CCAT solar stereo system/Literature review

Literature Review (Fiona Flores)[edit | edit source]

Review of literature related to sound quality, types of speakers, amplifiers, and wire connections, battery portability, and solar sound system examples as well as the basics of Bluetooth.

Environmental Effects on Sound Quality[edit | edit source]

Varying speeds and frequencies of vibration (sound waves) that move through a space and bounce off of objects create what we perceive as sounds. The types of objects and materials used to construct and decorate a room, such as carpeted or hardwood floors, curtains, and pillows, all have an effect on the sound quality of a speaker. Hard and flat objects, such as wooden floors or cement, cause vibrations to reverberate for a longer period of time then absorbent objects like sponge and pillows that have many crevices and jagged edges. Absorbent environment can cause sound to travel a shorter distance than non-absorbent environments.^[1]

Connecting Amplifiers, Subwoofers, and Stereo Speakers[edit | edit source]

Connecting a Subwoofer to a Home Stereo System[edit | edit source]

Sound systems require multiple parts to have full stereo-sound, including a subwoofer to create deep bass. To connect a subwoofer to a home stereo system, we should use a line-out connection to send a low-frequency, non-amplified signal to the subwoofer. We may need to utilize a RCA cable to connect the subwoofer from the Sub Out or LFE out on a receiver to the subwoofer input jack.^[2]

Connecting a Guitar Amp to a Speaker[edit | edit source]

A guitar amp can connect to another external stereo system using 3 leads or long wires. In order to do this, we will need RCA cables and red and black speaker wires. Red should go to the positive terminal, while black wires should go to the negative one. To make the wires compatible with both external speakers and a guitar amplifier, we will need to strip them of one centimeter of their protective coating, attach shrink tubing to the end of the wires, and then solder metal terminals to the end of them.^[3]

Audio Cables and Battery Portability[edit | edit source]

Cables for Sound[edit | edit source]

Most music uses stereo sound, meaning that it has two audio channels. Some sound systems, called surround sound use more than two audio channels. These common channels can include a subwoofer, front and surround left, as well as front and surround right. Two speaker stereo systems usually connect to these two channels on the left and right sides in order to create sound that moves from ear to ear. The most useful cable for music in stereo is an RCA cable.^[4]

Connecting non-portable speakers to a portable power source[edit | edit source]

To change a non-portable, two speaker sound system into a battery powered one, we will need to take apart the speaker with the volume dial. Inside of most of these speakers there will be a printed circuit board (PCB) and a transformer. The transformer will have a four wire terminal on it that connects to a power source to the PCB. To connect the speakers to a battery powered source, we will need to connect the positive and negative power wires from the terminal to the positive and negative sections of our battery.^[5]

Lead-Acid batteries as a portable power source[edit | edit source]

Lead acid batteries use chemical reactions to store and release electricity. In order to do this, lead acid batteries convert electrical energy into chemical energy, and then release it once again as electrical energy. These batteries produce cheap electricity in comparison to other batteries (2-3 times cheaper), but they are disadvantaged by their low specific energy because of the high atomic weight of lead. Lead acid batteries have been very successful because they are very reliable, easy to produce, and they can deliver large amounts of power.^[6]

All About Bluetooth[edit | edit source]

What is Bluetooth?[edit | edit source]

Bluetooth is a low-power radio band (between 2.400 GHz and 2.483.5 GHz). It is designated by international agreement to be used in scientific, industrial, and medical devices. Many electronic devices already have Bluetooth built in so that they can connect to this same radio frequency, making Bluetooth an excellent way to make a sound system that is compatible with many different devices made by different companies.^[7]

Bluetooth Issues[edit | edit source]

Poor connection and disruptive frequencies can interfere with Bluetooth and cause it to malfunction. Some interfering devices can include: microwave ovens, poorly shielded power lines, 4GHz cordless telephones, wireless security cameras, wireless WiFi speakers and other Bluetooth devices, and cabling and connectors for cable and satellite service. An aux cable can be used in the case of Bluetooth malfunction.^[8]

Bluetooth Compatibility[edit | edit source]

Bluetooth is a standardized radio technology that allows many devices to connect to each other to produce sound and uses relatively low amounts of power, making it useful for a solar powered system. This radio technology belongs to a special interest group (SIG) which makes it available for use on many electronic devices regardless of the company that made them.^[9]

Examples of Solar Powered Sound[edit | edit source]

Some examples of solar powered sound making devices include the low powered "bird" that uses a circular array of solar cells to power a device that makes bird-like sounds, and "Arcade Bells" that use a microprocessor and copper plated footless goblets to make resonating sounds similar to those in an arcade. The shape and density of an environment or container (such as the footless goblet or a foam padded room) has an effect on the vibrations made by a speaker.^[10]

Literature Review (Jessie Lee)[edit | edit source]

This is a review of literature related to weatherproofing and storing an exterior project containing electrical components.

