//Project - For every action...//

int Name = Max Seabrooke;

unit title( ) { (DESIGN, Prototyping); project period { 18 April 2011 - 06 June 2011; }}

2

Ball-bearing Volcano RunHaving a vertical tip helps throw the ball bearing upwards whilst still making it to go slightly forwards to allow a smooth transfer to the next jump. If I were to add any more jumps, I may need to put the whole series of jumps at an angle.

Laser Cutting the FrameI used the laser cutter to quickly cut out the multiple parts that would be used to construct the framework for the Volcano shaped ball run. The only problem I found with the laser cutter was that the ply burnt along the edges really badly so sanding and adhering became quite difficult. Next time, it would be best to use specially manufactured laser plywood.

3

Constructing the frameI first tried using PVA to adhere the framework together, however because the edges were badly burnt the PVA would not fix. Instead, I used epoxy resin, which physically worked really well but aesthetically looked messy.

Steam Bending the Birch PlyI used a dishwasher to steam the two sheets of ply. Whilst flexible, I applied Cascamite contact adhesive to the sheets and compressed them together in a jig I made. Cascamite did not hold, I think this was probably because I didn’t mix the right amounts.

I realised that just having one sheet of bent ply would work alright anyway so decided to just steam the ply and put them in jig to dry.I also realised that I should of made a smaller radius for the jig to get a reliable curve.

4

Finishing the constructionI adhered the steam bent ply to the framework I made using epoxy resin. After drying, I then trimmed off any excess wood and sanded.

To attach the two halves of the ramp together and the stands, 5mm threaded metal rod and hex bolts were used. I also decided to use the FDM prototypes I made to attach the vertical stands to each end of the ramps (close up on page 9).

5

Motor and MessageA basic circuit including a button to activate a small motor. A spool attached to the motor reels in the string, pulling and opening a message on paper.

note on coding:The motor only spins when the button is on, a delay could be added to save having to hold the button down.

6

Motor and MessageFor the actual run, I chose to use this stage as the finale. I programmed the motor to only spin after each run had finished using buttons. Instead of having a lot of text, I simply chose to split an image of a pointing hand in three parts so that the sheets of ply could unfold to uncover the image and finally direct to the classic French film ending, ‘fin’.

7

Arrow Shaped Light ArrayAttempting to make a sequence with LEDs that light one after the other to make an arrow form and then repeats. I was able to do this when I had the LEDs connected straight to the Arduino output pins. However this prevents me from adding more output devices.

To spare the output pins, a shift register can be used. I did this but it meant that the coding became more difficult to write.

8

IR Emitter and Sensor TestTo test that I had properly set up the code and circuit for the IR emitter and sensor, I added a button as an input and a motor as an output. The button turned on the IR emitter, therefore triggering the sensor to turn on the motor for a short-period of time.

Shift Register for Light ArrayTo create the arrow shaped light array and not use up too many output pins on the Arduino, I added a shift register. Also at the tip of the arrow, I decided to use a IR emitter LED instead of a red LED so that another process could be triggered to start.

9

Light Array HousingI again used the laser cutter to produce the housing for the light array. However, this time thinner sheets of plywood was used, this meant that the edges were easier to sand down after being burnt by the machine.

Using Solidworks, I created a two-way spacer to be printed on the FDM 3D printer. With the prototype, 5mm threaded rod and rounded hex bolt ends, I was able to space out the LEDs and make the housing free-standing.

I decided to not use the shift register (IC), as it kept faulting on the sequence kept changing after the first loop. Instead I just plugged the LEDs straight into the pins of the Arduino, which also made it easier to code.

10

Ball-bearing Snake RunI used a CNC milling machine to create a smooth pathway for the ball-bearing to run. For a prototype, MDF worked well but doesn’t have a great finish. For the actual process, I will use the CNC mill again but with the hardwood, Beech.

Originally I made the angle of the platform 10º but when I tested it, the ball-bearing just came out the cut grooves. So I changed the angle of the platforms to 5º.

Leg HeightAfter adjusting the cut angle for the platform’s legs a few times, I realised I had got the length wrong for the front legs. So for now I just balanced them out with cutoffs. I need to look into joints as I only used the glue gun to adhere it all together.

11

CNC Milling a block of BeechFor the actual Snake Run stage of the run, I again used the same CAD model created on Solidworks and the CNC mill. However, I decided to use a block of Beech wood instead of MDF as it gives a nicer finish.

