Wednesday, April 24, 2013

The Modern Firepower Pinball Project - Playfield Test [VIDEO]

Over the past few years of doing research and development, many times I have had doubts about my ability to build a pinball machine from scratch.

Occasionally a milestone is achieved, like the first time a solenoid is activated from a home-built power supply, or the first time a program you wrote recognized a switch input and energized a solenoid.

Each of these achievements gives you new confidence, but the doubts still linger in the shadows of your mind.  Sure, the individual tests were great, but what happens when you scale up to a full machine?

After a few months of careful assembly and wiring, I was finally able to put all of my doubts to rest.

In mid March I was able to play my first pinball game on my 'Modern Firepower' playfield, and the early results were fantastic.  I put together a multi-angle video to show off my hard work, I hope you like it.

Make the jump for the video...

Friday, April 19, 2013

The Modern Firepower Pinball Project - Power Supplies

WARNING:  THE CIRCUITRY DESCRIBED IN THIS POST USES ELECTRICITY AT LEVELS DEADLY TO HUMANS.  SEEK PROFESSIONAL EXPERTISE IF YOU ARE NOT SURE HOW TO SAFELY USE THE PRESENTED INFORMATION.

One of my very first achievements on my long pinball quest was a home-built solenoid power supply.  Though it was many years ago, I still remember clearly the first time Troy and I activated an old, used and abused solenoid with my home-built power supply.  At that moment I felt like a magician harnessing an invisible, mystical power.

The bottom half of this Williams 'High Power Solenoid Circuit' actually describes most of the power supply design.  J102 is the signal coming from the Transformer, which runs through a Bridge Rectifier (BR3), and a small Capacitor (100uf) and Resistor (10KOhm) provide a small amount of line conditioning.  Not shown here is the circuitry (Switch, Fuse, Line Conditioner and Varistor) that are in the circuit between the AC power source and the Transformer.


But as with most things pinball, for the DIY enthusiast there is a great void of information for what should be a relatively simple topic.  I had spent months researching and building the power supply from scratch, and had no idea if it would really work with pinball solenoids.  It was at that moment, hearing the BAM BAM BAM of the happily activating solenoid, that I first felt capable of overcoming the challenges of building my own pinball machine.

I wish I had all the answers, but to be honest there's still several aspects of pinball power I haven't had the opportunity, or the need, to solve.  But many of the answers I will be providing here I have never seen published anywhere else.  And trust me, I looked.

Power supplies in and of themselves are not complicated beasts.  Any number of books and resources will teach you how to build any of the many types of various power supplies.  If you are interested in building a power supply, I highly recommend you read up before tackling your own project.  In case you're curious, I read 'Building Power Supplies' 2nd Edition by David Lines, which I had picked up years ago at RadioShack for other projects. 

I do not provide enough info here to guide you through the process; rather my goal here is to help you choose the correctly sized power supplies that are needed for a modern, DIY pinball build like my Modern Firepower Pinball Project.

Power supplies are needed for several items in a modern pinball build, primary among those are the solenoids and the bulbs.  In my modernized pinball build, I'm also using a power supply for an industrial USB hub (which in turn powers four connected USB peripherals), and for the ball trough opto-switches.  If you're using any special anima-tronics with motors, you might also need a different voltage power supply just for them.  Every build can have unique requirements, so your choice of components and features will ultimately drive your power supply requirements.

Since I'm using an 32" LCD TV for the backbox (which also powers the speakers), I didn't have to worry about backbox lighting and audio amplifiers.  Obviously the TV came with it's own power supply (built in).  The only other device in the pinball machine is the small PC running Windows, which came with its own power supply.

Since the only real challenging power supply is the solenoid power supply, I'll discuss the other power supplies first, and save the best (worst?) for last.

Read on for more info...