1. Design need. Tropical fish are expensive and they need to be kept at the right temperature or they will die, people need a temperature warning sensor. Users. Males/females, over the age of 14, because children under that age can’t be trusted to own and take care of a fish tank of there own. Also the product is an electrical appliance and has lots of small parts. Market. Would be sold in various fish shops around the country. People who own fish tanks and want their fish to be safe. Design Brief. Design and make an Electronic alarm that will detect if the temperature of the water in the fish tank is too high or too low. Dead

3. Alarms Where. Why. How. When Who What. Police Homeowners Shop owners Family Yourself House Owner of the alarm. To catch people. Warn people off. For fire To protect To help people Office Home Beach Shops Town. Safety. Wake you up Protect property. Lights Flashing Sound. Sirens Different noises. Robberies Rapes Attacks Crime

4. Alarm clock. Make a noise To wake you up In the bedroom Wake them up at a certain time in the morning it will not need maintenance because it runs off the mains For approximately 3/4 years It shows a digital clock display and is a basic round or rectangular shape. Weight and size aren’t really an issue, because they are generally quite small and compact. The outer shell of the alarm clock is made of plastic, generally an electrical insulator. It’s sustainable design, because it is made from plastic, which is recyclable. The product also last a long time, so it is environmentally friendly. Alarm Clock Smoke Alarm It’s a smoke alarm Make a loud noise Tell you that there is smoke in the house, maybe a fire. In the middle of the house so that there is the same distance around it in the house, so that it can detect smoke anywhere. The client will expect it to warn them if there is a fire in the house, so that they can feel safe and secure. The reliability of this product is very good, however, it runs on batteries so the user will need to test it every so often. Detectors are being sold with a lithium battery that can run for about 7 to 10 years, however, if you have an ordinary batteries then the detector will be expected to last about 3-4 years. The key aesthetics in this product are plain white plastic. Weight and size are really not an issue because they fit on your ceiling and are small and flat. The material used on the detector is a thermosetting plastic, so it won’t melt. It’s sustainable design, because it is made from plastic, which is recyclable. The product also last a long time, so it is environmentally friendly. House Alarm It’s a house alarm Makes a loud noise To let you and local authorities know that some one has broken into your house. There is a small computer system inside and there is a alarm box on the outside. They will expect it to work so they can feel that their house is safe and secure. The reliability of a house alarm is generally good because it runs oft the mains. It will be expected to last for a long time unless it needs upgrading The key aesthetics are that the box on the outside is fairly large and attracts attention to warn people off. But the alarm controls inside are fairly small and discreet. The reliability of a house alarm is generally good because it runs oft the mains. It will be expected to last for a long time unless it needs upgrading The key aesthetics are that the box on the outside is fairly large and attracts attention to warn people off. But the alarm controls inside are fairly small and discreet. The reliability of a house alarm is generally good because it runs oft the mains. It will be expected to last for a long time unless it needs upgrading The key aesthetics are that the box on the outside is fairly large and attracts attention to warn people off. But the alarm controls inside are fairly small and discreet.

5. I have found out that the users generally have expensive fish and are quite delicate. Also they said that they would like to know that their fish are save when away from the house. This meant that most of the people that were asked said that they needed a temperature sensing alarm. I think this product will be quite successful for people who care about their fish.

6. Specification FormIt will be a fish tank water temperature sensing alarm with LEDS Function It will sound a buzzer and flash LES when the temperature goes to high or too low PurposeTo keep the fish safe from dangerous water temperatures Performance Requirements It will be on top off the fish tank or mounted on the wall Client Requirement They will expect the alarm to sound if the water temperature goes too high or too low TimescaleFinished by Easter 2010 ReliabilityOnly the batteries to be changed every so often DurabilityFor 5 – 8 years AestheticsIt will be blue so it matches the colour to the sea, it is therefore relevant. Weight & SizeIt will be fairly small so it doesn’t use up to much space MaterialsPlastic so it is light weight Health & Safety No live components outside the case Manufacturing ProcessesUse simple materials to keep cost down and to make it easier to make. Batch Production it will have a range of different types of alarms and colours so people have more of a choice Environmental Issues it will be built using eco friendly materials

7. Jack Parkinson As the temperature falls the resistance goes up and voltage goes up. Thermistor Negative Temperature Coefficient As the temperature rises the resistance goes down and the voltage goes down.

8. As the temperature rises the output isn’t triggered, but when the temperature drops below 25°C the output is triggered, and the output is triggered. 741

9. I could use a buzzer as an output or an LED or both together LED Buzzer

11. Input thermistor ProcessOutput TransistorBuzzer This circuit will make the alarm come on when the temperature of the water gets to low, when the temperature is returned to normal the buzzing will stop. This is good because it is simple and effective, plus it returns to returns to normal when the temperature of the water is return to normal. The bad side of this design is that when the temperature of the water goes below, the buzzer sounds a little bit. Then when the water temperature is far too cold that’s when the buzzer is on full volume. We want full volume a soon as the water temperature is only below. thermistorComparatorBuzzer This circuit will make the alarm come on when the temperature of the water goes too low and will sound the buzzer The good thing about this circuit is that the buzzer will come on as soon as the temperature of the water is too low. The bad thing about this design is that the comparator only senses when the temperature goes to low not too high. thermistorcomparatorBuzzer thermistorcomparatorBuzzer This circuit will make the alarm come on when the temperature goes too low or too high. The good thing about this is that the buzzer comes on when the temperature is too high or too low The bad thing about this is that when the buzzer comes on you won’t know whether it is coming on for the temperature being too high or too low. My Alarm is only measuring temperature so I will only use a thermistor, because this is the only component that can be used to measure temperature. 1 2 3