Weatherproofing[edit | edit source]

The materials and weatherproofing required for the system is dependent on several factors, namely the climate of your location. Our project is for CCAT which is located in Arcata, CA in Humboldt County. Humboldt County has considerable precipitation and moderate temperatures, leading to regular humidity.^[11]

To protect the electrical components from precipitation and humidity, rain-tight or watertight boxes and covers should be used wherever possible. Rain-tight covers are only waterproof when the lid is closed, but watertight boxes contain a foam gasket for additional water protection. Wherever wiring will be exposed, at a minimum it should be in sheathing marked sunlight and corrosion resistant. For superior protection, run wires through a rigid conduit. To ensure the system is waterproof, complete a thorough inspection and caulk any seams or holes. For safety purposes, any outlet that could be exposed to water should be a ground-fault circuit interrupter (GFCI). However, it should be noted GFCIs are prone to tripping frequently in humid areas.^[12]

Storage[edit | edit source]

For convenience, as much of the speaker system as possible should be contained as a single unit, possibly on wheels to allow for mobility. Ideally, to promote sustainability, discarded materials will be reused to build the storage unit. Reused materials found onsite are even better as they do not require the fuel of transportation. If appropriate discarded materials cannot be found, materials made from recycled composites are another alternative. Either of these methods reduce the number of virgin materials used on the project. Depending on the building materials that are sourced, a nontoxic paint or stain will increase the expected life of the storage unit. If working near edible plants, emphasis should be placed on the use of nontoxic substances.^[13]

In addition to needing protection from weathering, wooden materials may also be susceptible to deterioration from insects such as termites. A variety of plant-based preservatives have proven effective against such insects and are safe for the environment. One study using neem oil, mahogany oil and shea butter oil found that all three alternatives were effective at termite deterrence compared to a control. However, neem oil was by far the most effective.^[14]

Literature Review (Annabel Mittelstadt)[edit | edit source]

This is a review of the available literature pertinent to similar solar projects/products to a homebuilt solar stereo system. To build an effective solar powered sound system, it is helpful and perhaps necessary to consider components and processes used in different smaller scale solar projects and systems.

Home built solar systems[edit | edit source]

Solar energy is becoming more widely obtainable through developing technologies that make it simpler to harness and therefore more accessible to more people. There are many household accessories that take energy, a Bluetooth stereo system being one of them, therefore it can be beneficial to learn to convert such things to be powered by solar on your own.

DIY (do it yourself) projects have become very widespread as people are increasingly trying to downsize, find more cost efficient alternatives, and become more self-sufficient and sustainable. This is the case with solar powered homes and objects as well. Micheal Boxwell's book is a helpful source for understanding the different aspects one should know when approaching a photovoltaic project in your own home. Having an understanding of photovoltaics can be very practical and cost affective for situations that require electricity that may be more remote, or need the ability to be mobile, or reliable--all of which are aspects related to our solar stereo project.^[15] Eric Smith's book on DIY solar offers insight on building other small scale solar projects such as solar ovens, solar water heaters, and a solar lumber kiln^[16]As solar power is becoming more simple to install and less costly, books such as this one, which cater to at-home projects and beginners, are helpful sources to consult for small scale solar projects such.

Examples of Bluetooth and/or solar speaker systems[edit | edit source]

These are a few examples of homebuilt speaker systems that incorporate Bluetooth and/or solar.

Example 1[edit | edit source]

This source goes through the process of building a Bluetooth speaker at home for around 35$.^[17]

https://medium.com/@kthornbloom/how-to-build-a-bluetooth-speaker-b145dd7475af

Example 2[edit | edit source]

Solar powered Bluetooth speaker system homebuilt^[18]

https://www.youtube.com/watch?v=HRUtRLCktcY

Example 3[edit | edit source]

Home built solar sound system^[19]:

suggested materials required for this solar speaker project:

• - 5v amplifier
• - USB power bank (as high capacity as you can find)
• - 2 double on/on rocker switches
• - Usb female panel mount port
• - Solar panels (mine are 13 - 15 cm/ 5V 500mA)
• - USB power meter (optional)
• - 2 regular rocker switches
• - 3,5 mm headphone jack
• - 3,5 mm female jack panel mount
• - DC power jack
• - USB bluetooth audio reciever
• - 2 speakers
• - A transistor or mosfet and the required resistor
• - USB car charger
• - 5V led strip

https://www.instructables.com/member/siemenwauters/

Literature Review (Kit Standfield)[edit | edit source]

This is a review of the literature relevant to working with solar energy and electronics in general.

Working With and Promoting Solar Energy Technology[edit | edit source]

Working with new technology can be difficult and fearful to work with at first. But within this reading, this helps educate about the basics of working with solar technology, educating others how to operate it and to promote and advertise the prototype you are working on and on a project you've been hired to work for.^[20]

Basics of Working With Electronics[edit | edit source]

Various types of electronic parts and circuits can only be assembled in certain order or setup to work. All forms of electronics can be found in multiple forms of devices and systems and take some time and knowledge to get correct. And within this reading is all the knowledge and information that is needed to understand basic electrical systems that can be applied to all types of technologies.^[21]

Harvesting Solar Energy in Low Harvest Systems[edit | edit source]

Low harvest systems are systems that do not collect and convert a lot of solar energy at one time, but still are able to use it. These systems can include outdoor timers, small lights and other small

electronics. Within this, it explains the conversions needed for small, low capture systems and solar panels in order for the systems to convert the energy into power.^[22]

References[edit | edit source]