Evaluation (Relating to brief, specs and constraints)

Evaluation (Relating to brief, specs and constraints)

At the beginning of the DTM course, Dr Tony House had made up a brief containing specifications and constraints that we had to follow. The brief stated that the solar garden light had to be resistant to the harsh outdoor conditions especially since the light was going to be placed next to the beach. The light would have to endure harsh winds, rain and the corrosive salt spray. The light had to be camouflage amongst the poacita grass and it shouldn’t cost any more than $30.

My light’s measurements are 160mm high and 150mm in diameter so it can be easily camouflaged amongst the poacita. My light is made of aluminium and is in the shape of a cylinder. My light shouldn’t get blown over in the wind if it was to be planted in the ground firmly. If the light was to blow over, it wouldn’t matter that much as the light is durable and strong. However, Dr Tony House would have to waste time making it stand back up again. A good thing with aluminium is that it is cheap and it is easy to work with since it is malleable and soft. Another benefit with aluminium is that it won’t corrode and it will always stay nice and shiny unlike steel. My light has been sealed so rain and moisture can’t enter the inside of the box damaging the delicate electronic components of the circuit. An additional feature that I have found out recently is that my light is mostly resilient to a lightning storm as the aluminium acts as a conductive outer shell and the power surge is earthed through the ground so the circuit is not damaged. This prevents Dr Tony House having to buy another light when the current light gets struck by lightning.

My garden light has a very bright lightbulb inside so it will put out adequate lighting unlike LED’s. The only problem with the light I used is that Dr tony house will have to waste time changing the light every now and then as the light does not have much of a long life expectancy. This would not have been a problem if the CCFL had survived. The top part of my light is made mostly out of vacuum form plastic and acrylic. This is good because it has extremely high transparency to minimise waste light. These two plastics that I used are resistant to wind, rain, salt spray and being knocked around. I have also sealed up my light so it won’t leak resulting in a build up of condensation and damaging the internal electronic components.

My light has got a few problems with the circuit when the batteries go flat. Considering my circuit contains a relay, the light starts repeatedly flashing no and off for about 5 minutes. After that, the relay turns on and off extremely fast resulting in a rather loud humming sound. After a minute or so, the light will start making clunking noises slowly working down to a clicking noise. This is a very good indication that the batteries need to be charged up. A solid state relay would fix most of these problems.

Overall, my light has met most of the specs and it cost less than $30. The specs that it did not meet were things like not having a dimmer knob and on/off switch. My light has met all of the main specifications that Dr Tony House has stated in order for it to last.

Evaluation (design process)

11dtm final design evaluation                                     Jamie Stenhouse

 

I have put a lot of time and effort into my solar garden light to make it work and look good. I am happy with it but given the time, I could make it look a lot better and could have had a much better design. Throughout the year, I have encountered many problems and challenges to get it to work. My light design had to be changed a number of times due to it being too complicated and not having the time.

Our class went on a field trip to the Unknown Soldier, Waitangi Park and Civic Square. At those three places, we all studied and sketched the outdoor lights. We listed down things such as what they were made of, how they were mounted and what lighting effect they would have on the surroundings. This gave me an idea on what my light was going to look like. After that, we all did some research on the internet about different materials such as aluminum, brass, acrylic, etc.

Dr Tony House (our client) had a brief for us all to follow. He wanted a small, low maintenance outdoor solar garden light that was bright at night. He lived in the Coromandel (opposite the beach). Our light had to be made of non-corrosive materials so they wouldn’t corrode from the salt water. Also, our lights had to have a high light output, be self powered, turn on at night and off at day, be low maintenance and cost less than $30. The lights needed to light up Poacita grass at night and be camouflaged at day.

I started out with a very simple design that was drawn on paper of a box that had solar panels on the top and lights on the bottom, then I made some 2D drawings on a computer program called freehand. I had a simple box made of clear plastic with an aluminum bottom. From there on, I had thought that I could make something a lot better and I came up with the idea of having a cylinder shaped light with a LED cluster to illuminate the surroundings. I stuck with this design and had worked on it to make it better. Later on, I had a simple, effective design which I liked and knew that it was easy to build.

