Accessories

The extra hardware that need to be connected to the basic interface box for doing any specific experiment is referred to as the accessory required for that particular experiment. They consist of sensor and control elements and signal processing circuitry. Several accessories have been already developed for different experiments. An accessory could be a simple RC circuit or something complex like a radiation detection and energy measurement circuit.


Standard Accessory Set (Photograph)
Included with the basic interface. Consists of several wires, RC circuit, LED, microphone etc. Diode IC characteristic, Charging and discharging of capacitor, digitization of sound etc. can be carried out using these.

Pendulum Oscillation Sensor (Photograph)
    Studying a pendulum requires measuring the angular displacement as a function of time. If we attach the pendulum to the axis of a DC motor, a small voltage will be induced on the connecting leads which is proportional to the instantaneous velocity of the pendulum. Since the oscillations are simple harmonic in nature, this is enough for getting the period of oscillations. 

Light Barrier (Photograph and Circuit)
    The light barrier is a U shaped structure with a photo-transistor and a Light Emitting Diode facing each other with a gap of 2 cm in between. There are three connections to the module, Ground, 5V supply and the signal output. The output of the module is generally LOW and goes high when the light emitted by the LED is prevented from reaching the photo-transistor. By connecting this to Phoenix Digital Input sockets one can measure time intervals by sensing the level transitions at the light barrier output. Applications include simple pendulum, rotation speed measurement (RPM meter) etc.

Coils, Ferrite and Magnet (Photograph)
   Electromagnetic induction can be studied using a solenoid and a magnet. This accessory consists of a 5000 turn coil and a small cylindrical magnet. To view a screen shot of the experiment click here.

Rod Pendulum (Photograph)
    The rod pendulum is 15 cm Aluminium piece with a knife edge attached to one end. It is easier to make this than a simple pendulum. The knife edges are supported on some stand and the pendulum is made to oscillate through the light barrier.

Piezo Transceiver Setup for velocity of sound (Photograph)
     The commercially avaiable 40 KHz piezo tranceivers are used for measuring the velocity of sound in air. The Transmitter and receiver piezo crystals are attached to a scale with some sliding arrangement using a magnet. The receiver output is amplified and used. To view a screen shot of this experiment click here.

Geiger-Muller Tube Circuit (Photograph)
   The GM counter sccessory generates the high voltage required to power the tube from the 5 volts pulse generated on the PWG socket. The pulses generated when radiation passes through the tube are counted by the CNTR input. The tube voltage is scaled and monitored by CH0.

Radiation Detection System (Photograph)   
  This accessory is capable of processing energy signals alpha, beta and gamma detectors. It mainly consists of a pre-amplifier, shaping amplifier, peak detection and some interacing logic circuits. A PN junction is used for Alpha detection. When a charged particle falls on the PN junction, electron-hole pairs are generated in the depletion region of the junction. These charges are collected by the highly sensitive pre-amplifier and then converted in to a gaussian shaped pulse by the shaping amplifier. The height of the pulse is proportional to the charge collected which in turn proportional to the energy of the incident particle. The height of the pulse is digitized by Phoenix and a histogram is made, with Energy on the X-axis and the number of particles with that energy on the Y-axis.

Analog Companion (Photograph)
  • +/- 12V / 100 mA regulated DC output
  • 3-0-3 Volts AC outputs
  • 4 amplifiers implemented using OP27 op-amp having an offset error of 30 microvolts.
  • Sine wave generator with  amplitude and frequency  control
  • Sine  wave generator  with  AM, FM  options

Programming Cable and LCD display (Photograph)
    Phoenix has a micro-controller inside the box. To program running on it has been developed using AVRGCC cross compiler. The output is transferred to the ATmega16 chip using a cable connected to the parallel port. While developing programs on the UC it is desirable to have a local display. Phoenix circuit has incorporated an LCD display and C library has been written to access it. This accessory is needed for those who want to program the UC and convert it into some stand alone device. Using the box from the PC does not require this cable.