Skee Ball Home Build.....Electronics Help Wanted

[loggergolf]

I have been thinking about/wanting to try building my own skee ball machine. Web searches about that idea are what led me to this forum, and I've learned a great deal already by reading the threads of a couple others doing the same project (and very impressively).

I feel comfortable with the building of the 'machine'....as in, the structure itself. Where I am lacking is in the electronics department. I'm not necessarily looking to do anything more than the standard skee ball scoring system, basic display, etc. I have very limited knowledge of programming (a couple courses in school) and am not too familiar with the products I should be looking for/using/etc.

I would love it if someone would take the time to kind of write out the basic idea for how wiring something like that would go. What software/hardware I should look at, how it gets put together, things like that. It would have to be pretty beginner in tone, at least at first. I don't expect this project to happen fast, and I'm more than willing to educate myself on things before diving in, just need a roadmap as to what I'll be working on.

Thanks in advance for your time...

Matt

[MonMotha]

For your scoreboard: http://www.sparkfun.com/commerce/product_info.php?products_id=8530

or something similar, of course.

I'd grab a microcontroller development board to handle all this on as there's no reason to attempt to one-off something custom for this.  Microcontrollers are designed to run small programs that interact directly with "raw" inputs.  Things like PCs aren't particularly good at that, but they'll work.  Something like an Arduino would be a pretty good fit, and it comes with a set of libraries that attempt to make things easier to program for people not used to embedded programming, and there's a large community surrounding them.  They're also fairly cheap.

[BobA]

The earlier machines used switches in the path of the ball.  Each switch incremented a counter by 10 so the top spot got 5 clicks and the 10 spot got 1 click. A counter is very easy to breadboard with a couple logic chips and drive 7 segment displays.  1 think there was another switch that stopped play when all the balls were returned. The switches were originally mechanical but you could easily use IR trans and receivers so there would be no mech adjustment required.

Just my thoughts KISS.

[MonMotha]

I'd argue that all of the counter tricks and multiple clock pulses required to do it the "old" way are far more complicated than just writing a little C or C++.  There are lots of examples out there for the Arduino, and the libraries included are specifically designed to make it easy for beginners.

They built them that way in the past because it was all they had: microcontrollers as we know them today didn't really exist then, and full blown microprocessors required lots of external parts and weren't cheap.  Nowadays, you just grab a microcontroller, wire the inputs up, wire the outputs up, and chuck a little software at it.  Lot more flexible if you want a weird game type ("Now get a 20 or 40 for a special bonus!"), too.

I would recommend the use of IR sensors.  They won't wear out and should not require as much mechanical effort to get working.

[loggergolf]

Thanks for the great info so far guys....I've been reading up on the Arduino and that seems like a good solution and within my abilities with a little more studying.

As far as IR sensors go....Where to look? Anything particular to look for as far as compatibility to the Arduino  system?

So big picture here I'm looking at the microcontroller receiving inputs from the IR sensors for each 'target' (hole) and sending outputs to the seven segment number display. How easy/hard would it be to wire a 'start' button toward the front of the machine? I am trying to decide on the ball release system....I've been thinking just a manual release as it seems like a mechanical one might draw too much power for this kind of system. Thoughts?

Thanks again for the great advice...

Matt

[MonMotha]

One of the nice things about microcontrollers is that you can pretty much wire buttons directly to them.  The AVRs upon which the Arduino is based have integrated pull-up resistors, so you can literally just wire a button between an IO pin and ground, turn on the pull-up resistor, and read the input with a 0 being "button pushed" and a 1 being "button not pushed".  I'm guessing the Arduino libraries further automate this for you (I generally just program the "bare metal" AVRs with none of the Arduino libs, so I'm not sure of them).  So yeah, a start button is no problem.

For transmissive/interruptive IR solutions, you've got a few options.  You can buy discrete IR LEDs and phototransistors.  These aren't too hard to work with.  Basically, the phototransistor will act like a closed switch when it sees IR light in abundance and will "go open" when the IR light is blocked.  The light source would then be an IR LED that you wire up just like a normal LED except you can't tell when it's on because you can't see it   You can also get somewhat more "integrated" solutions that add some analog signal conditioning to the detector side to give a true "logic level" output.  Might make your life a little easier, but those tend to be like 20 bucks a piece for some strange reason.  Sparkfun has a number of IR options on their IR sensors page.  You can also start poking around at good ol' Digi-Key, Mouser Electronics, Allied Electronics and other places.

There also exist reflective IR sensors.  They're mostly used when you want to sense something without having access to put a receiver on the other side (but maybe you can put a reflector on the object you want to sense or a passive reflector on the other side).  Probably not necessary in this case, and those are more complicated to design for.

For hooking up to your Arduino, you just want a digital on/off or "logic level" output from the sensor.  A bare phototransistor with a weak pull-up resistor on the collector like the internal one to the AVR or about a 10k external one and grounded emitter will probably give you something pretty close to this at low cost.

[loggergolf]

Ok....Getting closer to understanding all this

Another (probably stupid) question....How am I attaching the IR sensors to the Arduino? It looks like they have legs that can plug in, but how is it handled when they are located in different spots around the machine?

I've been reading alot and getting a much better understanding, but still a ways to go. Thanks very much for your help...

Matt

[MonMotha]

You'll just run wires from the sensors to the appropriate locations on the Arduino board.  You'll probably end up making some sort of custom little circuit on perfboard, a breadboard, etc., or you may just solder components like resistors inline.

Somebody probably makes a "shield board" to make this easier for you.