PS 141 (CS) Electronics for
Computer Science Sophomores
  
 
sy2002-3 2nd sem : class projects to be presented on 14 mar 2003

t h calasanz

  1. Audio System
              --> audio-driven dancing lights
    2.
  2. PC-Based Real-Time Human Joints Movements
    3.
  3. PC Control of External Appliances
    4.
 

 

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1 - Audio-Driven Dancing Lights
 

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Ceres Parlade
Ryan Franco


Tentative Project Modules
  • Audio from Source - Audio signal will be taken from an audio source.

    •  
  • Condition Analog Signal - The sound will be amplified to an appropriate level.

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  • Modulate Lamp and/or Switch Lamp - The amplified voltage swings will provide modulated current flowing through a bulb to vary its intensity. At the same time, bulbs are also switched in order to provide a slightly different effect.

    •  

Learning Elements
  1. Using operational amplifiers for audio applications.
  2. Cascading stages of DC-coupled amplifiers to achieve high amplification.
  3. Controlled base bias current to achieve the desired current amplification.
  4. Achieving the switching effect through saturation biasing.
 

2 - Position Sensor
        (PC-Based Real-Time Human Joints Movements)

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Jericho Viejo
Jino Noel


Tentative Project Modules
  • Analog sensor for position - Translate joint angle into analog voltage.

    •  
  • Condition analog signal for digitizing - Feed this voltage into an analog amplifier so that the resulting analog voltage is of the level that is compatible with the "analog to digital converter" (ADC).

    •  

Learning Elements
  1. Behavior of voltage with respect to a voltage divider, where the node is determined by the position of the potentiometer wiper.
  2. Amplification characteristics of operational amplifiers.
  3. Operational amplifier configurations.
 

3 - Analog to Digital Converter
        (PC-Based Real-Time Human Joints Movements)

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Miguel Arguelles
Lerrizah Uy


Tentative Project Modules
  • Convert analog signal to digital data - Use common chips like ADC0804, or equivalent, to give an 8-bit code equivalent to the analog voltage. A more refined joint detection would use a 10-bit, 12-bit, 16-bit, or better, depending upon the resolution desired.

    •  
  • Latch output - It is desireable to latch this output in order that the computer can access it as the program requires. When latched, the ADC can process other analog signals from different channels.

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Learning Elements
  1. Analog to digital conversion (ADC) of the output of the position sensor.
  2. Interconnection techniques for circuits with several power supplies.
 

4 - Opto-Isolator Interface and Graphics Software
        (PC-Based Real-Time Human Joints Movements)

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Erik Troy Uy
Allen Uynicky


Tentative Project Modules
  • Circuits to test the PC ports - The primary objective of this module is to understand how the PC uses its ports. This understanding would make it an easy matter to write software for any external application, such as controls.

    •  
  • Opto-isolators - The PC ports are electrically coupled to its motherboard. It is of primary importance for the project to prevent external incompatible voltages from coming into the motherboard. For this reason, an opto-isolator is provided so that there is no direct electrical connection between an external device and the motherboard. Communication between the PC and the external device is through the modulation of light inside an opto-isolator device, such as a 4N25 integrated circuit.

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  • Read output into PC - In the design of the circuit, it is desireable to incorporate one bit that indicates that the ADC has completed digitizing so that the data read into the computer is current.

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  • Program interprets digitized data - Once inside the computer, the program could already be scaled in such a way that the range of voltage from V(0) to V(1) represents an angle traversed by the external human member.

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  • Program draws image for current position - An imaging program would rotate the image of the human member around the pivot, say elbow, to follow the actual position of the human member.

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  • Control of External Loads - Should time permit, the external hand position will also control the brightness of the light in "Project 6" and the on/off/blink control of "Project 5".

    •  

Learning Elements
  1. Transmission of data through an optical device.
  2. Interfacing hardware and software with a PC.
  3. Management of ports and of data.
  4. Translation of input data into graphics activity.
  5. Hardware control of devices in the outside world according to a set of algorithms.
 

5 - ON / OFF / BLINK
        (PC Control of Appliances)

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Trina Florencio
Cliff Lim


Tentative Project Modules
  • Receive "ON" Signal from PC - The PC sends a combination of bits to be interpreted as "ON", and the bulb is lighted.

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  • Receive "BLINK" Signal from PC - Another combination of bits is received from the PC to allow an external oscillator to blink the bulb through an appropriate gate.

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  • Receive "OFF" Signal from PC - The operation of the bulb is terminated when the PC sends an "OFF" signal.

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  • Implement PC Commands using Transistors - Transistors are used to switch the load to follow the PC command.

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Learning Elements
  1. Building and control of latches.
  2. Decoding of a combination of digital information to accomplish a task.
  3. Control of an oscillator to produce a desired effect.
 

5 - Lights Dimmer
        (PC Control of Appliances)

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Adrian Domingo
Noel Monte, Jr
Cha Gascon
Miggy Teotico
Perci Ko
Colynn de Guzman


Tentative Project Modules
  • Receive 8-bit Instruction from PC - PC sends this instruction through opto-isolators to assure complete electrical isolation between the PC and the outside world.

    •  
  • Convert Instruction into Voltage - The 8-bit instruction is sent to a "digital to analog converter" to convert this digital information into analog current and eventually voltage.

    •  
  • Provide Current Amplification - The voltage is sent to drive a bulb via current amplifiers. The current to the bulb is varied in order to change its brightness, or to put it off.

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Learning Elements
  1. Digital to analog conversion.
  2. Interpretation of analog signal for a light dimmer application.
  3. Appropriate transistor configurations for desired effects.
  4. Biasing of power transistors.