Final Project...

For every class the projects had always been challenging and interesting in its self... Ever one of us in the class were required to build a circuit in a prototype for our final project.. Complete soldiered and fully functiong prototype was required for the project. We each had individual ideas over the project. For my submition, I made a prototype using a photo register. The pitch of the sound was processed by the litght sensitive registor. So every time I brought something to block the intensity of the light the pitch of the sound produced would differ. I could actually have different frequency come off with the circuit.
To give my project an interractive edge, I used a webcam to capture a minute of performance with the circuit. Then overlapped the sound , the previous recorded data to be the back track of my new performance. I countinued that for third time and came up with musical piece which was interactive to the self performance. Beside the sound intercation, looping video cincept was used to make the video interactive as well.

DIY Advice

- Always use a wet sponge to clean the solder from your soldering iron tip. Soldering tips degrade very quickly, especially if solder is left on them.
- Work in a well lit space where you can remain organized. DIY projects can get confusing and really disorganized, really fast.
- Do whatever you want. If you are doing it yourself, you should do whatever you want.
- Experiment. Breadboards are a great tool for experimenting with an unlimited amount of circuit combinations. Try anything; you never know what sound you will get.
- Acquire a de-soldering tool. Soldering can be pretty tough, especially when you are finalizing a circuit to a circuit board. If you drop a huge glob on your board, a de soldering tool will save the day.
- Lick your finger and touch things. Electronic things that aren’t plugged into wall outlets.
- Photo resistors and LEDs are best friends forever.
- Soldering guns are very hot. They will burn your flesh or melt your de soldering tool if you aren’t careful where you place them. Melting your stuff can be a bummer and filling your workspace with burning plastic fumes is just plain no good.

Tape Music

A microphone can be turned into a speaker and a speaker can be turned into a microphone. All you need to do to make the switch is switch things backwards. If an air microphone is wired to an audio output, the diaphragm will vibrate at the same frequency, making the signal audible, just like a speaker. If a speaker is wired backwards and its cone is vibrated, the frequency of that vibration will be turned into an electric signal can be played by a speaker. Electronic motors can also be turned into speakers. If the power input of the electronic motor is an audio signal, the electronic motor will turn on and off at the same frequency of that signal. This action effectively turns the motor into a speaker. Kristian Twombly demonstrated one of the possibilities that electronic motor speakers present by placing a small electronic motor on a 5 ft long span of packaging tape, suspended in the air between two points. The motor vibrated the tape and turned the entire span of tape into a very unique speaker. The motor was hooked up to a personal music player. The music could only be heard clearly if your ear was within a few inches of the tape. However, if you pressed your ear right up against the tape, the sound quality was much better. Also, the volume, tone, and timbre of the music is altered if you move your ear across the tape.

STUD STICKS

Look out Les Paul, guitar pick-ups are pretty easy to make and cheap too. In DIY audio we learned that an electric “guitar pickup” can be created by spooling copper wire around a sewing machine bobbin. A magnet is then placed in the inside of the bobbin. I placed my bobbin pickup on a wooden stick, just below a metal guitar string, strung up the length of the stick. When the guitar string vibrates, the copper wire and magnet create an electric signal which is sent down the length of the copper wire. I soldered the wire to an 1/8 in connector which I then plugged into a mini amplifier. The result was a surprisingly loud and rich timbered stick guitar! Stick guitars are a great fix if you need an electric guitar in a jiff. They can be used in performance, but are the most fun to just play and jam out. The total cost of one of these guitars is only a few dollars and if one string isn’t enough, it wouldn’t be too difficult to rig up five or six more!

DIY Audio and Beyond

DIY Audio taught me much more than just how to create microphones and electronic instruments with little or no cash. Before DIY audio, I had a very minimal understanding of electronics and wiring. That understanding was enhanced by DIY at “paradigm shift” levels. DIY taught me that most electronics are very simple at their most basic level. DIY also taught me skills like soldering and circuit construction. I learned how to make circuits that can be used for electronic sound, lighting, video, or just about anything electronic. I also learned how to repair or modify my own battery powered electronics. This class gave me skills that will save me large sums of money in the long run. This class also exposed me to an entire new world of artistic possibilities. The materials for DIY audio projects are cheap and easy to come by and their possibilities are limitless.

