Voltage divider, variable resistor, pull-up, pull-down….???
External pull-up resistors
There are various ways to wire or sew external pull-up resistors:
Diagram of a Pull-Down resister for a switch
You need a pull-up or pull-down resister when you want to read a contact switch or button (i.e. push button). If you have pull-up resister, you will see 0V(LOW) when you push the button. If you have pull-down resister, you will see 5V(HIGH) when you push the button on your digital pin reading. Here is a diagram showing why you need a pull-down resister.
Internal Pull-Up Resistors
For the longest time I had no idea that I could simply set internal pull-up resistors using a single line of code! But the Atmel chips that arduino uses have internal resistors that can be toggled on or off for every digital and analog input pin (except A6 and A7 on some boards).
Digital
For setting the internal pull-up resistors for digital input pins, the code will look like the following:
pinMode(2, INPUT);
digitalWrite(2, HIGH); // turn on internal pullup resistor for digital pin 2
*NEW*: pinMode(2, INPUT_PULLUP);
Analog
For most of our fabric sensors using velostat the internal 20 K Ohm pull-up resistors of the Arduino are just fine. To set these you’ll need to include the following lines of code in the setup function of your Arduino sketch. The analog inputs 0-5 can be addressed as digital outputs using the numbers 14-19:
pinMode(A0, INPUT);
digitalWrite(14, HIGH); // set internal pullup resistor for analog pin 0
*NEW*: pinMode(A0, INPUT_PULLUP);
Understanding Voltage Measurement
Ohm’s Law: V = I x R
Voltage divider:
Diagrams explaining voltage divider and pull-up resistor:
Links
>> http://arduino.cc/en/Tutorial/AnalogInputPins
>> http://arduino.cc/en/Tutorial/DigitalPins
The following CNMAT and Wikipedia entries cover all the important explanations of why you need and how to place pull-up or pull-down resistors.
>> http://cnmat.berkeley.edu/recipe/how_and_why_add_pull_and_pull_down_resistors_microcontroller_i_o_
>> http://en.wikipedia.org/wiki/Pull-up_resistor
The second line is drawn upward from some point on
the right slanting line. Note down all the problems and report them to
your professional handyman that is about to get the system repaired.
We take pride in providing you clean service professionals who reach on scheduled
time.
I’ve loaded your site in Several totally different web browsers and I must say this website loads a lot quicker then most. Would you mind emailing me the company name of your hosting company? My personal email is: noreen_shapiro@gmail.com. I will even sign up through your own affiliate link if you would like. Thanks
Hurrah, that’s what I was searching for, what a stuff! existing here at this weblog, thanks admin of this web site.
Good day! My partner and I often publish guest articles for other blog site owners to help increase
exposure to our work, as well as provide excellent
content to website owners. It truly is a win win situation!
If you are interested feel free to e-mail me at: tiablakely@gmx.
de so we may discuss further. Appreciate it!
I am really enjoying the theme/design of your site. Do you ever run into any browser compatibility issues?
A couple of my blog readers have complained about my site not working correctly in Explorer but looks great in Chrome.
Do you have any solutions to help fix this issue?
my web page; news :: Florene ::
Wow! This blog looks exactly like my old one!
It’s on a completely different subject but it has pretty much the same layout and design. Superb choice of colors!
Presenting diamond engagement ring is a tradition which became in
practice from the Romans in 13th century and it is most
common in Christian marriages. A carat is a fifth of a gram,
there are, therefore, five carats to a gram and a carat
can be divided into ‘points’ of which 100 points constitutes the carat weight.
Africa, South Africa and Australia are places from which
yellow diamonds are mined.
Here is my webpage: jewelers.uk [educatorsites.net]