Tagged Questions

9
votes
2answers
366 views

Why exactly 470 or 1k Ω? (to prevent damage of output pin)

Quote from the Arduino tutorial, section Digital Pins: Short circuits on Arduino pins, or attempting to run high current devices from them, can damage or destroy the output transistors in the ...
2
votes
2answers
193 views

leds in parallel, switched with NPN transistors

I have the following circuit designed to drive 3 PWM pins off a 3v3 Arduino Pro Mini -- one pin for each of R, G, B in this set of 5 RGB LEDs. simulate this circuit – Schematic created ...
8
votes
4answers
41 views

Is there any way that the Arduino board can get damaged by using a buzzer without a resistor?

I want to use a standard piezo buzzer on one of the Arduino Uno's analog pins without the use of a resistor. Will connecting this be a problem for the Arduino board? Why?
3
votes
2answers
289 views

Do I need to use a resistor with a microswitch to limit current for an Arduino Uno?

I'm using an Arduino Uno to control a small robot and I'm starting to add micro-switches as bump-sensors. I know that when I'm creating a circuit with LEDs I need to use resistors to limit the current ...
0
votes
1answer
119 views

Can I add resistors?

How can I achieve 10k resistance? I just got my photocell in the mail, totally forgot the 10k resistor. The thing is I have a lot of different resistors in the span 1, 10, 27, 37,56, 68, 82, 100. Is ...
3
votes
2answers
110 views

Reset pin on ATtiny84/85/2313 clarification

I have two questions that I was hoping someone could clarify with a quick True/False. When using the ATtiny85/85/2313 the reset pin is connected to a 10k resistor which is connected to VCC. When ...
4
votes
3answers
131 views

Arduino Question regarding the resistor

I was instructed to set up a resistor on the negative side of the LED and pulling it to ground. I'm confused why we are implementing a resistor on the backside (negative end) of the LED. I always ...
3
votes
1answer
188 views

Pull down resistor for Arduino input to read LOW when no voltage from switch

I'm building the Arduino spaceship interface from the project book and everything works fine. It involved connecting 3 Arduino outputs to 3 leds, and 1 Arduino input to the a switch. For a photo of ...
0
votes
2answers
193 views

Anode RGB LED Arduino Hookup Confusion

I'm having a really hard time getting this RGB Led working with my arduino. First i'll describe my setup (schematic) , and then i'll show you the code I have. I have 5 volts going into the second pin ...
0
votes
1answer
668 views

TLC 5940 PWM driver blank input and pull-up resistor

I've read some of the data sheet for the TLC 5940 and it states the following about the BLANK input: Blank all outputs. When BLANK = H, all OUTn outputs are forced OFF. GS counter is also reset. ...
0
votes
1answer
65 views

NTE2013 base inputs

I have an NTE2013 which I want to use with an Arduino. I may be driving the base pins directly off of the Arduino or perhaps off of a 74HC595. Should I use resistors between the outputs and the base ...
8
votes
1answer
4k views

Do I really need resistors when controlling LEDs with Arduino?

I'm just trying out Arduino Uno for the first time with 2 blinking LEDs on a breadboard. All the tutorials on the Internet seem to use a resistor. I do know the function of resistors, but does it ...
0
votes
1answer
403 views

Wheatstone circuit not functioning

I have 3 dummy strain gauges suffering no strain (all 120 ohms, G.F=2.1) and the fourth (same characteristics) is meant to pick up torque at 45 degrees on a rod. It has been verified on an external ...
0
votes
2answers
403 views

Amplifying strain gauges on an arduino

I have 4 standard mild steel foil strain gauges bonded to a steel bar in a wheatstone bridge arrangement. They are implemented into a circuit with the INA 125P amplifier. I only manage to use about a ...
1
vote
2answers
551 views

Netduino/Arduino to Variable Resistor

Hi Guys — I'm a developer and I want to have a bit of fun with electronics. I don't know much about it so I have a bit of a question. I'm pretty sure this can apply to Netduino, Arduino or any other ...
0
votes
1answer
1k views

EMF Detector Sensitivity

A fun little project I've been working on is an EMF detector using my recently acquired Arduino. It is based off of the guide at http://www.aaronalai.com/emf-detector, primary differences being my own ...
0
votes
2answers
1k views

120v variable resistor controlled by 5v?

I want to do some work with automating christmas lights later this year and my friend and I think relays may be the way to go. After a little more thought, I think it would be cooler if the lights ...
1
vote
1answer
371 views

What kind of resistors do I need to use in this Canon remote switch, if it is possible at all with the P2N2222A transistor I have?

I'm a total electronics n00b set out to create an intervalometer for my Canon EOS 350D camera which seemed super simple from the outset, but I got a bit blocked with creating a switch using a ...