Final Project

The circuit I mentioned in my last post used a bcm14093 nan gate chip. I used this circuit to create the electronic instrument for my DIY final project. The resistance on the first oscillator is controlled by a 1 megahertz potentiometer and has a .1 uf capacitor. The second oscillator is controlled by a photo resister and has a 35 uf capacitor. The third and final oscillator is controlled by a 10 k potentiometer and a .1 uf capacitor. From the final oscillator are an audio out and then a 100k resistor and red LED. The LED lights up whenever audio is being produced. The two potentiometers are mounted on top a small black box, about the size of a tin can. The circuit is mounted on the long side of the box. The photo resistor is mounted on the left side. The 9 v battery is mounted inside of the box. The LED light is mounted on the top of the box, between the potentiometers. The instrument also has a large power switch mounted on its right side. When the switch is activated, a green LED inside of the switch lights up. The instrument can be played by altering the potentiometers as well as varying the amount of light exposed to the photo resistor. The potentiometers control the pitch of the sound and the photo resister controls the tone. The potentiometers can be controlled while leaving a finger or two free to control the photo resistor. I am very pleased with this instrument. The sounds it produces are awesome. They sound pretty good when played out of a mini amplifier and sound amazing out of a large amplifier. I have already begun recorded music with this awesome instrument.

Solder Practice

The first time I attempted to solder together a circuit was a complete disaster. All of the circuits I had created up to this point had been done on bread boards which do not require soldering. The reason for my failure was that I assumed circuit boards are set up in the same fashion as most breadboards. This is not true. It seems that circuit boards require close examination in order to determine how to set up your circuit. I had made the mistake of setting up my circuit on the circuit board in the exact same way I had set it up on the bread board. I had spent about six hours carefully soldering and de-soldering before I realized that my circuit was completely useless. On the bright side of things, the experience made me much better at soldering circuits. Re-doing the entire circuit correctly, took only about three hours. I also learned how to adapt my circuits to the interesting and sometimes confusing designs of circuit boards.

Bubbletron 4000

The Bubbletron 4000 is a giant, interactive, inflatable instrument/sculpture and was created by myself and Kirissa Grams. The first step to creating the Bubbletron was to tape many large sheets of clear plastic together into a large dome-like sphere. This sphere was about 8 ft wide on all sides and 12 ft tall when inflated. The “bubble” was inflated by connecting a large floor fan to the inside of the sphere with an 8 ft long tube made out of the same plastic material used for the “bubble”. We also created a hatch-like door on the side of the bubble so that we could get inside of the bubble once it was inflated. We then attached two different contact microphones to opposite walls inside of the bubble. These contact microphones were taken from the Kawasaki Drum Kit mentioned in an earlier blog. We soldered ¼ inch female jacks to the contact mics and then connected the microphones to multiple audio effect processors housed inside of the bubble. We also taped a contact microphone to the end of the inflation input tube. As air flowed into the bubble, the input tube flailed and waved around. The sound of the waving tube was also sent to an effects processor. All of the contact mics were amplified by a large amplifier and speakers housed inside of the bubble. The waving tube created a constantly changing sound that was very similar to the sound of thunder. The contact microphones placed on the inside walls of the bubble created very interesting sounds when the bubble was touched by someone on the outside. This sound changed depending on where the bubble was touched. The bubble could also be played by firing a “super soaker” at the sides of the bubble. All of the electronic equipment was protected from the water by the bubble walls. The bubble was set up outside on the St. Cloud State University campus and was up for about four hours. During this time, many different people interacted with the bubble and created many different unique sounds. One individual discovered that very dramatic squeaking sounds could be created by pushing their fingers hard across the plastic. The next time we set up the Bubbletron, it will have more contact mics and therefore, more potential sounds. We will also set it up earlier in the day when there is more foot traffic in the area.

4 for $4

The other day I visited a thrift store and picked up some old electronic toys. One of these toys was a Kawasaki Electronic Drum Set. The drum set is about the size of a shoe box, has 4 different drum pads and only cost $4. I dismantled the drum set and found that there was a contact microphone glued to the backside of each of the drum pads. When the drum pads were impacted, the contact mics created a signal which triggered a sample of a drum sound. The signal sent by the contact microphones is actually the sound of the impact on the drum pad, however, this signal was used by the toy to trigger a pre made drum sound. The chip inside of the toy also stored samples of music which could be triggered by buttons on the surface of the toy. The tempo and volume of the music could be controlled by two fader switches. While tinkering with the toy, I found that I could also control the tempo of the music by licking my finger and pressing it to different areas of the chip. The tempo change was much more radical and unpredictable with this method. This method also caused the audio to suddenly cut out. Flipping the power switch off and then back on again fixed this problem, but had to be done every time the audio cut out. I decided to disconnect the contact microphones and drum pads in order to use them for a future project.

