I made some cute decorations for the outside. A panel with the name and a badge to be attached to the walls. 

I spent a lot of the semester working on the electrical components that use solenoids. This was very exciting because it is the main part of the pinball machine. That being said, I am still finding it difficult to generate the appropriate amount of force (130N) to hit the ball. My next step is to work with transformers and relays to help with increased voltage.

I also worked with improving the aesthetics of the pinball machine. There is now a second story (with lights which glow once a certain score is reached) and a habitrail. 

​Next semester I want to integrate all the components and add a belt to return the ball to the start when it goes out.

To make the habitrails I got 5mm rods and bent them. This was very effective, but ensuring the templates were to scale was harder than expected and involved using the grid in the screenshot as a calibration square. This was done in 3D with two 2D templates.

I experimented with making the plunger to shoot the ball at the beginning. This was done by threading a steel and attaching a comfortable rubber stopper.

I also worked on integrating the solenoids into my bumpers, slingshots and flipper. I experimented with various solenoids and even made a higher fidelity version with copper wire.

To activate the bumper the arduino must detect contact between the ball and the bumper. To do this I created an open circuit with an exposed side on the ramp of the bumper and one on the face of the pinball machine. This means when the ball rolls over the ramp it will complete the circuit, activate the bumper and get shot away. I experimented with thin copper sheets, copper tape and AlFoil. AlFoil was the best because it was easily moldable, cheap and did not short circuit with itself like the copper tape did.

The various progressions of my design of solenoids and solenoid activated components is at this link. 

After a couple worries about breakages on the axle of the flipper, I redesigned it to use off-the-shelf components. I used a threaded insert for plastic and a bolt as the axle. This bolt fit very easily and smoothly through my bearing. Another advantage of using the bolt is that I can adjust the flippers' height off the board by screwing the bolt in more or less.  

Additionally, for storage it is much simpler to remove the bolt and take the flipper off to avoid damage.

In future I want to use imperial bolts with a hex head. This means the attachment to the rest of the flipper mechanism can just be the negative to the hex head and the connection between those two parts can be simplified. 

Throughout the semester I spent time taking the code I had previously created and forming an electrical harness for easy debugging on the back. A big problem that occurred was my joints breaking at the protoboard connection. To compensate I added stress relief to the joints.

Additionally, I spent time manufacturing the machine into a higher fidelity prototype. This involved lasercutting the base (mdf with an acrylic cover), adding legs and creating components which effectively fit in the holes. 

The component designs were increased to have more high fidelity models which also accounted for the connections each component would need to have to the board. 

This semester I have created a prototype of a pinball machine with the components 3D printed and working electronics for the main components. 

In the future I would like to manufacture the components out of appropriate heavy duty materials: acrylic and plywood for the base; delrin and rubber for the slingshots and bumpers and flippers; aluminium tubing for the habitrail. I would also like to improve my code with switch statements and shift registers. Finally, to manufacture the individual parts, I need to make the CAD reflect the tools I will use to manufacture each part. For example, I will use a 3 axis CNC for the flippers but my current design has overhangs. Therefore it must be divided into three components with mates. 

I created the initial code for the most important electrical components. 

This code was made as a proof of concept and includes delays, which will not be used once all of the code segments are integrated. 

The aim of the flipper code is to do the aforementioned switch between 50V and 5V with PWM. All the bumpers and slingshots will be controlled with almost identical code. The lights flash in order once the points are greater than a certain value (not included in this code). Every time the ball rolls over a switch, a certain number of points are added to the point tally. Finally the display writes these points on an LCD display. 

In future I will combine all this code into one block that runs through each loop.  

Various circuits

After reflection on my process designing the flippers I have decided that using two voltages in two wires is an inefficient way to solve the problem. I will instead use PWM through an Arduino to vary the voltage through a single wire.

I have created a complete CAD of all the components of the pinball machine. My next steps are to manufacture each component and edit them unit they suit my needs. I will also create the electronics.