Saturday, November 15, 2008

Evaluation of final product

My final design has taken a long time and a lot of hard work to get it looking like it is today. I have encountered many problems but I over came them by modifying my design and using my initiative. I am happy with the final product and I'm proud to say that I made it.

My original conceptual design was completely different to the one I made. The original was very complicated and not quiet to my taste so I changed it to something that I preffered. When I found out the dimensions could be enlarged I changed the size from 120mmx120mm to 200mmx200mm. I also never planned to have a arcylic plastic strip through the middle (between my top and bottom plate). I only decided to have it towards the end of the year.

In the first half of the year we went on a class field trip to the tomb of the unknown soldier, Waitangi park and civic square. These three destination have built in solar powered lights everywhere. We examined these lights for shape, how they worked and how they effected the environment. We also drew sketches of these lights and noted what materials they were made of. After the field trip we researched materials for ourselves. I researched aluminium and arcylic plastic as I planned to use mainly aluminium and possibly arcylic. Lucky I did because in the end I did use arcylic. We also did research on the poacita grass that our light were aimed to light up. This was helpful because it confirmed that my light was a good shape for the job.

On free hand (a computer programme) I played around with my new design even further. I then finished what I wanted my design to look like and made my mock up out of card board. Hard card board and i used masking tape and hot glue to seal it. My mock up looks similar but not identical to my final product.

My first problem with my design was that when I put it in the cam2 machine, I hadn't set it down hard enough so I wasted a piece of aluminium. Terry was not happy. The next time I strapped it down harder with double sided tape and masking tape. This made a great result and gave me a perfect top plate. The one problem with it was that I couldn't use the metal sheet bender to bend it into place. So instead i improvised and used my hands. This worked surprisingly well but I would have received a better result with the metal sheet bender.

Then I came across another problem. Because of my bizarre shaped top plate I would have to create my brackets for it through trial and error. It took me three periods to figure out how to make them properly. This was inconvenient time wasting and left me further behind the class.

This was the point were Terry suggested making the arcylic mould for in between the top and bottom plate and I chose to do it. I came in on a Saturday and made the shape out of my mould out of wood. This went smoothly but it took me three attempts to get the actual arcylic mould. mainly because the heat was too high and I wasn't great at using the vacuum machine.

So alas my light fits all the specification and constraints but one. My light exceeds the budget of $30.

But anyway, I continued with my light and asked Terry to help me with the vacuum machine and he got it to work and my arcylic mould came out perfectly. I then used the cam2 machine to cut out my bottom plate. I nearly made the same mistake as last time but I corrected myself just in time. When I got the bottom plate (after the cam2 had cut it) I bent it into shape again using my hands. I didn't need brackets for the bottom plate because I had designed my arcylic mould to fit into the bottom plate and it could be used as brackets. So I riveted them together and began on my circuit.

This circuit was no friend of mine. First off, I took out the wires and battery snap and re-wired it. I then spent hours trying to get the LED's working. I say LED's because I had modified the circuit from a series circuit with one 3.6v LED to a parallel circuit with two 3.2v LED's. Yet later on this deemed pointless as it seemed the circuit was fried anyway. So Terry got me a new circuit which I had to redo the process of re-wiring it and so on. I then spent a hour switching round the wires of my LED's and re-soldering the wires onto the circuit until I finally got the circuit working. Divine intervention.

Then I drilled holes in my top plate and a piece of arcylic plastic for my soler panel wires to go through. The arcylic plastic piece was so the was a gap between my solar panel and top plate. This made sure the circuit didn't corrode. I stuck the arcylic piece on with some incedibly strong glue. I then stuck the solar panel onto the arcylic bit and sealed the edges with silicon. Then I put the bottom plate and arcylic mould onto the top plate with the circuit inside. I took a picture of this inside a dark corner using a schools camera and I was finished.

I am very happy with the final product and I'm glad that I completed it. I am proud to say that I made it.

