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Mini Pinball 07: Designing the PCB -- Episode 314

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element14's The Ben Heck Show

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The prototype for the mini pinball machine has a 16x2 LCD display, audio amplifier, 16 switches in, 16 lights out, 4 MOSFET controllers, and 4 servo ports. In today’s episode, Ben translates this prototype into an Eagle design. Felix works on finding the libraries and the part numbers while Ben Does the layout. 

 

 

Ben puts together the PCB for the mini pinball machine in Eagle. He starts with some of the more cumbersome areas first, namely the lights and switches. He’s going to use these molex 2.54 or .1 inch pitch headers.  He puts in the 16 switch molex connectors in and 16 for the lights. He’s got to think about how to orient the circuits in relation to the 16 switch molex connectors.  He creates spacing so that they are able to make an adapter board that can attach for testing.  He won’t run the traces until he has the main components on the board. There should be enough space between these.

He lays out placement for the power, the microcontroller, the screen, and input/output plugs on the lower-left. He shows the schematic of the constant current LED driver.   Ben reuses a layout of an eagle file for the schematic of the constant current LED driver. They used the TLC59282 constant-current sink driver in the persistence of vision episode and Super Space Shuttle.  You source the LED with current and then it sinks into the device. After laying out a lot of the parts for the board to run the digital signals Ben needs to attach the SPI signals between the Teensy/Arduino and the I/O chips. At this point he’s added 2 MOSFET packages, headers for the solenoids, voltage regulator, placement for the Teensy and Arduino, and some resistors.

After running the traces the PCB is done.  Power comes in through the 2.1 millimeter jack and goes to a push button switch.  A large capacitor for the 12 volt line goes to a 5 volt regulator which also has an electrolytic capacitor on it.  This regulator goes to the 5 volt input of the Arduino or the 5 volt input of the Teensy. Both the Teensy and the Arduino output their own built-in regulators.  That 3 volt regulator goes to the switch integrated circuits. There are 16 switches and 16 lights.  The light driver has 16 bits of switch input. There are connectors for 4 servos, a large electrolytic capacitor next to those servos because servos can draw a lot of power and cause spikes in power. The audio amplifier is set to a fixed gain and finally the speakers where they hook up.  Then there is the LCD screen with a silkscreen along the screw holes. The silkscreen is .26 inches in diameter. This represents the head of the screw to make sure that it’s not bumping into anything. After doing a design check, the design is ready to be sent off to get boards made.

Ben uses a schematic of an LCD display that fits his requirements but lacks an Eagle file so he’ll have to do his own.  When working with schematic design software it is often necessary to either hunt down a library or make one. For rare parts it can be quicker to make one.  For the schematic, the symbol is representative of the part, whereas the package detail comes from the datasheet. Ben creates a package that matches the physicality of the hardware.

 

Disclaimer

  • in reply to makerkaren

    Yes, we have complete control of how to implement the idea.

     

    Brainstorm with Ben about the dynamic allocation idea to see what he thinks.  All we have to do is come up with a good play and learn sequence.  The rest is just implementation.

     

     

     

    DAB

  • in reply to DAB

    Hitting mechs in a certain sequence can be pretty challenging, even for a seasoned player. What if they acted more like recipes? To achieve this goal, you have to hit these particular mechs that light up for that round. Once they are all hit, you move onto the next step with a different set of mechs lit up. Think that would get the message across just as well?

  • in reply to makerkaren

    Hi Karen,

     

    This one of those fun with science themes that I think could appeal to the STEM crowd.

     

    Even a low resolution screen can be used to identify which bumpers have the sequence and the point value.  Yes it will make the game different, but then you want a marketing discriminator.

     

    All the screen needs to do is pop up a view of the game board identifying where each bumper is and where it sits in the sequence.  Think of using LED's and color coding to help guide the player along.  If they hit the wrong sequence, then you select one of the bumpers at random to establish a level reset so they can continue to play the game with the current ball in play.

     

    So when you start at level zero, you identify the sequence of starting the great expansion.  (We probably need to go off line to go into the detail, but once your team has identified the number and positions of the bumpers, we can go through a reasonable sequence of events.

     

    When you achieve level one, the screen puts up the next bumper sequence for the player.

     

    You continue this approach through all of the levels to become Master of the Universe.

     

    Along the way, the player learns the basics of how the universe works and the proper sequence for the theory. (yes you should go get a copy of my book)

     

     

     

    At that point, you have a dynamic game (new idea), a challenge for players, and a learning tool all in one.

     

    DAB

  • in reply to DAB

    That sounds really cool, but also sounds rather deep. Do you think it would appeal to mass audiences? While I like the idea, I'm not sure how to visual convey all the concepts you have as steps. Do you have ideas on how that could be made clear visually in a pinball game? Keep in mind that our digital display is probably going to be pretty low res.

  • in reply to jpickens

    Collect fuel, build rocket, avoid aliens... That sounds familar..

    image

  • in reply to makerkaren

    You could do a couple of unique approaches, like set up a set of bumpers that must be hit in a precise sequence to get the score and advance up a level.

     

    You could also do popups when a sequence is meet to establish a "money" shot to demonstrate your knowledge and your skill.

     

    My basic sequence is in the following steps.

     

    1. initiate the great expansion (aka the Big Bang)

     

    2. initiate stellar fusion to begin making complex mass objects.

     

    3. create the first atoms starting with the first proton and building the atomic elements.  (You could have one target to indicate the number of protons and another for electron equivalents)

     

    4.Star burnout resulting in the first large dense mass objects (aka black holes)

     

    5. End of the expansion and the beginning of contraction.

     

    6. The big Crunch and rebirth.

     

     

     

    DAB

  • in reply to makerkaren

    Its a Pinball machine, so succesfully landing could be one goal, another could be making fuel from local sources, doesn't have to be too detailed, just "Power up, Landed Safely", or "Fuel Production Increased" or "Fuel supply running out!!"

  • in reply to insanewayne

    Sadly, it would be too difficult and expensive to use any licensed themes. Do you have any other ideas that wouldn't require a license?

  • in reply to DAB

    That sounds pretty intense. How do you see that translating into interactive mechs and gameplay?

  • in reply to jpickens

    So what would the "Mission" be? What would be your goals? Are you trying to land on the planet? Or you already on the planet? Are aliens/creatures involved?