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...

Saturday, March 16, 2013

The Modern Firepower Pinball Project - Lighting Demo

The lights are fully wired up and tested, and I thought it was time to show them off.

Switches, Lamps and Solenoids are all wired up.  The playfield is almost ready to go into the cabinet.

In the picture above, not only are the lights wired up, but so are the solenoids.  The playfield is almost complete, ready for installation into the cabinet.  I've simply fallen behind on updating the blog.

The only wiring left to complete is the switch and solenoid wiring for the very top eject hole.  I won't be able to install the eject hole assembly and switch until the playfield is removed from the rotisserie, so for the moment wiring is complete.

Click on through to see the pictures and video...

Thursday, February 28, 2013

The Modern FIrepower Pinball Project - Shocking Discoveries

Though overall progress has been slower these past few weeks, wiring is coming along nicely.  48 lamps have been wired up, and I have about 30 more lamps to wire.

Lighting wiring:  Red wire is shared 5v power, green wires are ground control lines that run back to the LED-Wiz.

In the pictures, the red wires are providing shared 5v power to the bulbs, and I used all green wires for the individual grounds that run back to the LED-Wiz.  I have no idea which lamp connects to which port, and I don't need to know since my software will map the lights.

Yes, pinball bulbs are typically powered by 6.3 volts, but I already had a 5 volt 2 amp power source handy, and I found that the brightness was just fine using only 5 volts.  I will cover the power supplies in a later post.

For now, read on to discover the shocking oversight I made in my electrical design...

Tuesday, February 5, 2013

The Modern Firepower Pinball Project - The New Solenoid Power Driver

In the previous update on the Solenoid Power Driver I explained that I had submitted the new PCB design to manufacturing, and also ordered new transistors.

The PCB's came in and they look marvelous!  These prototype PCB's were proudly manufactured in the USA, though I'm not sure where ExpressPCB conducts their full-scale production runs.  This was my first time using ExpressPCB, and I am very pleased with the results.

All the various components fit perfectly onto the ExpressPCB manufactured prototype PCB.

The new design is revision 3.0 of my Pinball Solenoid Power Driver, and is optimal for use with the LED-Wiz as the controller.  Compared to my original design, the new circuit board is not only smaller, it upgrades all outputs to High Power circuitry, and adds fuses for each output as well as the main power source.

My original prototype (brown) had 4 High Power and 12 Low Power circuits, and no fuses.  My new design is much smaller, yet it provides 16 High Power outputs. Every output is fused, along with a separate fuse for the power supply.

The new transistor came in as well, and it... was promptly fried.  Faster than corn in hot oil, these transistors popped as soon as a solenoid load was introduced.  Lowering the voltage to 25V from the normal 50V, these transistors worked just fine, but the solenoids fired weakly.

So now I had a new challenge, to find an even better transistor, but in the same package with the same pinout, and electrically compatible with my freshly milled PCB boards.  The task seemed impossible.

I'm happy to announce that I was successful in my search.  Instead of trying yet another BJT transistor, I went with a Power MOSFET transistor.

Power MOSFETs are different from BJT transistors in that MOSFET's use a small voltage to control a large current, whereas BJT transistors use a small current to control a large current.  Lucky for me, they are available in the same TO-220 package, and the pinout is fully compatible with my existing circuit design.

Testing the new Power MOSFET transistor.  Worked perfectly each and every time.

In preliminary testing the Power MOSFET transistor has performed perfectly.  From a technical standpoint, this transistor even appears to be superior to the MOSFET that Stern Pinball uses, or at least used at one time.  I haven't bothered to research if Stern has chosen different MOSFETs for their more recent games.  Not only is my chosen MOSFET capable of handling more power than Stern's counterpart, it also has quicker response times - roughly twice as fast.

Now the the PCB is assembled, it's time to do some testing.

I've soldered up the first PCB, and it will soon undergo performance and endurance testing in the Modern Firepower pinball machine. 

The new Pinball Solenoid Power Driver v3.0 is small enough to fit snugly on the Modern Firepower playfield.

Wiring for lighting, and now solenoids, continues.  More updates soon...

Saturday, February 2, 2013

The Modern Firepower Pinball Project - Switch Wiring

During the week I completed most of the switch wiring.  It was rewarding to hook the switches up to the PC and monitor the inputs, and every switch tested perfectly!

Switch wiring is 80% complete and tested!

Click on through to check out the details...

Sunday, January 27, 2013

The Modern Firepower Pinball Project - Prep for Wiring

In prep for wiring the playfield, I'm test fitting all of the various circuit boards and components onto the underside of the playfield.  I have to find a place for three LED-Wiz output driver boards, one U-HID switch input board, one Pinball Solenoid Power Driver board (of my own design), and a USB hub to tie them all together.

From the original design concept, I intended to install the circuit boards directly to the playfield.

It is not a requirement that I install any of these components to the playfield.  Alternatively I could have installed the circuit boards in the backbox, like a normal pinball machine.  To install the boards in the backbox would require me to fashion up several wiring harness connectors, as there would be around 150 wires connecting to the playfield.

But since my circuit boards are so small and fit on the playfield, I will only have 3 wires connecting to the playfield:  The 50v power supply, the 5v/12v power supply, and a single USB cable.

Now that's the definition of Modern.