Light Sensitive Alarm
The Challenge
How do you stop people from snacking or make people aware of how much they are snacking?
The circuit for the fridge alarm, originally created by
Forrest M. Mims III is a light-activated switch that activates a piezo tone generator. When the cadmium sulfide photoresistor (photocell) is surrounded by darkness, its resistance is very high and the NPN switching transistor is off. When light strikes the surface of the photocell, its resistance falls significantly which causes the voltage divider to apply sufficient bias to the transistor's base which allows the current to flow through it to the piezoelectric buzzer.
Instructions
Considerations
Maybe you want a light instead of a sound?
- Breadboard the circuit first to test it.
- Use a digital caliper to measure your components. Write down the dimensions.
- Freeform solder or use the protoboard to make your design more permanent
- Think about how people snack. Follow the steps of the design process, then design the housing that reflects your thought process.
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? Do you want to make the misstep private or public?
- 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?
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 notebook to keep track 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. What aspects of the design appeal to you, why?
- Research what people snack on and when. Make sure you know more about this problem than what is provided here on this web page.
- What are your constraints? Make a list.
- Observe how people snack, when where, and with whom. How often do they open a refrigerator or a cabinet? Also observe habits and how habits can be formed. What makes people stick to a routine, be that a morning or exercise routine? How do parents help children develop good habits? Why do people overeat? Can humor help, a gentle reminder, an alarm?
- Make sketches. See Examples
