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Topic: Arduino newbie (Read 1 time) previous topic - next topic

Jul 12, 2012, 05:31 pm Last Edit: Jul 13, 2012, 04:08 pm by arduiner93 Reason: 1
Hello! I just bought the arduino uno rev3 and completed the blinking example, plus i used an external led on pin 13 with the small leg on the gnd pin, run the same code and both leds blinked as expected.
I am about to buy some hardware however i have no idea about electronics, so i would be greatful if someone would give me little info on
what to buy to start led projects like led arrays etc. As far as i know i will need a breadboard(kind? size? price?), some leds(i got some covered) wires(what kind?)
resistors(what kind?).

Also i have a small display with 14 pins(as far as i searched most people use 16 pins at least so i don't know if i can make use of it), 8 resistors(560   560R   Green, blue, brown, gold
532? - 588?),some buttons and switches. In the near future i will post some photos of my hardware.

Thank you!
(I could not find any better section for this topic, if it is on the wrong part of the forum let it be moved.)

Photos of my current gear:

A board
http://postimage.org/image/kdqoi0jul/
http://postimage.org/image/hyawy4mud/
LCD Display(14pins)
http://postimage.org/image/xhgfs0yun/
LEDS-Resistors(as i said above)
http://postimage.org/image/4r22wegsl/
Switches-Buttons
http://postimage.org/image/4toec4sjh/
http://postimage.org/image/546so2z0h/

johnwasser

For most any project you can find many examples and tutorials with a Google search:

http://lmgtfy.com/?q=arduino+led+matrix+tutorial
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Ok i ordered some basic things except for the jumper wires.
Question: I have a computer power supplier that won't be used anymore.
Is it possible that i cut the small cables and use them as jumper wires or is it different from the usual ones?

MichaelMeissner

#3
Jul 26, 2012, 09:52 pm Last Edit: Jul 26, 2012, 09:58 pm by MichaelMeissner Reason: 1

Ok i ordered some basic things except for the jumper wires.
Question: I have a computer power supplier that won't be used anymore.
Is it possible that i cut the small cables and use them as jumper wires or is it different from the usual ones?

It depends on the size of the wires in the pc.  Maybe they will fit the Uno, maybe not.  I had some hook-up wire that would fit some boards, and not others.  So I got the various collections of 22 gauge jumper wires, and everything works.  For wiring, you really want different colored wires so that you can follow the circuits better.

Note, you will also need to strip the ends of the wires.  If you are going to be doing a lot of wire stripping (probably not at first), you might want to invest in better wire strippers than your usual pair of needle nose pliers.  But if you are just stripping a few wires, any pliers (or even a knife) will do.

If you live in the USA, Radio Shack sells solderless jumper wires for $6.29 (http://www.radioshack.com/product/index.jsp?productId=2103801&retainProdsInSession=1).  While you can probably get such jumper wire kits cheaper via the internet, you might not want to wait 1-2 weeks.

Oh, and have fun by the way!  :)

Thank you for the fast response!
I think i will give it a try since they can be used even if it does not fit the uno.
As for the future i think i will buy from the local store, as i will probably have the components by tommorow.

Thanks i will post as soon as i get my first project running :)

Cables are "fat", i guess i will buy from the store and finally have a project moving on :smiley-fat:

Ok just got the jumper wires!
Tried a simple led project on my breadboard like this.

The actual code is the same with the blink example but pin has changed to 12.
That resistor is 220 ohms.
The led  is blinking, however when i added a 470 ohm resistor instead of that 220 ohm it would blink the same bright.
Why is that? Shouldn't the brightness decrease? I tried pulling off the resistors in both cases while the led was blinking but no difference.
Even if i didnt put any resistor it would blink the same.

WizenedEE

The blue wire going under the resistor is not correct -- no current will flow through the resistor if there's an easier path (like through the wire)

Thank you i understood it and just fixed it!  :)

Ok after experimenting with leds and buzzers I gave it a go with a hobby motor specifically this.
Before i even started i was confused since i could not find anyone on google powering up such a motor.
Correct me if i am wrong, as far as i understand i can only power it to a fixed speed since there is not the third yellow wire which allows you to control its speed.
So if i want to power it AND control its speed do i need to use any kind of transistor or a bridge (dont really know what each does or is used for)?
And finally, lets say it will only run on a specific speed. Will the speed be determined by the resistor i will use? For example the bigger resistor i use the slower it will run because of the current block. Am i correct?

johnwasser


So if i want to power it AND control its speed do i need to use any kind of transistor or a bridge (dont really know what each does or is used for)?


Since a DC motor generally draws more than 40mA if you power it with 5V so you can't hook it to an Arduino output pin directly.  For loads above 5V or above 40mA you can use a transistor to act as a switch: http://www.electronics-tutorials.ws/transistor/tran_4.html  This is sufficient to turn the motor ON and OFF.  If you use one of the six PWM pins you can use analogWrite() to turn the power on and off quickly.  This allows you to control the average power and thus the motor speed.

If you want to run the motor in both directions you need an H-Bridge.  The easiest way is with an Arduino Motor Control Shield which you can find by Googling.
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