Here’s what one of the button looks like with the quick connect wires attached to its data terminals:Logic BoardThis component is the brains of the system — it’ll need to be able to receive input from the arcade buttons, send output signals via the LEDs in the buttons and run some custom logic to keep track of task completion.There are many single board computer or microprocessor board options here, I decided to go with the Arduino Uno because:I already had one sitting around doing nothing and it was about time I used it.It’s easy to program and has a free integrated development environment.It uses 5v so has enough to power the LEDs in the arcade buttons.Arduino boards make a lot of sense for embedded projects as there’s no operating system or other complexity — you flash your code onto the board and it just runs it with no appreciable boot up time when the power is turned on.Crucially, it has 14 digital data pins… this project needs all of these as we have 7 buttons to read the status of and 7 LEDs to toggle..Each of these will need a unique digital pin.Arduino Uno R3 (Photo credit: arduino.cc)With all fourteen digital pins taken up with the buttons representing the seven days of the week, how does the red (reset) button fit into the picture?.Thankfully the Arduino has a separate hardware reset pin that we can wire the button to and this doesn’t use up one of the fourteen digital logic pins..I’ll cover how that works during assembly.I also didn’t fancy doing lots of soldering to connect fourteen data wires, plus ground and the reset wiring to the Arduino..To avoid that, I added a screw shield, which sits over the Arduino headers and allows you to connect wires by clamping them with screws rather than solder..These are also great for prototyping things as you can rewire things easily.Power SupplyI wanted a single power supply system that would be capable of powering the Arduino and illuminating all seven of the green LED buttons simultaneously..This turned out to be an easily met requirement as Adafruit sells a 12v / 1A power adapter with the right sort of barrel jack for the Arduino..To make things neat and tidy..All in all, the power supply system parts look like this (before some cutting and soldering during assembly):AssemblyAssembling the hardware was a pretty satisfying phase of the project although it did involve soldering a lot of ground wires together!.I measured where I wanted to place the buttons, then used Forstner drill bits to cut precise circles in the PVC junction box — these are designed for this specific job and do it really well!The drilling process did make quite a mess which, although easy to sweep up, could get in your eyes so be sure to use eye protection if trying this!.I used a 25mm drill bit and also made a smaller hole in the side of the box for mounting the power jack.Attaching the arcade buttons is then very simple as they just screw into place with the fitting that Adafruit ships them with:When fitting the arcade buttons I made sure that the terminal with the red paint mark on it was in the top right position for each one, meaning that the wiring setup for each would be as follows:Each of the ground terminals on the buttons needed wiring together so that they were all linked to one to two wires that could be attached to the Arduino’s ground pins (it doesn’t have enough of them otherwise)..This involved a lot of messy (as I’m not very good at it) soldering.. More details