I had some problems with the CNC milling machine in the end. The rough cut run worked well but when it came to the surface finishing run, it did not complete cutting every area of the Beech. Even though I had correctly set the machine up. It may have been caused by a slight bow in the actual block of wood.

12

Finishing the Beech Because the CNC mill did not finish all the surfaces, I had to thoroughly sand every everywhere to get a smooth finish.

This then made the ball bearing just roll off the edge so I had to make railing to control the speed and direction.

Making a stand for the Snake RunI had to create a high enough stand so that the ball would have enough speed when it dropped into the ramp below.

The stand distorted the run slightly as it was extremely difficult to get the drill holes to the exact spacing of the metal rod legs.

13

Erupting Bottle - Test V1The first test included the one litre bottle of Diet Cola and five ‘Mentos’. After pulling the release to drop the ‘Mentos’, it didn’t take long for the two ingredients to react. The bowl and drain I created successfully drained the amount I hoped for into a plastic cup.

However, the actual eruption was not what I expected. I hoped for a large stream of the Diet Cola to erupt out so I decided to do another test with different amounts.

14

Erupting Bottle - Test V2This time I used ten ‘Mentos’ for the reaction and a different brand of Diet Cola. This achieved the eruption I hoped for. However, too much of the Cola went into the plastic cup and quickly overflowed.

It would be best to use the same amounts used as test V1.

note:The ingredients in the Diet Cola that cause the eruption are caffeine, potassium benzoate, aspartame, and CO2.

The ingredients in the ‘Mentos’ that react are Gelatin and Arabic Gum.

15

Vacuum Forming On Solidworks, I was able to create the former part that would drain away the Diet Coke after the reaction. Again with the use of the CNC milling machine and MDF, I created a former.

Before putting the MDF former into the Vacuum forming machine, I needed to seal the surface as the MDF fibres were all loose from the cutting. I coated the MDF with sanding sealer, sanding after each coat, until it was completely smooth and sealed.

Before putting the former in machine, I drilled small holes around the edges to make sure the vacuum pulled the polystyrene sheet into every corner. The first form did not turn out well as there was a lot of ribbing around the edges. To prevent this, I added a small piece of wood to along with the former.

After removing the former from the plastic, I used a Gerbil cutter to remove any excess plastic and then finely sanded down the edges.

16

Diet Coke and Mentos stageAfter a test run, I realised that the formed plastic parts I made didn’t work that well as they weren’t angled enough.

I finely raised the angle and they worked well to drain the liquid into the cup below.

17

Levered HammersThis stage of the run was easy to make. As the first hammer dropped after being hit by the slinky falling down the stairs, the next hammer would then also be pulled down with it. The last hammer would then pull pins out of the casing for the Mentos to be released into the Diet Coke bottles.

18

Swinging Weight - Test V1At first, I wanted to create something similar to Newton’s cradle where to process finishes by knocking over a slinky. Instead of ball-bearings hitting each other, I wanted to make molds from clear adhesive tape as I had never used it before.

To give the molds some weight I added caster sugar and then hung them from a frame with wire. However, the final mold didn’t have enough power to trigger the slinky.

Swinging Weight - Test V2I removed all the adhesive tape molds except one to use as a swinging hammer. After a few attempts, I figured out how to set the process up and it successfully knocked over the slinky.

19

Experimenting with JointsFor the legs of swinging weight frame, I wanted to create a angled lap joint. I made a mock up first of this joint and used two dowel pins to fix it tightly into place.

For the top strut of the frame, I experimented with different types of joints.

I first created a angled triangle cut into the wood using a tenon saw and chisel. It would not sit in the angled legs so I created another cut within this. Again it did not work.

The best joint was a triangular cut. I also offset the cut from the end so that the strut sat nicely between the angled legs tightly.

20

I decided to put a pin all the way through the strut to both sides of the legs to help fix it in place as I knew that the whole frame will want to shift when the weight dropped.

21

Triggering the Swinging WeightWith the Aluminium weight on a wire, I attached a toggle to the end so that I could make a trigger to release it easily.

The servo hooked up to the Arduino turns only 90º, pushing the wooden hook down to drop the weight.

I created a very basic stairway for the slinky. Because I used strip pinewood, not all the pieces were straight making it difficult to hammer them together. However, it still worked well enough to carry the slinky.