The Circuit
Parts
- Hex Schmitt Triger (74C14)—Jameco
- LED
- 9V battery connector—Jameco
- 9V battery
- 2.2uF capacitor
- Wire—Electronix Express
- 1 MΩ potentiometer
- 1K resistor
- A battery-powered mini amplifier or a Piezo-electric disk
- 2 1/8" stereo miniplug connector—Cable wholesale
- 2 1/8" stereo miniplug connector
- Photo resistor
Instructions
Schematic
Things to keep in mind
If your circuit doesn't work:
- Check your connections
- If the chip gets hot, disconnect the battery immediately.
Make sure the chip is in the board the right way - Too small a capacitor or resistor will cause the circuit to oscillate at a frequency too high to hear.
- Check that the chip's pins have not been folded over.
- Make sure GND and power are connected correctly.
Before you start breadboarding
- Solder wires to the center and right leads of your potentiometer.
Hex Schmidtt Trigger IC
Hex Schmidtt Trigger
- Connect power to power and ground to ground
- Place chip in breadboard and connect pin 7 to GND and pin 14 to power
- Place a 2.2µF capacitor between pin 1 and GND.
- Connect pin 1 to 2 with a variable resistor (potentiometer,a LDR, coins).
Connect pin 2 to the anode of an LED through a 1K resistor.- Connect the cathode of the LED to GND.
- Test the circuit.
- Connect the circuit to an amp to listen to the oscillator.
- Connect a second LED in parallel
- Remove the first LED and arrange it and an LDR on tape like this:
- Wrap the components in electrical tape:
- Grab an audio source and connect one of the leads of the ldr to the red wire of the input. Connect the other lead the the red wire of an output connected to the mini amp.
- Connect the GND lead of the input source to GND through a 1K resistor.
- Connect the GND lead of the output audio to GND.
- If you are not going to build an audio oscillator document your project at this point. Otherwise follow the design process:
- Use a digital caliper to measure your components. Write down the dimensions.
- Research how people play with knobs and audio oscillators. Follow the steps of the design process, then design the housing that reflects your research.
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Basic steps of the Design Process
The Design Process requires- Describe the general situation or problem you are trying to solve. Instead of asking what do you want to design? ask why do you want to design that? and what problem and or need will your design ultimately be solving?
- Identify your target audience, the group that will benefit from your project. Is the target population an individual, a group, a specific community, or a larger, identifiable population? Is the target population from a specific location (country, region, town), demographic (age or gender), or other identifying characteristics (health condition or employment)? Think about how is your target population connected?
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Identify the requirements and constraints. A requirement is a need or a necessity; it's what a particular product or service should do. A constraint is a restriction on the degree of freedom you have in providing a solution to a need or problem.
- Ask what are the disadvantages of the present solution to the problem?
- Ask what compromises have been made in the present solution?
- Determine if the compromises are necessary?
- Determine if the solution can be improved?
- By taking a new approach.
- By making the design more accurate.
- By making the design more safe.
- By making the design more convenient.
- By making the design easier to maintain.
- By making the design cheaper to produce.
- By making the design more attractive.
- Determine if you can reduce the costs by eliminating parts, using different materials, changing the way the product is manufactured?
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In a nutshell
- Design Step 1: Identify the Need
- Design Step 2: Research the Problem
- Design Step 3: Brainstorm Possible Solutions
- Design Step 4: Engineering Analysis-select the most promising solution
- Design Step 5: Construct a Prototype
- Design Step 6: Evaluate/Manufacture a Final Product-Reiterate
Getting Started
Keep a record of your questions and answers. The design process will help inform your choices and should be an integral part of your creative process.
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Research existing solutions to musical instruments. What aspects of their designs appeal to you, why?
- Research how music is played. Make sure you know about knobs and fingering notes than what is provided here on this web page.
- What are your constraints? Make a list.
- Observe how people use audio oscillators and how they hold objects. Will your bended circuit rest on a table, be held in a hand or fixed to a surface?
- Make sketches. See Examples
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Research existing solutions to musical instruments. What aspects of their designs appeal to you, why?
- Describe the general situation or problem you are trying to solve. Instead of asking what do you want to design? ask why do you want to design that? and what problem and or need will your design ultimately be solving?
- Use a digital caliper to measure your components. Write down the dimensions.