I made a cardboard mockup of my light and it looked quite big and bulky. From there on, further modifications were made. My light had two main parts. An aluminum cylinder at the bottom and a plastic cylinder at the top. The aluminum cylinder was where the circuit and batteries would be. I knew that the circuit wouldn’t take up that much space, so I halved the cylinder to make the light look better. The plastic cylinder at the top looked too small for the light I was wanting to use, so I made it a lot bigger. This way, there would be better light output. 

Most people were using transistor oscillator circuits to run little LED lights. In my opinion, they were extremely dim and not effective. So I planned on using a cold cathode fluorescent light (CCFL) as it had a lot of light output and was very effective. I had the light and the ballast (the circuit to create the voltage in order for the light to discharge) all ready but first, I started on my box.

The first thing I did was cut out a circle on the cam machine. This was going to be the very bottom of my light. Once I had done that, I cut a long strip of aluminum on the guillotine. I put this piece of aluminum through the rollers so it would take the shape of a cylinder. This was riveted so it held itself in place. Once I had done that, I made up some brackets using the guillotine and the metal bending machine. These held the bottom plate on so it wouldn’t fall off. I used screws instead of rivets so it could be taken apart in the future if any maintenance needed to be done on the circuit. Then I cut out another circle on the cam machine and made some more brackets up to hold the second circle. This was for the other side of the cylinder. That was the cylinder complete for the circuit to sit into.

I started working on the second cylinder. This one was made out of plastic. I got a piece of vacuum form plastic as it was flexible and completely transparent. I cut it to size using the band saw. Once it was cut to size, I bent it around, overlapped each of the ends, drilled holes in it and riveted it together so it would stick to the shape of a cylinder. I made up some brackets that were straight. I drilled holes in them and then riveted them to the top of the aluminum cylinder. The plastic cylinder would sit in the brackets and be riveted into place. Once I had done that, I drilled holes in the vacuum form plastic and then riveted it into place. One really stupid problem with this was, I realized that the plastic still had its protective layer on and I would have to peel it off when it had already been riveted into place. It could have been worse.

I had finished the box and now I had to make the circuit and set up the solar panels and light. Once I had completed the circuit, I tested it and found out that the ballast was pulling too much current for the transistors. The light would glow very dim and the transistors got far too hot. I fixed this problem by putting a relay where the output was and have the power come directly from the battery through the relay and into the ballast. This solved the problem and the light was working correctly and turning off when it was daylight. I then glued the circuit in place making sure that it would not short circuit on the aluminum. I drilled six holes in the top circle. Four of the holes were used for the solar panels. One hole for the light and the last for the LDR. I soldered wires to the four solar panels and glued them to the box. I then glued the light making sure it was in straight before the hot glue had set and then I glued the LDR in place. My light was all starting to come together. 

An attempt of making my solar panels sit more flush onto the box seemed like a big mistake when I had snapped my light in half. This was not good at all as time was running out and I couldn’t get replacement CCFL lights unless you order them in. also if i was to order a new one, i would have completly blown my budget as the light without the ballast would cost more then the whole solar garden light once complete. I had to change my light. That did not mean that I was going to use LED’s though. In my lunch time, I went to Jaycar and purchased a krypton light. This light still needed the relay but not the ballast. This was good as my circuit just got a whole lot less complicated. I removed the ballast and had the light wired directly to the relay. When I tested the circuit, I found out the krypton light had a higher light output and a nicer colour temperature then the CCFL (it wasn’t at all like the LED’s). I tested the circuit with a multimeter and everything was working great. The LDR was working and the solar panels charged up the batteries. I was very pleased with the light and the way it worked out.

I then cut out a top disc on the cam machine. This is to cover the top cylinder. I was originally going to use aluminum for it but for some reason, the cam machine hated me. It kept on jamming up, so I used transparent acrylic. This was good because it allowed more light to be dispersed. The first piece of plastic had snapped due to the drill. Too much pressure was applied so I had to cut another bit in the cam machine. The second bit of plastic didn’t snap in half as I drilled it with care. This consumed more time which wasn’t very good as I was seriously running out. I then made some brackets to hold the disc into place. I used self tapping screws instead of rivets because if the bulb blows, it can be easily changed by unscrewing the top. The light looks very good and its light output is very, very bright in comparison to the LED’s. It would have been a lot easier for me to use LED’s as they would be very hard to snap in half unlike the CCFL light. However, I have stated my opinion on LED’s. Anyway the bulb I used is a lot brighter.