Deep Contact

Air microphones are not the only way to amplify real world sounds. In DIY Audio, we also made contact microphones. Contact microphones are placed in direct contact with an object then amplify the vibrations of that object. We made our contact microphones by opening a piezo buzzer and removing the copper and quartz plate inside. We then soldered the two wires coming from the copper plate to an 1/8th inch male connector. The copper plate is glued to a very thin piece of quartz. When quartz is compressed, it creates a very small electronic signal. When the copper plate is pressed against a surface, vibrations from that surface compress the quartz and create a signal representative of the surface vibrations. This signal can then be amplified. When we plugged the copper/quartz plate (contact mic) into our mini amplifiers we were able to create all kinds of interesting sounds. Contact mics can be used to amplify heart beats. They can also be used to turn ordinary objects into musical instruments. Contact mics are best used for percussive sounds. These microphones can also be used underwater which is one of their biggest advantages over air microphones.

Air Microphones

In DIY audio we made air microphones by soldering a 9 volt battery connector to a resistor, capacitor, and two female 1/8th inch connectors. We connected the microphone piece to one of the female connectors and then connected our miniature amplifiers to the other. The air microphone creates an electrical signal when the small diaphragm in the microphone piece is moved back and forth. These movements are created by the vibrations in the air otherwise known as sound. Air vibrations are known as compressions and rarefactions. The nine volt battery, resistor, and capacitor amplified the signal sent by the air microphone. This microphone was surprisingly effective and inexpensive. These microphones are easy to make and are also very compact. It would be easy to hide these microphones in a space for an installation or performance.

The Final Failure

Advice to future DIYers: Don't drink a pot of coffee before you begin soldering your final project together. I usually pride myself on my soldering skills, but I'm usually not shaking due to copious caffeine consumption. Truthfully, I never figured out what went wrong with my final project. It was basically the circuit I outlined below (see "Recipe for my favorite oscillator") but I think something went wrong with the amplification area of the circuit. I thought it might be some problem with solder dots touching, but as I tried to clean it up, I made the connections progressively worse and eventually connected 5 pins of my 14093 to each other with a big blob of solder. After scraping the connections clear with a knife my circuit buzzes quietly; a pale shadow of its former self. I'll try to salvage it sometime, I don't like the idea of wasting such a wonderful chip.

Anyway, it's been an enlightening journey in DIY class. I learned a lot about electricity and sound. I got to listen to my hair. I will forever treasure my radio-shack mini-amp and the assortment of tiny electrical components which currently litter my carpet. I still think the class needs more enameled copper coils though. Many thanks to Dr. Twombly and my classmates. Have a safe and productive summer everyone!

Amp Chip 386N

Tiny and useful. Cut out the middleman! This circuit should be pushed back earlier in the semester. Once we built it I was able to apply my chips to the happy task of oscillating all the random speakers that are scattered around my room. No more restrictive mini-amp. Better yet, you can build the 200-gain variation and listen to the distortion as your speaker attempts to cope with the ridiculous amount of power. And it uses one less battery than the typical mini-amp setup. This was a vital piece of my final project (and sadly the source of its failure) but after I dig it out of the circuit board I'm sure I'll be using it again.

I assume if you made a fancy little case for a circuit like this you could undercut radio-shack by selling the things for 10 bucks on ebay.

That Amplitude Follower / Gate Thingy

By far the most complicated circuit we built in class. I understand the uses it might have but in my opinion the returns don't warrant the effort. Other than making mp3 players sputter with oscillator controlled volume it doesn't seem to serve much purpose. I mean, the lights are pretty and all, but I want my circuits to generate sounds not follow them. I suppose if you were building a stereo it would be a useful indicator of volume, but I don't frequently build stereos. And what happened to our class playtime? That's the best part! Another note to Twombly: Don't cut out playtime. Also, get some of those frequency divider chips next time around, simpler and way cooler than amp tracking.


Hmmm... now that I think about it though, it might be interesting to modulate the amplitude of one oscillator with another oscillator. Perhaps a summer project?

Guitar Pickups

Our Guitar Pickups combine two of my favorite things: Powerful magnets, and copper coils. I don't quite understand how a magnet that is glued into the center of the spool can vibrate enough to induce a current. But it does, and I guess that's all I really need to know. My guitar was a soprano as I could only find a two foot stick. Fun but tragically limited to the fundamental and harmonics by the single string setup. Frets would be useful. I thought it might be fun to pair a series of pickups to a few strings, but I found out someone beat me to it already. I briefly experimented with trying to pickup signals from other things, but results were similar to a poorly constructed telephone pickup.

I'm much more interested in building the inverse of a pickup: a speaker. Note to Twombly: consider adding a speaker assembly day, there was a disappointing lack of copper coils this semester. Better yet, build the amp circuit and a speaker early on and we can use homemade speakers on the other projects.