Fooseball goal sensor

[GoingFastTurningLeft]

I am now putting together a fooseball table I got for $62 new (normally $250!!) from K-mart, and it reminded me of a project I wanted to do in college with our old fooseball table. I'm going to be turning it into something like an arcade air hockey game, with automatic score keeping at first, then i'll later add in a timer, sound effects, etc.

My idea was to add into the goal "ducts" a sort of funnel shape right above where the ball return is that will make the ball go down through a certain point, where it will interrupt an infrared beam, at which point it will score the goal. I'm not worried about the specifics of it yet, in theory it seems a pretty ideal solution, especially since it doesn't change the appearance of the table.

Anyone have any other ideas? I'm not looking for any mechanical solutions, and that's not just because I make some nasty shots on goal.

[haklesup]

Well, the optical sensor is hard to match for price and selection since you have transmission (beam) and reflective options to choose from. The reflective type may be easier to implement needing only one viewport and little alignment requirements. Even a small PIR with blinders on could do the job.

Another other sensior I can think of would be a small air pressure sensor. It could be mounted in a hole along the return path and would sense the small puff of air as it rolled over. Could be finikey.

A Microvave proximity detector would also work if adequately shielded in the return path. These are the inexpensive units used with car and house alarms. Nice thing about this is it can see through non metallic things like particle board and plastic. Shielding (the blinders) can be made of Al foil, May have too much range though.

Ultrasonic comes to mind but is overkill for this (unless you want to trigger recorded crowd cheers when the ball gets close). Other than that, you would need a metal or modified ball. (ignoring mechanical switches per your request).

[GoingFastTurningLeft]

Well, after reviewing those options, I think the IR is the best and cheapest solution. Cheap enough to even make it a redunant system. Thanks for your input.

A 'regular' size ball is about 1 1/4" inches in diameter, and is made of a very hard plastic (?) compound, very similar to a billiard ball. Any modification to the ball is out of the question, since it would affect its dynamics.

This said, the 'hole' it would have to pass through could be 1 1/2" in diameter. I've only done one thing with an infrared LED and diode pair, and in that they were butted up against each other, in an "adapter" to allow my college's older VCR automation system to be able to "push" the play button on a new HDD DVD player, and from what I remember testing the diode, it would pick show a strong signal from any remote control a good foot away. I want to say my test circuit was my photo diode hooked up to an LED, and powered by 2 AA batteries.

I really don't think it would be difficult to line up the LEDs and sensors correctly. Just have to epoxy the hell out of them so they don't move.

[SETEC_Astronomy]

I think optical would work but you may also want to try just a plain old switch. You could put a piece of hinged plastic or wood over the goal area (internally) and have it held in place with a light return spring. When the flap is hit by the ball it could actuate a lever switch or anything else along those lines. Just another idea.

[Chris Smith]

And you can purchase a nice surplus counter that takes the micro switch and counts one pulse per score.

They have the resettable and non resettable types and neither needs much in the way of electronics.

Just a power source going though the switch to the counter.

One pulse, one power unit per ball, one count.

[ljbeng]

For the cub scouts pinewood derby track, I used a laser from the junk store, $2 each and I mounted it vertical above the track. In the track I had a visible light sensor with the laser pointed at it. That cost me <$3. I fed the light sensors into a micro and we could determine the winner and flash a light. You could do something similar....

[GoingFastTurningLeft]

^^^ no mechanical switches! There's no room to hang anything behind the goal anyway, and if you put it in the bottom it wouldn't work, because that's where I am going to keep my spare balls. Besides, the whole thing I'm trying to keep as "stock" as possible.

Yeah, the pinewood derby thing does exactly the same thing I'm talking about doing, except with visible light. I'm avoiding visible light because I don't want any glowing coming from the goals when the room is dark

I picked out some 940nm IR emitter (LED) and receiver (phototransistor) for my next parts order, and for both they're about 55 cents. I already have all the other parts I'd need.

I found a webpage on which someone did practically the same thing, except they used it to control a model train set, at junction yards and such. The distance they mentioned using is nice... If behind the goal wasn't slanted so much, i'd be able to use a pair of IR led/trans to measure the speed of the ball... which would be totally asinine

Here's the webpage:
http://home.cogeco.ca/~rpaisley4/ATDetIR.html

If anyone's interested, here's my webpage with the early AVR GCC code i've written. it works no problem in the simulator.

http://www.geocities.com/maxxxpower420/fooseball.html

[Chris Smith]

You can use the pulse from an optical sensor to run they same type of counter. Mechanical Switches, optical, all the same,... they pulse and advance the counter.

[philba]

I bought (at auction, great deal) a foosball table that has exactly what you are talking about. It uses a very simple mechanical switch in the chase where the ball returns to the side tray (not sure what that's called). We don't actually use the electronic scorer very much. It's more satisfying to move one of the counter rings.

I don't think you would want to test for a score at the goal opening as there is a lot of room. You could get some interference and the largish opening could result in missed events. The train thing relies on a fairly narrow opening - a couple of inches max. Your foos goal opening is pretty big. Also, people could stick their hands into the goal and "score" points. I'd follow the ball path to find a place that is shielded from ambient light and more tightly constrained. Maybe place baffles inside the goal to direct the ball to a good spot if it just drops to a tray below the goal. IR would probably be the best choice but a microswitch with a lever could do as well and it's less wiring.

[GoingFastTurningLeft]

Maybe place baffles inside the goal to direct the ball to a good spot if it just drops to a tray below the goal. IR would probably be the best choice but a microswitch with a lever could do as well and it's less wiring.

That's exaclty what it does, and that's exactly what I'm planning to do. "Baffles" Thanks for giving me the proper term. Sounds a lot better than "funnel like thing". There's about 4 or so inches from the top of the playing field to the top of the ball return opening below it. plenty of room to hide everything. It also has a 14" apron, so there's tons of room to hide the controller boards , etc.

I don't plan on putting them at the goal. I have a habit of just throwing around ideas, and not making it clear i'd never do them.

Also, part of this design is the ability to play score based with a "play to 10, up by 2" rule and/or timer based. The play to number (usually 10) is adjustable up to 99 and "up by 2" rule can be turned on or off with a switch.

This is all just an excuse to get more comfortable working with AVR's.