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

Moisture detector

Extracts from this document...


Electronics Coursework Aim: For my project I plan to build a moisture detector which can be used too see if the ground on the cricket crease is too moist or dry. It will measure the level of water in the ground and show the moisture level by lighting a different LED. So if it was a hot day with less water in the ground the moisture detector will only light up a green LED, then as the water in the ground increased another LED will light. Yellow for when the moisture level is in the middle of the scale and red for when the ground is too moist and so unsuitable to play any cricket. The first sub-system to consider is the input. I will put two contacts in my circuit so the processor can compare the resistance of the water. ...read more.


The diagram above is my preliminary investigation using LED's, by changing the 5K potentiometer the light will have more voltage or less voltage. The 100 ? resistor protects the LED, so not too much current is allowed through. By doing this preliminary investigation I knew that I could use LED's in my circuit, as I would have between 1.8V and 5V for them to run off. Secondly, I have also investigated the Op-Amp before. In a circuit with an Op-Amp (see diagram below) there are two resistors which hold the voltage for the non-inverting input (pin 3), these two stay the same. Then for the inverting input (pin 2) there is one resistor and a variable resistor, which can change the voltage allowed through it. As the voltage between the two resistors for the inverting input changes, from high to low then the output will change. ...read more.


Then at wetter levels more LED's will light, then when it is too wet the circuit will turn on three red LED's, warning the user. * Draw as little current as possible, less than 50mA. This will increase the amount of time the circuit can be run off a single battery. Block diagram of proposed system: The input will just be the two contacts that are put in the ground. Depending on the resistance of the water a signal is feed into the Op-Amp. Then the Op-Amp will send a high or low signal into an IC chip that will display the relevantly coloured LED. My circuit is restricted, as I could build a circuit that has an Op-Amp for each LED. But this would take too long and make fault finding extremely difficult. Only the cost is not restricting, as even if I built an Op-Amp for each it would still be very cheap to do so. Graham South Electronics - 1 - ...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. The paper discusses the issues associated with the risks assessed between the organizations bidding ...

    (business wire, 2005) It is key that the new Shang-wa/ Lester Electronics organization is financially viable in a large market to adequately be equipped to compete. Stakeholder Perspectives/Ethical Dilemmas There were numerous ethical dilemmas addressed in this scenario. The ones addressed directly in this paper are those that relate to net present value (NPV)

  2. Building a mass balance to measure small weights (0g-100g) using a rotary potentiometer

    Although the last digit on the digital multi-meter fluctuates this only means that the change in magnitude is been resolved. Linearity: My graph (output against mass) is a straight line graph(upward sloping) showing the relationship is proportional(as mass increases, the output increases).

  1. Bicycle Alarm Project

    By the addition of the above circuit this would add a further 2 two input NOR gates and the circuit would require a total of 6 two input OR gates and 1 three input OR gate which could be contained in 2 ICs.

  2. Design and Technology Project Design an Advertisement

    since I tended to get held up in certain areas of the manufacturing. Be made out of easily available, strong and easy to clean materials. All the materials my project was made out of were readily available in my school.

  1. A commercial company requires a dynamic advert for displaying their wares in a showroom/office ...

    In this chapter I will investigate the properties of these materials and decide what would be best for my project. Material Properties Acrylic Looks well, easily shaped, easily cut. MDF Can be painted easily, easily cut, durable Solid Wood Can be painted easily, easily cut, durable Metal Durable, strong These

  2. Electronics coursework.

    This however would not be suitable because my device has to be small and light, which is very hard to find metals in while plastics can be vacuum, formed or injection moulded into small shapes. Useful circuits to process the temperature change Potential divider This is a standard circuit that

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

    You will also need to connect all the load inputs, the carry in and the up/down input. http://www.doctronics.co.uk/4510.htm#BCD (pin out of CMOS 4510B) BCD to 7-segment decoder My next sub-system following the BCD counter is the 7-segment display decoder drive.

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

    It must sound for at least 4 minutes. It must allow the householders 20 seconds to de-activate the alarm before the alarm sounds. It must allow householders to leave the houses without triggering the alarm. It must be possible to reset the alarm at any time to stop it sounding.

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