Introduction
In this project I will be investigating how it is possible to use a temperature sensor to keep a greenhouse from changing temperature too much. This is intended to help plants live and grow in their optimum temperature. This will create a perfect temperature for the enzymes in the plants to work in, and therefore resulting in a maximum growth/production rate. This could be useful for gardeners who wish to grow plants as quickly as possible or maximise profits by maximising the product yield from their plants (for example; fruit, vegetables etc.) The aim is to set up a circuit that will automatically react to a change in temperature by allowing a heater (or similar device) to operate until the temperature is restored to the original, optimum temperature.
Preliminary Work
First of all, I will test a few sensors and analyse the results to decide on which on one is best for this particular experiment. The best sensor to use will be the one with the largest range of resistance over the temperature range in consideration, as this will mean more accuracy. This is because a greater range in resistance will result in a greater sensitivity; a greater difference in voltage per degree temperature change. There are 3 different sensors available to me, and I will simply address these as Sensor 1, Sensor 2 and Sensor 3. I need to measure the range of resistance that each sensor offers, from roughly 0¡ÆC to 100¡ÆC. However, the equipment available to me is very basic, and will only include a kettle, a supply of ice and a thermometer. Therefore, it will not be possible to obtain a temperature of 0¡ÆC or 100¡ÆC, as the temperature will never quite be 100¡ÆC as the water will cool down very quickly in room temperature, not allowing enough time to place the sensor in a sample of it. Also, there is likely to be a delay in the time the sensor will take to change its resistance, as it will need some time to adjust from room