Eas 199b Pdx Homework Solutions

EAS 199B - Required Equipment

Each student in EAS 199B will use the Arduino Experimenter's Kit and software that was used in the prerequisite course, EAS 199A. Each student will also need the additional equipment listed below.

For your convenience, a list of local and on-line suppliers is provided at the bottom of this page.

EAS 199B — Required new equipment for EAS 199B

In addition to the Arduino Experimenter's Kit, each student will also need to purchase the following equipment.

1. Standard 20x4 Character LCD
Minimum Quantity: One per student
Purpose: To provide visual feedback on status of Arduino programs, especially for the fish tank.
Source: PSU Bookstore -- go to the textbook desk in the basement. $18
Tutorial for wiring: Follow the LCD tutorial at Lady Ada's Arduino tutorials. Instructions on building a wiring harness to connect the wiring harness to the Arduino will be given via class notes.
John Boxall has an alternative tutorial that describes both the parallel and serial interfaces to the LCD panel. If you want to try the serial interface you will need a Serial Peripheral Interface (SPI) device like the i2c/SPI character LCD backpack from Adafruit or the Serial Enabled LCD Backpack from Sparkfun or use the Three-Wire Interface described in Boxall's tutorial.
Approximate Cost: $18-24
2. Breadboard
Minimum Quantity: One per student
Purpose: To provide room to implement additional circuits for controlling the fishtank. We recommend a breadboard with about the same number of holes as the one shown in the picture (840 tie-point breadboard).
Source: Various sources, including Radio Shack (catalog number 276-002 for $14.99) and Omnitron Electronics (part number BB-9831 for $2.97).
Approximate Cost: $3 - $20
3. Drill Bit Set: 1/6 to 1/4 inch
Minimum Quantity: One per team
Purpose: You need to have your own bits to drill whatever size hole you want as you complete your projects for the remainder of the year. Remember to only drill in a shop environment (not on surfaces that you are apt to damage).
Source: Various sources, including most hardware stores. You don't need an expensive, high precision, set for this class.
Approximate Cost: $5 - $15
4. DC Power Supply: 12 V, 1.5 Amp (minimum)
Minimum Quantity: One per team
Purpose: The power supply is necessary for the solenoids and heater used in the fishtank system. At least a 1.5A at 12 VDC capacity is needed.
Source: Various sources including Radio Shack or other electronics supply stores. Amazon has a big selection.
Adafruit has a slightly underpowered 12V 1A supply and a beefy 12V 5A supply.
The desktop model on the right (above) is model number PS-28 available at www.omnitronelectronics.net.
Approximate Cost: $5 - $30

EAS 199B — Recommended new equipment for EAS 199B

The following items are recommended for each fish tank — one set per group of four students. These items should be either bought together or not at all. They will allow you to separately control the power to your electronics and the pump. This will be very handy — but not necessary — when you debug the equipment.

Note that there are variations on the electrical box with switches. One solution – option 5a – is to use the electrical boxes and switches common to 110 VAC household wiring. Another solution – option 5b – is to use a project box and rocker switches for a more geek gadget feel.

5a. Electrical box and dual switch
One per fish tank
Purpose: The dual switches allow you separately control the power to the pump and to the electronics.
Note that there are two switches on the single switch unit. This is unlike the most common kind of light switch.
Source: Local hardware stores.
Approximate Cost: $9 for the double switch and $3 for the box and cover
5b. Project box and switches
One per fish tank
Purpose: The individual switches allow you separately control the power to the pump and to the electronics.
There are many types of rocker switches and toggle switches. Make sure you get an on/off type rocker or toggle switch, not a a momentary type switch.
Source: Electronic supply stores. Note that rocker switches and toggle switches can be recycled/reused from old electrical equipment. Before you throw any electronic equipment away, deconstruct it to salvage parts.
Approximate Cost: $5 to $7 for the project box and $3 to $7 each for the switches.
6. Terminal blocks for two circuits
One per fish tank
Purpose: The terminal block allows connection of the input power to the always-on side of the switches. Details of installation are provided in the class notes. The terminal block also provides strain relief in case someone accidentally yanks on the power supply cord.
Source: Local autoparts stores or electronics stores like Radio Shack.
Approximate Cost: $1 to $3
7. Barrel Jack
One per fish tank
Purpose: To make it easy to disconnect the power supply so that the fish tank can be transported. Make sure the gender of your barrel jack is opposite of the gender of your power supply. In other words, if the power supply has a male plug, the barrel jack should be female, and vice versa.
Source: Local electronics stores or scavenged from used electronics, or purchased from Adafruit.com or part number 2099121 at (for a 2.5 mm jack) from www.jameco.com. or part number 159506 (for a 2.1 mm jack).
Approximate Cost: $2

