessors (because they're simple and inexpensive).

All of the things you learn from an AVR will still apply to any other microcontroller. Sure, the assembly language may be slightly different, but all of the high level stuff will be the same.

Samapico - Sat Jan 17, 2009 6:31 am
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microcontroller? high-level? wut?

My only experience with a microcontroller is making some assembly stuff to program this: http://www.youtube.com/watch?v=53RsWAAQYN8&feature=channel_page

Quan Chi2 - Sat Jan 17, 2009 5:08 pm
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We had to program one of those types of robots in our first semester, Samapico. It was great. It's the type of programming I'd like to do more of. However, that programming was definitely high level as far as programming languages go. The language we wrote in was C++ and we had no exposure to assembly.

CaptainPoopface - Mon Jan 19, 2009 3:54 am
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Arduino makes some great little microcontrollers, programmable in a subset of either C or C++. They are cheap and very flexible. You can hook them up to your computer with USB, then interface with the hardware (LEDs, switches, etc.) on your breadboard. I know you said you were looking for something more fundamental, but I think it's really the quickest, easiest way to get into it.

I do not recommend assembly programming. It is painstaking, and quite difficult to debug sometimes.

Check out some things you can do with Arduino here. I learned on a breadboard and a HC12 microcontroller (programmed in asm), and it was a major hassle compared to the Arduino.

Samapico - Mon Jan 19, 2009 7:53 am
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CaptainPoopface wrote:

Arduino.

Quote:

Debounce: read a pushbutton, filtering noise.

Nice... The pushbuttons on our robot were so sensitive, they would trigger 2 or 3 interrupts each time we press them :/

Dr Brain - Mon Jan 19, 2009 10:07 am
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I don't recommend writing assembly directly (at least not to start with), but it's usually helpful for debugging to look at the assembly generated from your C code. That means you have to have at least a passing familiarity with the various assembly commands.