How to know what to use(?)

Other Hardware General Electronics
1

Hello, it's been a while since I've been here. Please forgive the title as I couldn't think of any other way of wording it haha...

My problem is basically this. Since my last post a bizillion years ago I've expanded my programming knowledge pretty far, and I've read most all the documentation on the Arduino website so I feel I'm pretty much set there. However, my electronics is not up to snuff. I understand what most of the basic components do and such, but I don't really know when I should use something, or what specific "version" of something I should use. I see people throwing out statements like "oh just use your standard 1343hjsusnt346 (gibberish) and you'll be fine."

For example,I have just started a research project for honor's Physics and I have several tentative areas of research. The one I would most like to go forth with is building a quadcopter and programming it accordingly. I wanted to start off real basic and see how I could control the speed of a motor from my Arduino.I thought to myself, "need motor, need pot,need..." and then I realized I have a need for resistors, but what kind? And where? I continued to read random posts here and there and realized that had I tried running my setup as is without using a transistor and diode I could have sent my Uno to an early grave. So now I am pretty much terrified of hooking anything up to my Uno except for my LED and making it blink on and off...

So my question is, where can I acquire this knowledge? How do I know what to use, when to use it, and where? Obviously a knowledge of what things "do" hasn't been enough to let me continue with this project and I'm pretty much lost at this moment. If you could give me books, videos, any kind of resources it would be a tremendous help to me. I'm really excited to do things with my Arduino that don't involve a fire extinguisher and the electric waste bin.

Thanks for all your help!
-Adrian

2

Well you have a learning curve ahead of you. Don't let that discourage you, because there is plenty of fun along the way, but be prepared to adjust your expectations regarding the quadcopter because it may take some time to get there.

I'll relate my personal experience. Decades ago when I was in high school, they offered three courses, one called Basic Electricity and then Electronics I and II. So I took those, but I also read everything I could in magazines like Popular Electronics and Radio Electronics. These featured DIY projects varying from simple to more complex. I spent a lot of time building circuits. Even reading about the ones that I wasn't interested in building helped advance my knowledge. I burned up a few components here and there, but not an undue amount really. I went on to get an EE degree but what I had done on my own was invaluable, it helped a lot then, and still does.

The question about books to read, etc. has been asked before here on the forum, so use the search facility to find those threads.

Specific to Arduino and microcontrollers, learn breadboard an Arduino or use inexpensive clones like the Boarduino (Adafruit), Diavolino (Evil Mad Science), or the Bare Bones Board/Really Bare Bones Board from Modern Device. Learn to burn the bootloader onto a raw ATmega328P microcontroller -- use the ArduinoISP sketch or get an In-Circuit Serial Programmer (ICSP).

These clone boards are simple and there is really very little to hurt on them. Worst case, if you fry the MCU, you can replace it with another one, burn the bootloader, and you're only out two or three dollars. Buy several replacement MCUs just to have on hand. You may be amazed at how fast they get used up in projects, even if none get burned up!

Get a decent multimeter. Spend $50 or $60 on it. It will serve you well for a very long time.

Just a random stream of consciousness, hope it helps. Have fun, get messy, make magic smoke (well, occasionally) :smiley:

3

Adrian,

I think the Arduino is a great tool to learn electronics. Most the electronics in the tutorials are all quite basic. If you work your way through all the tutorials you find here, you will get a good idea of how all the building blocks work. Most project's I start, I go back to one of the tutorials I did and start with one, or sometimes two.

I started with a kit from Make called the Ultimate Microcontroller Pack, it has everything to do most all the tutorials. There are several others out there that make these kits. I have added to my collection of components over time one by one. Once you learn how to use each component, you now have the building blocks to put it all together. After you do an example, make some modifications to it, it's a great way to learn.

If you look through the Arduino web pages, you will find about everything you need. Here is a good page with links to tutorials:

Late Addition One more thing I think is important, take good notes. If you make a modification, make a note in the sketch of what you modified and save it so if you want to use it again, you remember what you did. I also have a note book, the kind with graph paper in it. I take time to write down what I did, and draw a sketch or wiring diagram. It's been a great resource when making new projects.

