Download Question 7 - TheGreengineersEcotainment

Evan Hernandez
Pawel Klim
Jamie Schuberth
Jill Shah
Krusha Shah
1. Question 7: What are the components necessary for a complete, sensor-based, inputoutput electrical system?
a. How much voltage is required of the load for minor outputs like beeps, noises,
and arrays of LEDs?
i. A regular red LED has a voltage drop of between 1.63 V and 2.03 V. For
colors besides red, the voltage increases, though not by much. The
maximum voltage for any color is white, requiring a voltage drop of 3.5 V.
ii. http://www.livescience.com/19654-beep-digital-sounds-annoying.html
iii. http://web.archive.org/web/20070809062214/http://www.nichia.co.jp/spec
ification/appli/electrical.pdf
iv. A small speaker for use in robotics projects generally has a power rating
of 0.5W, which is fairly low and can easily be accommodated in a project
only requiring some sort of beep or noise upon receiving some stimulus.
v. https://www.sparkfun.com/products/9151
b. What are the resistance specifications on standard LEDs, small speakers, and
other common minor outputs?
i. A basic red LED light has a resistance of 125 Ohms, and a small speaker
has an impedance of 8 Ohms. These are very small values relative to the
types of electronics we will be using, so they should be able to be powered
by a simple battery or a plug in the wall.
ii. https://www.sparkfun.com/products/9151
iii. https://www.sparkfun.com/products/9590
c. What are examples of common, cost-efficient sensors, including motion sensors,
light sensors, line sensors, and so forth?
i. https://www.sparkfun.com/products/8630 - This is a “PIR” motion sensor,
costing $9.95. When it detects any movement in its range of vision, its
alarm pin will go from a high to low signal. It can be combined with many
others like it in a row. This is because when multiple ones are hooked up
together in a chain, tripping the alarm on one sensor will set off every
other one at the same time. This could prove useful, as the range of space
through which a bottle cap might fall could be bigger than what one sensor
could take care of.
ii. https://www.sparkfun.com/products/10245 - This is a load sensor, also
costing $9.95. When a weight is placed upon its sensor, it will reflect this
in its outputs. This could also be used to possibly detect a bottle cap being
thrown away. For example, the sensor could be hooked up to some sort of
plate, which would then detect anything thrown onto the plate. While this
would possibly be more difficult to build at first than the motion sensor, it
would much easier to maintain and troubleshoot, as motion sensors tend to
be finickier and less consistent than load sensors.
Evan Hernandez
Pawel Klim
Jamie Schuberth
Jill Shah
Krusha Shah
d. How are the aforementioned sensors applied with efficiency and a low-level of
error? Is there any specific technique that ensures greater accuracy, like with a
motion sensors level of detection?
i. LEDs are much greener and more efficient than most other types of lightproducing electronics, so from the start they are better to use. The only
special consideration that has to be taken when using this type of light is in
dimming, as many LEDs are not designed to be able to dim smoothly and
thus suffer from flickering and other quirks. One should check and make
sure that an LED is certified to work with dimming before trying to do so
with it.
ii. http://www.bulbs.com/learning/ledfaq.aspx
e. Generally, how is computer programming utilized to determine interaction
between sensors and outputs, if at all?
i. The easiest way to start programming with digital electronics-type sensors
and outputs is using the Arduino series of circuit boards, hooking them up
to LEDs and load and sensors and so forth. This is then combined with the
Arduino IDE, a piece of software for the easy programming of digital
electronics projects. The simplest board for this use is the Arduino Uno,
which is designed for simplicity and versatility in electronics projects. By
wiring the various components of a project, such as load sensors and
LEDs, to the board, and in turn connecting the board to a computer,
procedures and behaviors can be programmed into the system using a
version of the BASIC language
ii. http://arduino.cc/en/Main/Products