Monthly Archives: September 2013

Status as of 9/18/2013

Last week was spent moving pinball machines from VT to MA, and doing some ordering for Disaster.  I bought a bunch of cheap 48V power supplies off ebay.  They are low current but should be good for testing the solenoid driver card at 48V instead of the 5V/12V that I used for the initial testing.

I bought a PC power supply that is beefy enough to be used for a boost converter from 12V to 48V.  I’m pretty certain that I’m going to power most of the low voltage solenoids/lighting/motors with a PC power supply.  They are inexpensive and ubiquitous.  The one question that I have is should use the PC power supply and a boost converter to switch the 12V supply up to 48V.

My current guess is that I need approximately 15A at 48V to power the high power solenoids.  The 15A is complete conjecture on my part, and I won’t really know what the real requirements are until I take some current measurements using an oscilloscope.  (Tried to win a free oscilloscope at work today and failed.  Guess I have to continue to scour ebay looking for a good deal.)

There are currently two different designs for the 48V source.  The first design using the 12V supply from the PC power supply and then a boost converter to up the voltage to 48V.  One difficulty in the design is that an inductor with a very high saturation current is needed.  (about 100A).  The second design would use a simple full bridge and smoothing capacitor to convert the AC into DC, and then a P channel FET driven by a microcontroller to act as a voltage voltage regulator.   Best case would be finding an inexpensive 48V power supply, but I haven’t located that yet.

I bought a couple pieces of acrylic to act as a playfield surface.  I bought a small piece to make the mini-pinball machine which will prove out the driver, input and lighting cards.  The second piece of acrylic is for the Disaster playfield.  I have to go through my extra parts box and see how many things I’m missing to make the mini-pinball playfield.

Last thing is the new Taxi machine.  To say it doesn’t work is an understatement.  At this point it doesn’t boot.  I need it to be up and running by Thanksgiving.  I just ordered a bunch of basic soldering supplies, supplies for surface mount, and a bunch of general things.  Most of this stuff Mark had in his basement, and we just used his supply.  (While Pb may be a big no, no in new electronics, it still reigns supreme in the Taxi machine.)  I bought a good amount of lead solder for re-wetting connectors, etc.

Since so many things are not working on it (i.e. not booting), I need to visually inspect the whole machine and see what is the problem.  Just a quick look last night was Q73 and Q75 were toasted.  One of the pop bumpers is seized.  One of the kickers switches was always closed.  Guess it’s time to start with testing all the voltages.


Status September 2013

June, July and August have been rough months.  No substantive updates.  The new job is taking up a lot of my spare time.  I have been able to play a large number of pinball machines, and continue to believe that the overall concept of Disaster is solid.  Time…that is what I am missing.  As things get more settled with the move, I will be able to put more time back into it.

I was over on pinside today, and there was a topic about the cost of creating a pinball machine from scratch.  They listed it at half a million.  (Saying it requires a game designer, mech eng, electrical eng, firmware eng, graphics artist, and a sound guy)  Since Disaster also involves doing video in the backbox, it needs somebody who can also do animation/video editing.

So let’s take these jobs one at a time.   Game designer…well the initial take is done but will need a lot of refining.  The plan is to do a white wood layout and make incremental changes to fix the flow and shots.  Mech eng…Mark was going to work on the mechanicals, and will probably still help me, but since we don’t live near each other, this will be difficult.  The plan is to minimize the BOM by keeping the number of coil types to an absolute minimum.  That gets the volume of those coils up and reduces the inventory of coils needed.  To get that to happen, it will require more mechanical engineering.  Electical eng…well that’s me.  Firmware eng…well that’s me again.  Graphics artist…hmmm, I’m working on that, and the best that I can hope for is some static graphics for the sides of the machine and the playfield.  Even that much work is up in the air because I’m basically begging for it.  Sound guy…didn’t even think about that.  Animation and video editing…again, nobody slated for it.  My current plan is to create a white wood, bring it to a couple locations, and then start begging for help.

So this means the focus should be on doing whatever is necessary to get the white wood working and playing.  A couple of 48V power supplies were ordered today.  These can be used to verify the driver cards that I’ve populated.  Those have been tested at low current/low voltage, but I didn’t have a power supply to kick the voltage up to real levels.  If anybody has an old power pinball power supply (about 48VDC) that they would be willing to part with, I’m definitely interested.  I may end up stealing the power supply out of one of my other pinball machines to do some testing.  In the short term, the little 48V power supplies I just bought should work fine.  I’m looking forward to kicking some solenoids in the next few weeks.

Way too much time has been spent on trying to get streaming video working.  Right now the machine can stream videos, but I don’t have any videos for it to stream.  I could spend another hundred hours getting that stuff working really well, but the videos still wouldn’t exist.  Short term goal is to just display the score on a monitor.  This shows the functionality of communication from the real time controller to the video controller.

Other small things that have happened.  Received a USB vendor ID/product ID from Openmoko.  So to create an official product that uses the USB, you need a vendor ID/product ID.   Some chip manufacturers let you use their vendor ID, and will assign you a product ID.  The chip that I chose doesn’t offer that, so normally a company would pay 5K or 10K.  That’s not in the budget, so what to do?  If the project is an open hardware project, send an email to openmoko, and they will magically send you a product ID using the vendor ID they purchased from  So the Open Pinball Project vendor ID = 0x1d50, product ID = 0x6070.  Thanks again to the Openmoko project for supporting open source projects.

This weekend all my machines move from VT to MA.  Then a night at Pinball Wizard arcade up in Pelham.  I call it research.