View source for EGR 224/Arduino Interfacing With Hardware Supplement

The following represents a supplement to the LinkedIn Learning module "[https://www.linkedin.com/learning/learning-arduino-interfacing-with-hardware Learning Arduino: Interfacing with Hardware]" by Zahraa Khalil.  Duke people should go through [https://oit.duke.edu/what-we-do/applications/linkedin-learning Access LinkedIn Learning for Duke] to get to LinkedIn Learning, then you can search for the module (or once you have logged in you can click directly).

For [[EGR 224]], students should first go through the module using a virtual Arduino on Tinkercad and then later go through the process of building the actual circuit with their Arduino kit.  Everything necessary for the circuit is in the kit.

== Going Through the Module with Tinkercad ==
=== Interface with an LCD ===
* Tinkercad has a Circuit Assembly for controlling a 16x2 LCD. Start a new circuit in Tinkercad.  In the components drop down at the top right, select "Starters - Arduino."  Drag an "LCD: Control the text on a Liquid Crystal Display" circuit into your model and follow along with the movie; note that the wiring is already done and matches the wiring in the video.
* Go through the Optional videos in this section.
* Duplicate this circuit in Tinkercad, then change the code in the duplicate to match the "Displaying random numbers and scrolling" section.
=== Interface with a 7-Segment LED ===
[[File:CommonAnode.PNG|thumb|200px|Common anode configuration - notice resistors going from the red rails to the common pins on the 7SD]]
[[File:CommonCathode.PNG|thumb|200px|Common cathode configuration - notice resistors going from the '''black''' rails to the common pins on the 7SD; the code also needs some adjustment since a high pin will now turn a segment on]]
* There is no starter for this in Tinkercad, so you will need to generate this model from scratch.
* For the circuit, instead of having a wire from the middle top and bottom pins of the 7-segment display to the power rails, use a 330 Ohm resistor. If you do not, you will either blow out the 7SD (or later, the chip) when you build the circuit.
* For the last part of controlling the 7SD directly, write subfunctions for each digit to turn on the appropriate sections.
* Tinkercad and your kits have the shift register chip (74HC595) so go through that part as well.
* Once you have this working with the default common '''anode''' display in Tinkercad and in the module, note that your actual 7-segment display in the kit is a common '''cathode''' display.  What you will need to do to get your simulation to work the way it will work on your real circuit is as follows:
** Save your circuit, then duplicate it and give it a new name that indicates you are working with a common cathode 7SD.
** Click on the 7SD and change it to a common cathode 7SD.
** Move the 330 Ohm resistors to go from the common pins of the 7SD to '''ground''' instead of 5 V.
** Either change the 0s to 1s and the 1s to 0s in the dataArray '''or''' replace <code>shiftOut(dataPin,clockPin,MSBFIRST,dataArray[index]);</code> with <code>shiftOut(dataPin,clockPin,MSBFIRST,256-dataArray[index]);</code>, which will automatically invert the bits of an 8-bit binary number.

=== Interface with a Keypad ===
* The keypad on Tinkercad and in your kit is a 4x4 keypad versus a 4x3.  
* For "Combine them all" - the Tinkercad UNO does not have enough pins; you will only be able to do this one with your real-world Mega; watch the videos, though, to see how it all comes together.

== Going Through the Module with Your Kits ==
* Build the circuit and run the code for "Displaying random numbers and scrolling."  Take a video of your LCD displaying some random numbers.
* Be sure to use the correct chip - check the top for "74HC595"for the shift register.
* Build the circuit and run the code that ends with "The shiftOut command."  '''''EXCEPT''''' instead of having a wire from the middle top and bottom pins of the 7-segment display, use a 330 Ohm resistor.  Note that you will not be required to build the direct-drive version of the 7-segment LED.  It is *very rare* to directly drive a 7-segment display because of the number of pins that ties up. Take a video of your 7-segment display counting from 0 to 9.
* Build the circuit and run the code that ends with "Combine them all."   Take a video showing you pushing the various buttons.

== Beyond the Module ==
* Figure out how to make the final circuit above work with the letters "A" through "D" on the keypad.  Take a video showing you pushing the various buttons.  Generally you will use upper case for A & C and lower case for b & d.  You will also be uploading your code for this to Sakai.

== Turning Things In ==
You will need:
* Tinkercad: put the shared links in a text document or in the "Submission" text box on the Sakai assignment when you turn it in; you do not need screenshots since you are submitting the links which will go directly to the circuits.
** Random numbers on LCD
** 7-segment common anode LED with shift register
** 7-segment common cathode LED with shift register
** 4x3 Keypad for LED
* Movies: either attach the movies or put them in cloud storage (Box) and provide links - be sure to share the links with TAs and make sure TAs have access to them.
* Random numbers of LCD
* 7-segment  counting from 0 to 9
* Combine them all using the keypad and displaying on LED and LCD -- if you do this, you do not need a separate video for just the 4x3 keypad but you can include both
* Codes
** Attach the <code>.ino</code> for the Combine them all since that will not be on Tinkercad

You do not need to include anything from driving the LED directly.