12. thermistorcomparator Buzzer thermistorcomparator This circuit will make the alarm and the Led's light up when the temperature goes too high or too low. The red LED lights up when the temperature is too hot and the blue LED lights up when it is too cold. LED The good thing about this design is that when the Led lights up it signals whether it is too hot or too cold. This is even more helpful than just having a buzzer The bad thing about this circuit is that the buzzer sounds and the LED’s come on but hey go off after a certain amount of time. This means that if you are away from the alarm and you don’t hear it, when you arrive back you are completely oblivious to the fact that the temperature of the water has been above or below. thermistorcomparator Buzzer thermistorcomparator LED Latch This circuit will make the alarm and the Led's light up when the temperature goes too high or too low. The red LED lights up when the temperature is too hot and the blue LED lights up when it is too cold and then stays on forever The good thing about this circuit is that it tells you whether the temperature of the water has been too low or too high. If you have been out and you didn’t hear the alarm go off the LED’s are on to remind you that it has. The bad thing about this design is that there is no reset button so when the alarm is triggered then the LED’s will stay in for ever. thermistorcomparator Buzzer thermistorcomparator LED Latch Reset button 4 5 6 This circuit will make the alarm and the LED’s light up when the temperature is too low or too high then the buzzer will stay on until the temperature is returned to normal. The LED’s however will stay on until I return home and press the reset button. The good thing about this circuit is that when the alarm is triggered the LED’s will stay on a latch. Th e bad thing about this circuit is that the buzzer will always stay on unless the temperature returns to normal.

13. This is my only design because it is quite complex and took time to develop. After a lot of hard work it finally does everything a fish tank water temperature sensing warning alarm with LEDS should do. If the water temperature goes to high then the Red LED will shine and the buzzer will go off for 20 seconds. If the water temperature goes to low then the blue LED will shine and the buzzer will also go off for 20 secs. The LEDS will remain on until the push to break switch is triggered.

14. This is my circuit layout design. It consists of all the necessary components and has hop overs. The wires are copper so when I do the final design the wires cannot be hopped over.

15. This is the first circuit design. This is the bass model and gives a rough idea of what is to be expected. This is my second circuit design and I have included mounting holes and strain holes. I have also labelled some of the components. This is my Third and final design. It has all of the correct labels on it. I t has also been shrunk down a little more, now it will not use as much room on the PCB board. I have changed the parallel resistors for a variable resistor and an unmarked resistor. This is so I can fine tune the set temperature of the thermistor.

18. I made sure my acetate photo mask was the right way up on the UV light box, I exposed it for the correct amount of time and made sure the lid was down on the ultra violet light box. Next I put the PCB in the PCB developer, this etch’s away the plastic on the PCB that is not used. Next I Washed the PCB with water, and put it in the bubble etch tank which washes away the copper. The tracks are protected by the plastic layer, which the wire wool wipes away afterwards. Next I drilled out my PCB, I made sure that the holes were the correct size. I drilled 1mm for the components, 1.5 for the stain holes and 3.5 for the mounting holes. I made sure I had an apron on and goggles. Next I soldered in the components. I used pliers to bend the legs to make it look neat and slotted into the PCB nicely. When soldering I wore goggles and an Apron. After soldering in a component I wiped the end of the soldering iron on the sponge to clean the end.

20. Text We used labels to show where certain components and values We used colour to show whether it will show upon the circuit board or just so it shows up on the screen as a guide. Easy to edit I think it is easy to edit because you can move all of the components and wires around, and delete irrelevant things that you don’t need anymore. It is also easy to use. Components This show what components can be dropped on to the circuit board. The component sizes are already laid out so all we have to do is drop it in. Colour We used PCB designer so we could print straight out on to acetate. Print Alternatives One alternative is to draw straight onto

21. The only possibility was to use soldering this is cheap and effective, it involves the students more. It looks very good when done properly. The risks are that it is a hot iron and you have to concentrate on what you’re doing, you also have to have quite a long piece of solder so you don’t burn yourself. There are options if you go wrong tough because you can use the solder sucker to remove the solder that went wrong. We had a little practice at soldering so we knew the basics of it before we started.

22. Advantages of my Prototype It has LEDS and a Buzzer The LED’s stay on until the push to break switch is triggered by the person who has just noticed that their water temp was too high or too low. This means that even if they are out they will always know if the water temp has been off. The colour is appropriate because water can be blue and it matches. The thermistor dangles into the water and is attached to a long fly lead so the alarm itself isn’t too close to the water creating a hazard. Its got separate LEDs for hot water and cold water so you can easily tell the difference. Its got a push to break switch to reset the system once the alarm has gone off. Disadvantages of my Prototype There is no on and off switch so the battery will loose life much quicker. There is no flap on the bottom so you cannot replace the battery easily It’s too big so it looks to intrusive and obvious if it was mounted on the wall. I can see someone having to push the push to break switch a lot and it becoming annoying because it is quite sensitive, but this can be easily with the variable resistors. I think if I were to change my alarm I would try and make the circuit smaller because it made the case too big. Also I would have perhaps changed the colour to a black or grey because then it wouldn’t stand out as much. I Think my design isn’t one that anyone would have thought of because it isn’t a piece of technology that you especially need, however if you were to offer someone it i think they would want to buy it because it is actually quite an important factor in keeping tropical fish.