Light Music
Schematic from /www.electroschematics.com
At the heart of this circuit is the UM66 IC, a sound generator. The IC is a CMOS LSI designed for using in door bell, telephone and toy application. When light shines on the LDR, the resistance drops and sends a signal to the T1 transistor. Power flows through the transistor to the UM66 musical integrated circuit, and a note will be amplified by transistor T2 and fed into the 8Ω speaker. The IC is preprogrammed to generate certain frequencies. When powered, the melody generator is reset and melody begins from the first note.
Part List
- Breadboard—Jameco
- Wire—Jameco
- 2 coin cell batteries—Jameco
- Coin Cell Battery Holder—Adafruit
- UM66T—eBay
- 8Ω Speaker—Jameco
- NPN Transistors—Jameco
- PNP Transistors—Jameco
- 10K Ω Resistor —Jameco
- 1 LDR—Jameco
- 1KΩ Resistor—Jameco
- 470 Ω Resistor—Jameco
- On/Off Switch—Jameco
- 1/2 Dual Mini Board with 213 Holes Protoboard—RadioShack
Instructions
Derived from /www.electroschematics.com
This version plays music when it is dark. The PNP transistor is the key to this circuit.
NPN
PNP
The PNP Transistor is normally "OFF" until a small output current and negative voltage at its Base ( B ) relative to its Emitter ( E ) turns it "ON" allowing a much large Emitter-Collector current to flow. PNP transistors conduct when Ve is much greater than Vc.
- Breadboard the circuit first to test it.
- Connect the power to power and gnd to gnd:
- Add the PNP transistor:
- Add the NPN transistor:
- Connect the base of the PNP transistor to gnd through a 10K resistor:
- Connect the base of the PNP transistor to power through an LDR:
- Connect the collector of the PNP transistor to power through a 1K resistor:
- Connect the emitter of the NPN transistor to gnd:
- Connect the collector of the NPN transistor to power through a speaker:
- Connect the base of the NPN transistor to a 470 Ω resistor:
- Connect the other lead of the 470 Ω resistor to the out pin of the UM66 chip:
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Connect pin 1 (gnd) of the UM66 to gnd:
- Connect pin 2 (Vcc) of the UM66 to the emitter of the PNP transistor:
- Add a poer supply:
- Connect the power to power and gnd to gnd:
- Freeform solder or use the protoboard to make your design more permanent
- Use a digital caliper to measure your components. Write down the dimensions.
- Think about how people play instruments. 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?
- 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 would make this fun to play?
- Ask what compromises need to be made when you design?
- Determine if the compromises are absolutely necessary?
- Determine if your 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.-
Research existing solutions. What aspects of the design appeal to you, why?
- Research how people hold things, and how they play instruments. 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 make music, when, where, and with whom?
- Make sketches. Draw a top view, a side view, an isometric view and include dimensions. Your drawings are your blueprints. Someone else should be able to use your drawings to build an identical model.