Overall, I am very pleased with my light. It is very effective and has a great lighting effect. I had a great time designing and assembling the light although there were a few problems along the way. There are a couple things that I would change about the design and if I was to make another one, I would take my time and be more careful with the production of it. However, I am very happy with the progress I have made with it considering it is my first garden light.

 

Tool List

·         Guillotine

·         Cam machine (2mm milling bit)

·         computer

·         Rivet gun

·         Pliers

·         Wire strippers

·         Metal bending machine

·         Soldering iron

·         Solder wick

·         Drill press

·         Hand drill

·         2mm, 3mm, 5mm drill bits

·         Files

·         Band saw

·         Screwdrivers (Philips, flathead)

·         Silicon sealer

·         Hot glue

·         Scissors

·         Cardboard

·         Masking tape

·         Rollers

·         Vice 

Materials List

Casing:

·         1.5mm Acrylic

·         Vacuum form plastic (transparent)

·         Sheet aluminum (transparent)

·         Self tapping screws

·         Rivets

 

 

Circuit:

·         PCB boards

·         CCFL light

·         Krypton light

·         Relay

·         Transistors

·         Diode

·         Resistors

·         Transformer

·         Inductor

·         Capacitors

·         Solar Panels

·         Wires

·         Solder

dtm week 5 term 4 (the final week)

this is the final week. my light was nearly finished but i had all of this glue on the solar panel. i also came in on saturday. when i was taking the glue off to make the light look better, the light had unfortuanely snapped in two. this was not good as there wasnt a replacement light at jaycar. i decided to change my circuit and use a krypton bulb. this still was very bright and it had a better colour temperature. i really need to finish it though. all i have to do is glue the light into place, screw the bottom on and charge the light. i will be done by the end of today.

week 4 term 4

this week has been average. we are running out of time and i need to seriously finish my blog site or i will fail. i am nearly finished on my light. i have glued my circuit to the box. i have also glued the light in and it looks good. i have tested the light and in my opinion, the LDR is not sensitive enough but the light is really bright and that is a great thing

reflective practice

this is my reflective practice. it is about what i think of dtm.

week 3 term 4

this week has been full on and time is running out. i came on saturday and i cut out the top on the cam machine. the top was made of acrylic but a problem i had encountered was the rivet had cracked the plastic so i had to make another one. that sucked but i will screw the top into the box so it wont crack. im nearly finished and mow all i have to do is put my solar circuit into the box. i am happy with my light so far and i think i can completly finish it

term 4 week 2

this week has been a very busy week. i have done alot of practical as there is not much time and i really need to get this all done. i have made a top of my aluminium box and i have also made a
plastic cylinder for the light to shine through. this also protects the light. i need to rivit brackets on to hold on the plastic cylinder and then i need to make up some more brackets. once i have done that, i will need to put a top onto my light and them wire it up. this week has been a good week and im pretty close to finishing.

term4 week 1

this week i have to focus on getting my blogger finished before week 4. my goal is to completely get my blog finished and pass with excellence. i also want to get my garden light finished. ill need to blog from home.

holidays

in the holidays, i had attended a course through school for help with NCEA. i thought it was quite boring but it would help later on in the NCEA exam. the second week was quite quiet though. i cleaned up my workshop and repaired lots of stuff. i cut down all of these trees and got $10 so i went to cash converters and got 2 uhf radios. i got some batteries for them. i also went sailing and i installed this heater in my friends boatshed. the heater is good because if you are wet from sailing then you turn it on and it is very warm. i had a fun holiday.

week 10 term 3

this week was really bad because we had a reliever who made us to do oragamy. i would rather do practical. i have not done much practical work lately. i do need to catch up on making up some top brackets for my base of the light. once i have done that, i need to cut some acrylic and bend it into a circle for the light to come out.

week 9 term 3

This week has been an exiting week as i have got back into doing my dtm work. i have cut of the tabs off the bottom of the base as i have chosen to use rivits and brackets to hold the bottom of the base in. i have made up 4 brackets out of aluminium and these are going to be riveted onto my cylinder. i have also cut my cylinderin half so it is not as high. The light is not going to be using the big lead acid battery so it looked slightly rediculous with it being so high. i am now going to use 4 double a rechargable batteries.