Local Sources of Electronics and Electronics Equipment

The student section of the IEEE has a store that is open a few hours per day. Note that the hours are posted as a PDF file that has different names for each term. It's likely, therefore, that this link will become stale. If the link is broken, you can (probably) find the current hours from a link on the home page for the student section of the IEEE.

Here is a list of local businesses that sell electronics and tools useful for this class and all sorts of related tinkering:

Used Electronics/Surplus Electronics


Mail order and On-line

Local Hardware Stores

  • Winks Hardware, 200 SE Stark Street -- an excellent source of hard-to-find hardware
  • Pearl Hardware, 1621 NW Glisan St.
  • Parkrose Hardware 10625 NE Sandy Boulevard -- an excellent source of hard-to-find hardware
  • Lowes, Home Depot, etc.

Some online suppliers:

Using Arduino

This page provides links to class notes and on line instructions for the Arduino microcontroller platform.

All students in EAS 199A are required to purchase their own Arduino board, which is part of the Sparkfun Inventor's kit. The kit is available from the Textbook Information Desk at the PSU Bookstore.

See below for advice on avoiding pin 0 and pin 1 for digital I/O.

Arduino Home

From the Arduino home page:

Arduino is an open-source electronics prototyping platform based on flexible, easy-to-use hardware and software. It's intended for artists, designers, hobbyists, and anyone interested in creating interactive objects or environments.

On the Arduino web site you will find

The getting started guide has detailed pages on installing the Arduino IDE:

Manual for the Sparkfun Inventor's Kit

The manual for the inventor's kit can be downloaded in low resolution (1 MByte) or high resolution (8 MByte) format. The manual provides an overview of the hardware and software necessary to program an Arduino, and it includes twelve tutorial lessons on building circuits that are controlled by Arduino programs.

Adafruit Tutorials

Adafruit Industries designs and sells electronics kits and components. Limor Fried, the founder of Adafruit, has written an excellent set of tutorials on learning arduino. If you were going to start with one tutorial, start there.

John Boxall's Getting Started with Arduino

John Boxall has an extensive set of tutorials called Getting Started with Arduino

Books on Arduino

Do not use digital Pin 0 or Pin 1 unless you really need to

There is a subtle problem caused by connecting a wire to either digital pin 0 or digital pin 1 if you are also trying to communicate with the Arduino via the USB cable. Pin 0 and pin 1 are used for serial communication in addition to the USB connector on the board. The details are in the Arudino Reference Manual


The use of pin 0 and pin 1 as serial communication lines can lead to confusing behavior that may cause you to jump to the conclusion that your board is fried.

Here is the scenario.

Suppose you write a program and build a corresponding circuit that uses pin 0 or pin 1. The first time you download the program via the USB cable, everything works (assuming, of course that both your program and circuit are correct). Next you make some changes to the code and try to download the update. The IDE gives you an error (need actual error message here) that has nothing to do with the change in code or with the health of your board. The first program is running, and because there is a non-floating voltage on pin 0 or pin 1, the Arduino is thinking someone is sending it data (or waiting for data) over the serial line. Therefore, the Arduino blocks additional communication.

The solution is either (1) power cycle the Arduino or (2) temporarily disconnect the wires from pin 0 and pin 1 and download the program.

So ... it's a good idea to avoid using pin 0 and pin 1 unless you need to.

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