Henry Nicholls

PEACE

Friday, November 14, 2008

Evaluation (document and changes to final design)

My Design has changed considerably. At first I had a very complicated design but then I changed my mind about it and drew up conceptual ideas of a new preferred design. The size also changed when I found out I could enlarge it. I changed it from 120x120mm to 200x200mm.

The enlargement of the final product did not interfere with size of the rivet holes or the size of my brackets. Though the complete change in design I needed to shape my brackets differently to fit the bizzar top plate shape and I had to bend them less than 90 degrees and I needed to move the rivets holes from where orinally planned so the rivets on opposing sides didn't clash.

I decided to use aluminium in the end over stainless steel because aluminium is cheeper and completely suitable for the constraints and specifications. Besides, Terry had already ordrered a lot for everyone in the class.

When I had finished my top plate, Terry suggested that I make an arcylic mould to fit in between my top and bottom plates of aluminium. I already had a similar idea to his forming in my head so I thought I pursued Terrys idea and made the arcylic mould. This did slightly hinder my design prcess as I had already made the brackets for the bottom plate but I had made the arcylic mould able to fit into the bottom plate of my light and used as brackets. so I threw away the original brackets.

I re-wired the curcuit i was given and modified it. I changed it from a series circuit with one 3.6v LED to a parallel circuit with two 3.2v LED's. I also changed my solar panel from the originally planned massive one, to the small stock panel becuase I was running out of time and I wouldn't be able to order it.

These were the changes I made to my final product.

Evaluation (Brief, specs and constraints)

In My brief it stated that my light had to be smaller the 200x300 mm, automatically turn on at night and off throughout the day and it had to be robust enough to endure wind rain and salt water as it would be used by my client (Dr Tony House) in the Coromandel. Also the light must not exceed the budget of $30.

My light sits on the ground, so it can be hidden under the poacita grass and light it up at night. It fits the size constraint as it's dimensions are 200x200 mm and 75 mm deep.

I built in a LDR into the circuit (light dependant resistor) which can sense sunlight so the battery charges up through the day with the solar panel and then during the night the light turns on and releases the energy stored in the battery.

My light consists of mainly aluminium and a little bit of arcylic plastic. The aluminium is the top and bottom plates and the rivets. I used arcylic plastic through the middle for the light of my LED's to shine out from. Neither materials aluminium or arcylic plastic are corrosive. My light also sits quiet flat to the ground an is sealed so wind and sand will not be a problem and seeing as it will not corrode, this light will be perfect for my client, Dr Tony House.

I regret to admit that I exceeded the $30 budget. I used 2 or 3 dollars worth of rivets and a 3 dollar circuit and a mere 2 dollars for a small peice of plastic which I put in between my top plate and solar panell to prevent corrosion. But I used 3 squares of aluminium in the CAM2 machine. One of these was a accident. I also made two mistakes when using the vacum form material which cost probl a exrta 40 dollars, as Im told. So I did not achieve the budget specification.

But in the end, the majority of the specifications and constraints were kept to and I tried my best to fulfill them and I am now happy with the result

Monday, November 10, 2008

Tools list


materials order form


circuit clean up


bottom plate attatched to arcylic mould


Week 5 T4 DTM

last friday we had no school and on saturday I was busy so I couldn't come in. This has left me a fair bit behind schedual and I only have 1 more lunch time to finish my light. On monday I skipped science to come into the workshop to work and I attatched my bottom plate to the arcylic mould with rivets. I then came back after school and did some work on the circuit for my light but to no avail. Today I am blogging so I think I will end up coming back after school on wednesday. besides my evaluations and pictures, this is my last blog

Tuesday, November 4, 2008

bottom plate with bending guide lines


bottom plate being filed


Bottom plate after cam machine


Week 4 T4 DTM

Last Friday I spent my time cutting out my bottom plate in the cam machine and scavenging around our classes prototype lights for old circuits. On tuesday I cut away some bits of my bottom plate with the band saw so I could bend it into shape and get the best result. Today I am blogging and putting on pictures of the past week. we have friday off so on saturday I will come in and I hope to finish the exterior of my light.