week 8 term 3

This week has been exam week so it has been a real problem for me as i have not been able to do any of the practical things that i like i this course. this is the main problem i have encountered

week 7 term 3

this week i have cut my slab of aluminium in half for my light as it was too ig and he light would look quite ugly. i need to do a bit of work on the body of my light as it looks a bit shabby. i have made alot of progress though

my bottom plate for my light

this is the bottom plate that i am going to use for the light that i am going to make. it will soon be cut out on the cam machine.

materials justification

i have chosen to make my light out of aluminum and acrylic plastic. aluminium is a cheap non-corrosive metal which is malleuable and can be easily cut. it is good because its not corrosive so it cannot rust or corrode. the aluminium is going to be used for the body of the light. i am using transperant clear acrylic plastic for the light output. i am using this because it is very easy to work with and it can be very easily cut in the cam machine. this plastic has a high level of transperancy and can come in a range of different colours. it is also cheap

week 3 term 3

this week, i have started my cardboard mock-up of my solar light. this is going to be a 1:1 scale mock-up of my solar garden light. i also have the problem still yet to resolve with my transistor circuit. i will continue doing my mock-up first though to get that out of the way. my goal is to get my mock-up finished at the end of my double practical on this Friday.

my new cold cathode lamp

i have made a change from white led's to a white cold cathode light. i have got a small cold cathode light that has its own 6v ballast. this light is alot brighter and since the anode and cathode dont get hot, it lasts alot longer then a hot cathode lamp. i have tested the light and it works without any problems. unfortunatly, when i use it with my transistor circuit, the light will not ignite as there is insufficant power going into the ballast. this is not good as i cant use the origional circuit that ran the led's. the problem is with the transistors as there is too much currant being pulled. i need another circuit that has the same features as the origional circuit yet it can run the ballast. this is a problem.

moification to my final design

my final design uses leds to make the lamp light up but i am thinking about using a Cold Cathode Fluorescent Lamp (CCFL). this is a thin glass tube with a small amount of mercury vapor. the inner side of the glass is lined with phosphors with added impurities. this is designed to make a white light and not an ultraviolet light which is harmful to the skin and eyes. unlike hot cathode fluroescent lamps that uses heat to ignite the mercury, cold cathode lights uses a discharge to ignite the mercury and make a plasma. these lights require a ballast to regulate the voltage and to start the light up. i am going to use this light inside my final design. i have a 6v ballast, a 6v lead-acid battery and a 6v 20w solar panel. i am using this light instead of a white led as it is alot brighter.this light is more suited to a lead-acid battery. it does not generate much heat and it has an alround light output unlike a led. this more on CCFL here.

week 9 term 2

this week we have been handed out another checklist for the blogs to complete. since i have finished my prototype, i am helping other people to get there ones complete

dtm week 9 term 2

this week, i have done a lot of paperwork for my course. i have caught up on a lot of blogging for my course over the year. my blog will be updated over the holiday break.

week 8 term 2

i have pretty much finished my prototype light. i have to seal up the solar panel and then wait a day for the silicon sealant to dry. it also gives the light a nice finish and i am happy with the way it has turned out

term 2 week 8

this term i have finished making and modifying my prototype, my final design and using some solid works. my next thing that i want to complete is the solidworks version of my freehand final design. next term, i want to get my big solar garden light underway

final design v4

this is my last final design that i am going to make on freehand. this design is the design that i am going to make. soon, i will start making it in solidworks and then i will be able to have a look at a computer generated version of the light in 3D. i can flip the light around. i will also be able to view the light in different materials and on different surfaces.

week 7 term 2

this week, i have modified my circuit for the prototype and im helpimg some other people do the same. i have also had another attempt at using a program called solidworks and i dont like it that much

my final design v3

this is my third final design. i have used a circular shape this time . it is alot different from my second final design that i had made. this design uses 4 leds and is alot taller then my second design. it looks more like a lantern lind of thing, but more modifications could still come

