Getting the Parts
Once you have a mostly complete design, you can begin purchasing parts. Purchasing early will be important, especially if parts are being shipped from China. The design also can not be finished until you can take accurate measurements of your actual parts.
Choosing Parts
For a budget build, the cheapest parts available will have to suffice. Sites such as eBay, Aliexpress, and Amazon will provide what you need. Chinese buttons and other components will be acceptable, but for the true arcade quality you will want to purchase identical, high-quality parts.
The Buttons
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For the Sound Voltex controller, you will need a total of 7 buttons. Other controllers will use different sizes, styles, and numbers of buttons. The four large buttons for Sound Voltex are 60mm square buttons. The next two smaller FX buttons are rectangular 50 x 33 mm buttons. The final button, the start button, is a 33 mm square button.
Sanwa manufactures the actual arcade buttons, which can be purchased through a site such as Rakuten. These buttons have the best quality and longest life span along with the true arcade feel. Unfortunately these buttons can also become quite expensive. Instead, the example controller was built using cheaper Chinese clones purchased from aliexpress. For the large buttons, I purchased a set of clones from Aliexpress. From the same site, I purchased a pack of buttons typically used for Beatmania that match the dimensions of the Sound Voltex buttons.
Each of the buttons holds a microswitch, the signaling part of the button. The microswitch will complete an electrical circuit when pressed, allowing the microcontroller to sense a button press or release. The buttons also come with holders for LEDs that can be wired to light up when the button is depressed.
The Encoders
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Encoders are an important part of the Sound Voltex controller but may not be applicable for other controllers. Rotary encoders spin and send signals to indicate how much a shaft has turned. Sound Voltex has dampeners on the encoders to reduce the speed at which knobs can be spun, but this contoller was built without dampeners in order to simplify the process.
When looking at encoders, the accuracy is specified with a number, such as 48 PR. This means that the encoder will recognize 48 points in a full rotation of a shaft. Other controllers built with low accuracy encoders have had issues due to the jumpiness and low precision brought on by the encoders. Here, a 600 PR rotary encoder was used, but that has also had issues with oversensitivity. Given these results, a 360 PR rotary controller is recommended.
The encoder will also need a knob to attach to the shaft. Aluminum volume knobs tend to give a nice feel and typically are manufactured to size that would fit most shafts on rotary encoders. I purchased a set of knobs from eBay, though there are many other replacements for it.
Each encoder has a different pinout or wiring pattern. Be extra careful when checking diagrams and your parts. Wiring an encoder incorrectly may damage or entirely destroy the encoder.
The Microcontroller Board
Each controller will need a control board to read the inputs from the buttons. The inputs will be processed and sent to the computer where the game is running. In this case, an Arduino Leonardo was preferred due to its ability to function as a Human Input Device (HID) such as a keyboard and mouse. More information on microcontroller choice is available in the Programming section.
Extras
Depending on how much you want to accomplish with your controllers, there may be additional parts you may need. I chose a strip of addressable LEDs in order to allow for additional lighting and animations. Some controllers may need special components such as knobs, speakers, joysticks, etc. These should be easy enough to find through the same avenues as the other arcade controller parts although additional research may be necessary.
Bill of Materials
Depending on where you shop and what parts you may already have on hand, a custom controller can be very budget friendly. Provided is a the bill of materials used for this controller. Not all parts may be exactly what you need. They can be interchanged depending on the needs of each controller, but should be able to serve as a baseline for beginning to look at parts.
Next Steps
Once you have received your parts, it’s time to finalize the design and get manufacturing! Inspect your parts and ensure that they function before beginning anything else. Broken parts will make later steps more difficult should issues arise. In addition, getting familiar with how each part will mount to the plates will be useful. Take accurate measurements of the dimensions for each mounting point and you’ll be ready to finish your design.