• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Aim: Build a sensor circuit to test the proximity of an object using a light detector to detect light from a bulb reflected from an object.

Extracts from this document...

Introduction

Aim: 'Build a sensor circuit to test the proximity of an object using a light detector to detect light from a bulb reflected from an object.' In this experiment I am going to build a sensor circuit using an LDR, I will then calibrate the sensor and use my results to test and improve the sensor circuit. The LDR works by having a very high resistance when the light intensity is low, which does not allow current to flow through the potential divider circuit. When the light intensity increases significantly, the resistance reduces dramatically and current can flow through the circuit. The resistor within a circuit can be changed to make the circuit more sensitive. The first thing I had to do was to test two different sensors to see which one had better sensitivity. ...read more.

Middle

The LDR was fixed onto a block of wood so it was level with the bulb. A wooden block was also set between the bulb and LDR to stop light being detected directly from the bulb to the LDR. A wooden board was also used as the object that I would measure the proximity of. A one metre scale was measured out and the board was moved 0.05m for each measurement from 1m down to 0.15m. The Vout was recorded at each point on the scale. The experiment was carried out in a dark room. These are diagrams for the above description: Diagram 2 Diagram 3 My final calibration results are shown in table B: Distance/m Voltage Output/V 1.00 1.77 0.95 1.74 0.90 1.76 0.85 1.75 0.80 1.82 0.75 1.80 0.70 1.85 0.65 1.86 0.60 1.93 0.55 1.98 0.50 2.08 0.45 ...read more.

Conclusion

From my data I could see that the error varies with distance. This could be because of the LDR's limited sensitivity when light is reflected from longer lengths. This means that the percentage error increases with distance. To test this systematic error, I could calibrate the sensor for longer lengths, then test it and compare the percentage error to my first results. The effective range of my sensor is around 0.15m to 0.60m. Important properties of a sensor are good sensitivity resolution, rapid response time, small random and systematic errors. A sensors response time is the time it takes a sensor to respond to a change in it's input. Random error could be caused by a fluctuation in the input or from noise generated by the sensor, these errors are always present in experimental data. Systematic errors occur due to disturbing influences usually from the environment around the sensor and are not easily detected. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Systems and Control section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Systems and Control essays

  1. Aim: 'Build a sensor circuit to test the proximity of an object using a ...

    setting gave the maximum sensitivity as it had the biggest output to input difference. Next, I had to build my circuits. I used a potential divider circuit for the LDR and a simple circuit for the bulb: Diagram 1 For my final circuit design I used an 'orange power pack'

  2. Water level sensor

    I took down each voltage for corresponding water level. I took 3 set of reading so I could have an over all average latter on. Then I got two rulers to measure how high each ml was and tried to make it more accurate, I put one of them in the beaker and another one at outside which was used for measure.

  1. The aim of this investigation is to design, build and test a sensor.

    This means that more electrons are free to carry charge and therefore the voltage increases. In this way we can see how light intensity can affect the voltage. However, the amount of energy transferred to each electron by a single photon is dependent on the frequency of the light (multiplied by Planck's constant).

  2. Build a sensor that detects air flow using an incandescent lamp to detect the ...

    Overall I expect the circuit to work well, as the sir flow increases the voltage across the LED will also increase, thus getting a straight graph in the analysis. Safety: There is nothing too dangerous as I am not planning to use the soldering ion apart from the 12v voltage

  1. Use a sensor to make a measurement.

    The reading on both the voltmeter and the luxmeter are taken. The pointer on the variable resistor is now stepped up by a certain distance. The bulb decreases in illumination and once again, the values on the voltmeter and the luxmeter are taken.

  2. The aim of my project is to produce a working 'People Counter', which will ...

    Resistors must be placed in series with each diode to limit the current through each diode to a safe value. Early wristwatches used this type of display but they used so much current that the display was normally switched off, so to see the time you had to push a button.

  1. An electronics firm wishes to introduce a range burglar alarms. This coursework contains the ...

    Research into the 4098 chip From the guide to system alpha modules I have discovered that we already have a circuit for a double timer, which does exactly what I require. It has a positively triggered monostable timer linked directly to a negatively triggered monostable timer.

  2. Design and build an electrical toy for children aged 5 years and over.

    This means that it would have to be very aesthetically pleasing and soothing to the mind. An Electrical Gear Ratio Demonstrator This will be some sort of learning aid that children will also find fun to play with. It will basically be an assortment of gears linked to show you

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work