prototype evaluation

I have completed making a small self powered light. It is made of aluminum and it has got a small solar panel and 2 white led’s. The light is a box shape and it was cut out inside the cam machine. The cam machine is a computer aided machine that cuts out most material in the form of a sheet. The cam machine cut out 2 parts to the box. One part of in the shape of a plus and the other part was the bottom of the box. With the first part that’s shaped like a plus, I had to drill 4 holes in the top using a drill press. Two holes are placed on the outside for the 2 white led’s to come through, and two holes are placed in the center of the top panel for the solar panels wires. Once I have drilled the holes out, I had to bend the sides of the box up. The box was bent on a metal bender. A metal bender can bend sheet metal. I folded up 2 sides to 90°. One problem that I encountered was folding the other 2 sides upwards. I could only bend them up to about 45°. To resolve this problem, I had to bend the metal by hand. Once the box was bent, I then needed to make up 4 brackets to hold the sides of the box a lot stronger. I got some scrap aluminum and scribed out my brackets. I cut them out in the metal guilitine and marked where I need to drill the holes for the rivets to go through. Once I marked where the holes were going to go, I drilled the holes out. Another problem I came across was that I had to drill the holes in another place of the bracket on the other side to make sure that when the brackets are riveted in, they won’t clash with each other. Once I had drilled the holes in the bracket, I then had to bend them 90°. After I had bended my 4 brackets, they were finished. So the next step was to drill holes in the box using the bracket itself as a template. 16 holes were drilled in total using a cordless drill. Then I riveted the brackets to the box using 3.2milimeter rivets. The top and sides of the box were complete. I was now up to the stage where I have to bend and drill the bottom plate for the box. The bottom plate was in the shape of a square with 4 small tabs coming out from each side. The first job was to scribe on the four tabs where the drill holes are going to be. Once this was complete, I then had to drill out the holes and bend the four tabs upwards. The tabs fitted around the side of the box. Another problem was that the tabs were not long enough to fit on the outside of the box, so it had to be forced to fit using a wooden hammer. After this was complete, the back plate fitted tightly. After that, I had to use the back plate as a template to drill holes into the box where the holes in the tabs were. The next step was to put screws through the holes that I had just drilled out. I had finished making the box, so the next thing to do was to modify the circuit. I had to desolder a warehouse circuit out of another solar garden lamp I had pulled apart previously. I removed the battery snap, the solar panel and the white led. I soldered on 2 new white led’s in parallel and then heat shrinked the terminals and soldered a new battery snap and new wires for the solar panel. Once I had done this, I then glued the circuit to the aluminum box along with the battery snap. Then, I pushed the led’s through the 2 holes in the box and glued them in place. Then I screwed the back plate on to the box. I also pushed the 2 wires for the solar panel up through the 2 holes in the centre of the box. Once this was complete, I soldered the solar panel. Then I glued the solar panel to the box leaving about 2 millimeters between the solar panel and the box to prevent a short circuit. The final step was to get some silicon sealant and put it around the solar panel to seal it up. My prototype was complete. I really like the size of the lamp and I like the industrial look about it. And I like the material chosen and also I am very happy because the light works. The one thing that I could do better next time is have the back plate cut bigger by 1 millimeter so that it can fit onto the box a lot more smoothly. Also I would like to have a three volt solar panel and 2 batteries in series so I can get the voltage of the circuit up to 3 volts for a brighter light output.

my first prototype

so far, i have completed my first prototype and it goes. i have tested the ciecuit and glued the circuit in place. once i had done that, i soldered on the solar panel through the box and then used a silicon sealant to glue it in place.

week 6 term 2

this week, we have done more pratical on our prototype lights. friday will be good as we will be able to do practical work for 2 hours. i will get alot done. 6/10/2008

my first prototype

i have nearly finished my first prototype. so far i have completely finished the box and nearly finished modifying the circuit. i need to glue the circuit, battery snap, led's and the solar panel to my aluminum box. also the solar panel needs to be soldered to the circuit. the red hose around the led is a piece of rubber tube that has been melted over the wire to prevent any shorting of the circuit. the circuit has got the two led's in parallel. i want to have completed my light by Friday when i have the next double period. i have encountered the problem when i had a aaa battery holder instead of an aa battery older. i have resolved this problem by going down to the electronics store and replacing them.

week 5 term 2

this week we are doing our prototype lights. i am posting up photos of mine at its currant stage

my first prototype

this is my first prototype continued. so far, i have folded up my box. i have also made up brackets from scrap metal and have riveted them onto my box to hold it together. also, i have started a back cover to fit onto the back of the box(so the battery is hidden). the box has been bended using a metal bender machine and i have used a metal guilitine to cut out the brackets. a CAM machine was used to cut the box and back plate out. the solar panel will sit ontop of the box and the led's will be on either side of the solar panel