Live life on the edge, start wiring up some projects!!

Have fun,

Dave

4

When i heard about Arduino I had already started learning about regular electronics... So i guess I was lucky enough in that respect to understand more about hardware first.

Just look up a few websites with circuits, start off with a resistor and led, then a transistor or a diode then maybe an IC, try to understand the circuit schematic, learn what the components are basic electronics will do you fine for a lot of circuits when it comes to using Arduino..

Work your way through that.

5

"oh just use your standard 1343hjsusnt346 (gibberish) and you'll be fine."

I know how you feel, but really if you tackle one issue at a time it becomes simpler.

If you isolate down what you are trying to do, the solution narrows down. Eg. do you want to switch power, amplify a signal, regulate voltage to (say) 5V, detect a low voltage, drive a speaker, etc.

Once you have that answered you are usually down to a certain "sort" of device (eg. a transistor) and then the issue becomes things like: how much power does it need to drive, what sort of input are you giving it, that sort of thing.

If you are doing something specialized (eg. amplifying radio frequencies, or switching 5 amps) then you will be looking for a more narrow spec. If not, "general purpose" devices will probably suit you.

You can always do some research (generally there will be lots of examples) and if you just aren't certain post a proposed solution and ask what people think.

6

Some things, like a light bulb, are voltage controlled. Give them a proper voltage and they don't care much what the available current is (they will self-limit). That's why a half-amp light bulb doesn't explode when you screw it into a circuit with a 20A (40 times the amperage!!) circuit breaker.

Other things, like LEDs and transistors, are current controlled: give them a proper current and they don't care much what the voltage is (within a reasonable range). So when you see a circuit peppered with resistors, many of them are probably protecting transistors, LEDs, or similar components from conducting excessive current and burning themselves out.

Then it becomes a matter of learning which components are current controlled, and figuring out what value of resistor to protect them with (using Ohm's law based on how much current you want to flow).

Tip: the Arduino's output pins are transistors. As such, they are not self-limiting and can be burned out with excessive current if you connect them to something else that's not self-limiting either (or has too high of a self-limit).

I'm still a newbie though. I look at a circuit and think "what the heck is XYZ doing there". Some of it seems simple, +, -, resistors resist current, capacitors store/release current, transistors switch current on and off, LEDs convert current to light, diodes only let current flow one direction, but... when you start stacking those things together in various ways, electricity doesn't always follow a simple model. My problem is, I haven't learned all the "rules" yet, so when someone uses a rule that I'm not familiar with, their circuit seems to violate the rules I do know. So if someone knows a good place to learn these "rules" I'm all ears.

7

Pick up a book like "Electronic Principles" by Albert Malvino.

And then pick one up called "Semiconductor Circuit Approximations", also by Albert Malvino.

Learn Ohm's Law, Kirchoff's Current and Voltage Laws, learn your way around series-parallel circuits, learn about resistance, reactance, and impedance.

8

Specific to your project I'd discourage you from attempting a quadcopter. While you could probably manage to copy the available code to drive these (MultiWii, Ardupilot) you need at least a minor in math to really understand it. With respect to the hardware needed to build one you'll be spending about $300 -- and there's a lot of trial and error and tuning involved to get it right. You start finding things like your 20A ESC which is only putting out 10A or your frame isn't stiff enough and starts vibrating causing it to crash into a tree. It's a lot of frustration.

9

Wow, thanks everyone for the amazing and prompt feedback. I'm sorry I couldn't reply earlier as I was held up by school and family duties. Anyway, I've taken the advice to search for books already posted in other threads and I've found a good amount of books to work through and they've been enjoyable so far. I also took the advice pertaining to my current project and decided to scrap the quadcopter for the time being seeing its level of complexity, time consumption, and money needed. Now I am at a loss for what to do for my research project, but I have come up with a few neat hobby projects that I would like to start :smiley: (a collapsible "paper lantern" with programmable color that lights up when held in the hand with no physical buttons).

I will definitely be coming back to this forum with more questions in the near future, but for now I just need to do some project inspiration google-fu. Thanks for all the help everyone! Hopefully I'll hear from you again in the next weeks :]